docs: provide reproducible multi-platform publisher

Dockerfile

@@ -7,12 +7,17 @@ RUN pip wheel --no-cache-dir --wheel-dir /wheels .
 FROM builder AS test
 RUN pip install --no-cache-dir /wheels/*.whl
 COPY tests ./tests
+COPY scripts ./scripts
 CMD ["python", "-m", "unittest", "discover", "-s", "tests", "-v"]
 
 FROM python:3.11-slim
 ENV PYTHONDONTWRITEBYTECODE=1 PYTHONUNBUFFERED=1
-RUN groupadd --gid 1001 archive-control \
+RUN if ! getent group 1001 >/dev/null; then \
-    && useradd --uid 1001 --gid 1001 --no-create-home archive-control
+        groupadd --gid 1001 archive-control; \
+    fi \
+    && if ! getent passwd 1001 >/dev/null; then \
+        useradd --uid 1001 --gid 1001 --no-create-home archive-control; \
+    fi
 COPY --from=builder /wheels /wheels
 RUN pip install --no-cache-dir /wheels/*.whl && rm -rf /wheels
 USER 1001:1001

README.md

@@ -77,6 +77,13 @@ four eager-mesh routes, transfer/eviction/unarchive workflows, and the
 adversarial matrix without live infrastructure or Telegram. See
 `e2e/README.md`.
 
+## Deployment Preflight Tests
+
+Check deployment configuration immediately before bringing a new node online.
+The reusable read-only preflight validates the deployed image's filesystem and
+API view against its Docker bind mounts. See details in
+[docs/deployment-preflight.md](docs/deployment-preflight.md).
+
 The complete cross-project design, protocol, workflow, safety, deployment,
 Telegram UX, and testing documentation is published under [`docs/`](docs/).
 

deploy/production/README.md

@@ -1,30 +1,74 @@
 # Production deployment
 
 These files are the non-secret, host-specific deployment manifests for the
-initial x1/x2/lithium topology.
+initial x1/x2/lithium topology and the later helium archive node.
 
 - Install the x1 and x2 files as
   `~/compose/ArchiveControl-cache/{compose.yaml,client.toml}`.
 - Install the lithium files as
   `~/compose/ArchiveControl-archive/{compose.yaml,client.toml}`.
+- The helium directory contains three isolated compose-project manifests. Install
+  them under `~/Repositories/compose/{qbittorrent-helium,syncthing-helium,ArchiveControl-archive}`
+  as described in `helium/README.md`.
 - Create sibling `state`, `backups`, and `secrets` directories owned by the
   configured container UID/GID.
 - Secret files are never committed. Each `secrets` directory contains
   `archive_control_token`, `qb_password`, and `syncthing_api_key`, each a
   regular non-empty file with mode `0600`.
 
-The Syncthing mounts intentionally reproduce each instance's `/var/syncthing`
+## Hardlink-safe bind-mount topology
-layout, including nested data binds. This lets route discovery and route
-provisioning use one safe API-to-local path mapping without altering an
-existing Syncthing configuration.
 
-Before starting a stack, validate it with:
+For an archive source, the qB content path and every Syncthing route used for
+staging must resolve through the **same container mount**. Matching host
+filesystem device IDs alone is insufficient: two separate Docker bind mounts
+have different mount IDs and `link(2)` may return `EXDEV` across them. The
+client deliberately treats that case as copy-only and performs a full payload
+free-space check.
+
+Automatic routes always use the Syncthing API path `routes/<route-id>`. Bind
+that path from a dedicated directory beneath the qB data root, then map the
+same path through the qB client mount:
+
+```yaml
+# Syncthing compose project
+volumes:
+  - /srv/syncthing-config:/var/syncthing
+  - /srv/downloads/.archive-control-routes:/var/syncthing/routes
+
+# Archive Control client compose project
+volumes:
+  - /srv/downloads:/data/qb
+  - /srv/syncthing-config:/data/sync
+```
+
+```toml
+[syncthing]
+api_root = "/var/syncthing"
+local_root = "/data/sync"
+local_path_overrides = { "/var/syncthing/routes" = "/data/qb/.archive-control-routes" }
+```
+
+Do **not** mount the route directory separately into the client. The override
+is the authoritative mapping and keeps qB source files and automatic route
+folders in one mount namespace. Existing manually configured Syncthing folders
+below the qB tree may retain their own exact overrides. Use API-visible paths,
+not Syncthing folder IDs, as override keys.
+
+Before starting a stack, validate its config and then run the generic host
+preflight with that machine's own paths and container names:
 
 ```sh
 docker compose config
 docker compose run --rm archive-client --check-config
+python3 scripts/preflight-deployment.py --help
 ```
 
 The check is fail-fast and performs local permission, filesystem, sparse-file,
 hard-link, and reflink probes. Normal startup additionally probes the local
 qBittorrent and Syncthing APIs before registration.
+
+`scripts/preflight-deployment.py` is deliberately topology-agnostic: pass the
+host's `client.toml` and its client, qBittorrent, and Syncthing container names.
+It resolves Docker mounts rather than assuming project names or host paths. It
+also catches a common fatal error: a Syncthing `api_root` that names its config
+volume rather than the mounted shared-data tree.

deploy/production/helium/README.md

@@ -0,0 +1,34 @@
+# Helium archive-node deployment
+
+This directory contains the non-secret manifests for the dedicated helium
+archive node. Install the files into these separate compose projects:
+
+- `~/Repositories/compose/qbittorrent-helium/compose.yaml`
+- `~/Repositories/compose/syncthing-helium/compose.yaml`
+- `~/Repositories/compose/ArchiveControl-archive/{compose.yaml,client.toml}`
+
+The qBittorrent API and Syncthing GUI/API bind only to loopback. Syncthing
+transport/discovery ports are published normally. qBittorrent data and
+Syncthing route folders both live under `/media/Data2`; the Archive Control
+container therefore mounts `/media/Data2` once at `/data/storage` so archive
+placements can hardlink rather than make a full copy.
+
+`/media/Data2/Downloading` already contains unrelated files. The fresh qB
+instance must not import or manage them; only Archive Control-created torrents
+are managed.
+
+Before the first client start, run the repository preflight on the target host
+(replace container names if that host uses different compose project names):
+
+```sh
+python3 scripts/preflight-deployment.py \
+  --client-config ~/Repositories/compose/ArchiveControl-archive/client.toml \
+  --client-container archive-control-helium-archive-client-1 \
+  --syncthing-container helium-syncthing-syncthing-1 \
+  --qbittorrent-container helium-qbittorrent-qbittorrent-1
+```
+
+It is read-only: it checks the configured API roots resolve to the same host
+paths as the client roots, that both data roots share one client bind mount for
+hardlinks, secret-file permissions, filesystem capabilities, and the local qB
+and Syncthing APIs. It does not send the control token or modify any container.

deploy/production/helium/archive-control-compose.yaml

@@ -0,0 +1,19 @@
+name: archive-control-helium
+
+services:
+  archive-client:
+    image: sodium/archive-clients:v0.1.19
+    user: "1000:1000"
+    restart: unless-stopped
+    network_mode: host
+    command: ["--config", "/etc/archive-control/client.toml"]
+    environment:
+      QB_USER: admin
+    volumes:
+      - ./client.toml:/etc/archive-control/client.toml:ro
+      - ./secrets:/run/secrets:ro
+      - ./state:/var/lib/archive-control
+      - ./backups:/var/backups/archive-control
+      # Do not split this into separate qB and Sync bind mounts: hardlinks
+      # require both trees to resolve within this one mount namespace.
+      - /media/Data2:/data/storage

deploy/production/helium/client.toml

@@ -0,0 +1,42 @@
+client_id = "helium-archive"
+display_name = "helium archive"
+role = "archive"
+control_endpoint = "ws://bot.everdream.xyz:8766/archive_control"
+shared_token_file = "/run/secrets/archive_control_token"
+state_db = "/var/lib/archive-control/client.db"
+backup_dir = "/var/backups/archive-control"
+
+[connection]
+registration_timeout = "10s"
+heartbeat_interval = "15s"
+offline_timeout = "45s"
+reconnect_initial = "1s"
+reconnect_max = "60s"
+reconnect_reset_after = "60s"
+reconnect_jitter = true
+
+[jobs]
+stall_after = "30m"
+verification_timeout = "30m"
+poll_interval = "1s"
+free_space_reserve_bytes = 33554432
+
+[backup]
+interval = "6h"
+recent = 12
+daily = 14
+weekly = 8
+
+[qbittorrent]
+endpoint = "http://127.0.0.1:8081"
+username = "${QB_USER}"
+password_file = "/run/secrets/qb_password"
+api_root = "/downloads/Downloading"
+local_root = "/data/storage/Downloading"
+
+[syncthing]
+endpoint = "http://127.0.0.1:8384"
+api_key_file = "/run/secrets/syncthing_api_key"
+api_root = "/var/syncthing/Sync"
+local_root = "/data/storage/Sync"
+advertised_addresses = ["dynamic"]

deploy/production/helium/qbittorrent-compose.yaml

@@ -0,0 +1,24 @@
+name: helium-qbittorrent
+
+services:
+  qbittorrent:
+    image: sodium/qbittorrent-nox:5.2.3-lt2-1-proxy-listen-amd64
+    environment:
+      PUID: "1000"
+      PGID: "1000"
+      TZ: Etc/UTC
+      WEBUI_PORT: "8081"
+      TORRENTING_PORT: "6881"
+    command: ["--webui-port=8081", "--confirm-legal-notice"]
+    volumes:
+      - ./config:/config
+      # This is deliberately one parent mount. Archive Control maps both the
+      # qB and Syncthing subtrees through the same mount namespace.
+      - /media/Data2:/downloads
+    ports:
+      # Keep the published and internal WebUI ports identical: qBittorrent
+      # rejects a forwarded request whose Host header carries a different port.
+      - "127.0.0.1:8081:8081"
+      - "6881:6881/tcp"
+      - "6881:6881/udp"
+    restart: unless-stopped

deploy/production/helium/start-syncthing.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+set -eu
+
+home=/var/syncthing
+api_key=$(cat /run/secrets/syncthing_api_key)
+
+if [ ! -f "$home/config.xml" ]; then
+    syncthing generate --home="$home" --no-port-probing
+fi
+
+exec syncthing serve \
+    --home="$home" \
+    --gui-address=http://0.0.0.0:8384 \
+    --gui-apikey="$api_key" \
+    --no-browser \
+    --no-port-probing \
+    --no-restart \
+    --no-upgrade

deploy/production/helium/syncthing-compose.yaml

@@ -0,0 +1,19 @@
+name: helium-syncthing
+
+services:
+  syncthing:
+    image: syncthing/syncthing:2.1.2@sha256:4464f4161dd0251e20d46bb3aec83363db75d80cef1abdd5d5fd4054b04a004d
+    user: "1000:1000"
+    hostname: helium
+    entrypoint: ["/bootstrap/start-syncthing.sh"]
+    volumes:
+      - ./start-syncthing.sh:/bootstrap/start-syncthing.sh:ro
+      - ./secrets:/run/secrets:ro
+      - ./config:/var/syncthing
+      - /media/Data2/Sync:/var/syncthing/Sync
+    ports:
+      - "127.0.0.1:8384:8384"
+      - "22000:22000/tcp"
+      - "22000:22000/udp"
+      - "21027:21027/udp"
+    restart: unless-stopped

deploy/production/lithium/client.toml

@@ -19,7 +19,7 @@ reconnect_jitter = true
 stall_after = "30m" # Status warning only; it does not fail the job.
 verification_timeout = "30m"
 poll_interval = "1s"
-free_space_reserve_bytes = 1073741824 # Rechecked immediately before work.
+free_space_reserve_bytes = 33554432 # 32 MiB; payload bytes are added for copy paths.
 
 [backup]
 interval = "6h"
@@ -39,4 +39,5 @@ endpoint = "http://syncthing:8384"
 api_key_file = "/run/secrets/syncthing_api_key"
 api_root = "/var/syncthing"
 local_root = "/data/sync"
+local_path_overrides = { "/var/syncthing/routes" = "/data/qb/.archive-control-routes" }
 advertised_addresses = ["dynamic"]

deploy/production/lithium/compose.yaml

@@ -2,7 +2,7 @@ name: archive-control-archive
 
 services:
   archive-client:
-    image: sodium/archive-clients:v0.1.2
+    image: sodium/archive-clients:v0.1.14
     user: "1000:1000"
     restart: unless-stopped
     command: ["--config", "/etc/archive-control/client.toml"]

deploy/production/x1/client.toml

@@ -19,7 +19,7 @@ reconnect_jitter = true
 stall_after = "30m" # Status warning only; it does not fail the job.
 verification_timeout = "30m"
 poll_interval = "1s"
-free_space_reserve_bytes = 1073741824 # Rechecked immediately before work.
+free_space_reserve_bytes = 33554432 # 32 MiB; payload bytes are added for copy paths.
 
 [backup]
 interval = "6h"
@@ -39,4 +39,7 @@ endpoint = "http://127.0.0.1:8384"
 api_key_file = "/run/secrets/syncthing_api_key"
 api_root = "/var/syncthing"
 local_root = "/data/sync"
+# This existing folder is physically inside the qB data tree. Map it through
+# that same client bind mount so source staging can use hardlinks.
+local_path_overrides = { "/var/syncthing/DownloadsSync" = "/data/qb/Sync", "/var/syncthing/routes" = "/data/qb/.archive-control-routes" }
 advertised_addresses = ["dynamic"]

deploy/production/x1/compose.yaml

@@ -2,7 +2,7 @@ name: archive-control-cache
 
 services:
   archive-client:
-    image: sodium/archive-clients:v0.1.2
+    image: sodium/archive-clients:v0.1.14
     user: "1001:1001"
     restart: unless-stopped
     network_mode: host
@@ -16,4 +16,3 @@ services:
       - ./backups:/var/backups/archive-control
       - /home/ubuntu/Downloads:/data/qb
       - /home/ubuntu/compose/syncthing/st_home:/data/sync
-      - /home/ubuntu/Downloads/Sync:/data/sync/DownloadsSync

deploy/production/x2/client.toml

@@ -19,7 +19,7 @@ reconnect_jitter = true
 stall_after = "30m" # Status warning only; it does not fail the job.
 verification_timeout = "30m"
 poll_interval = "1s"
-free_space_reserve_bytes = 1073741824 # Rechecked immediately before work.
+free_space_reserve_bytes = 33554432 # 32 MiB; payload bytes are added for copy paths.
 
 [backup]
 interval = "6h"
@@ -39,4 +39,8 @@ endpoint = "http://127.0.0.1:8384"
 api_key_file = "/run/secrets/syncthing_api_key"
 api_root = "/var/syncthing"
 local_root = "/data/sync"
+# `DownloadsSync-X2` is ~/Downloads/Sync on the host, nested below the qB
+# root. Resolve it through /data/qb rather than a second nested bind mount so
+# source staging can hardlink it.
+local_path_overrides = { "/var/syncthing/Downloads/Sync" = "/data/qb/Sync", "/var/syncthing/routes" = "/data/qb/.archive-control-routes" }
 advertised_addresses = ["dynamic"]

deploy/production/x2/compose.yaml

@@ -2,7 +2,7 @@ name: archive-control-cache
 
 services:
   archive-client:
-    image: sodium/archive-clients:v0.1.2
+    image: sodium/archive-clients:v0.1.14
     user: "1001:1001"
     restart: unless-stopped
     network_mode: host
@@ -16,4 +16,3 @@ services:
       - ./backups:/var/backups/archive-control
       - /home/ubuntu/Downloads:/data/qb
       - /home/ubuntu/compose/syncthing/st_home:/data/sync
-      - /home/ubuntu/Downloads/Sync:/data/sync/Downloads/Sync

docs/README.md

@@ -16,8 +16,9 @@ credentials and host-specific details.
 6. [Storage safety and recovery](storage-safety.md)
 7. [qBittorrent and Syncthing integration](service-apis.md)
 8. [Configuration, deployment, and usage](deployment-and-usage.md)
-9. [Telegram UX](telegram-ux.md)
+9. [Deployment preflight tests](deployment-preflight.md)
-10. [Testing strategy](testing.md)
+10. [Telegram UX](telegram-ux.md)
+11. [Testing strategy](testing.md)
 
 The independent protobuf source of truth lives in the
 `cabbage/archive-control-proto` repository. Generated bindings in this

docs/decisions.md

@@ -35,8 +35,11 @@ expand these rules but must not contradict them.
   manifests, and observed external state.
 - SQLite backups use the online backup API. Defaults are every six hours, 12
   recent, 14 daily, and eight weekly copies, plus pre/post-migration backups.
-- Default concurrency is one active data-moving job per client and per route.
+- Default concurrency is unrestricted: every eligible queued job is admitted
-  Disjoint node pairs may run concurrently. Queueing is durable FIFO.
+  in one scheduler pass and independent jobs execute concurrently on a client.
+  Physical qBittorrent, Syncthing, disk, and network capacity are therefore
+  the natural limit. `enforce_concurrency_limits=true` restores the optional
+  legacy per-client/per-route gates. Commands for one job remain serialized.
 - A queued job owns a per-resource reservation. Cancelling it removes only the
   queued record/reservation and never sends cleanup commands.
 - Connectivity or transfer stalls wait indefinitely. A configurable 30-minute

docs/deployment-and-usage.md

@@ -44,6 +44,9 @@ command_max_attempts = 3 # Total sends, including the initial attempt.
 stall_after = "30m" # Warning state only; jobs continue waiting.
 route_policy = "on_demand" # Alternative: eager_mesh.
 route_setup_timeout = "30m"
+# Default: allow all eligible jobs; disk/network/service capacity is the limit.
+enforce_concurrency_limits = false
+# Used only when enforce_concurrency_limits is true.
 max_active_per_client = 1
 max_active_per_route = 1
 max_envelope_bytes = 1048576
@@ -92,6 +95,7 @@ backup_dir = "/var/backups/archive-control"
 registration_timeout = "10s" # First response must arrive within this window.
 heartbeat_interval = "15s" # Server may negotiate a different effective value.
 offline_timeout = "45s"
+outbound_enqueue_timeout = "15s" # Reconnect rather than wedging if sends stop draining.
 reconnect_initial = "1s"
 reconnect_max = "60s" # Retry forever, never wait longer than this.
 reconnect_reset_after = "60s"
@@ -102,7 +106,7 @@ stall_after = "30m" # Warning only; no automatic job failure.
 verification_timeout = "30m" # Stopped qB full-recheck deadline.
 poll_interval = "1s" # Active qB/Syncthing observation interval.
 # Worst-case copy fallback must leave this many bytes free.
-free_space_reserve_bytes = 1073741824
+free_space_reserve_bytes = 33554432 # 32 MiB; payload bytes are added for copy paths.
 
 [backup]
 interval = "6h"
@@ -125,6 +129,16 @@ local_root = "/data/sync"
 advertised_addresses = ["dynamic"]
 ```
 
+When an existing Syncthing folder is physically nested in the qB data root,
+use a `local_path_overrides` entry to map that exact Syncthing API path through
+the same client bind mount. This enables hardlinks without creating two Docker
+mount boundaries for the same host files. Do not add a second bind mount for
+the nested folder: Linux treats it as a distinct mount even when it has the
+same `st_dev`, and the client correctly falls back to copy-only capacity
+accounting. The override key is the normalized Syncthing folder path beneath
+`api_root`, not its folder ID. See the production deployment README for the
+required compose and override pattern.
+
 The remaining node examples omit optional `[connection]`, `[jobs]`, and
 `[backup]` tables and therefore use these same defaults; deployments may
 override them per node.
@@ -213,7 +227,7 @@ cache/archive routes according to policy.
 ```yaml
 services:
   archive-client:
-    image: sodium/archive-clients:v0.1.2
+    image: sodium/archive-clients:v0.1.14
     user: "1001:1001"
     restart: unless-stopped
     command: ["archive-client", "--config", "/etc/archive-control/client.toml"]
@@ -246,6 +260,28 @@ Generated protobuf Python bindings are committed in each consumer with the
 exact `archive-control-proto` tag/commit recorded. Release order is proto,
 control consumer, client consumer, E2E, then image publication.
 
+### Reproducible multi-platform Buildx lifecycle
+
+The named Buildx builders are local acceleration/cache only; they are not a
+deployment dependency and can be removed after publication. Use the checked-in
+publisher: it installs only the non-native binfmt handler, creates a temporary
+rootless BuildKit builder, verifies both platforms, publishes the index,
+displays its digest, then removes both temporary resources.
+
+```bash
+scripts/publish-image.sh vX.Y.Z
+scripts/publish-image.sh vX.Y.Z --also-latest
+```
+
+The publisher deliberately uses `moby/buildkit:rootless` with
+`--oci-worker-no-process-sandbox`. On nested Docker hosts, the default OCI
+sandbox can fail while masking `/proc/acpi` for an emulated build; rootless
+BuildKit confines that compatibility setting to the disposable builder. It
+refuses to publish unless `docker buildx inspect` reports both `linux/amd64`
+and `linux/arm64`, and removes the builder and binfmt handler on success,
+failure, or interruption. Retain the displayed manifest digest in release
+notes and deploy the immutable tag or digest.
+
 ## Operator usage
 
 1. Prepare local qB, sync, state, backup, config, and secret mounts with the

docs/deployment-preflight.md

@@ -0,0 +1,121 @@
+# Deployment preflight tests
+
+Run the deployment preflight on every new node after its qBittorrent and
+Syncthing stacks are running, but before starting the Archive Control daemon
+for normal operation or creating any routes/jobs. It does not contact the
+control daemon, alter Syncthing/qBittorrent state, or print secret contents.
+It does create and remove two unique, zero-byte probe files while proving that
+the live client mount topology permits hard-link staging; no resource data or
+configuration is modified.
+
+The script is [`scripts/preflight-deployment.py`](../scripts/preflight-deployment.py).
+It deliberately takes paths and container names as arguments rather than
+assuming hostnames, compose project names, mount paths, credentials, or roles.
+It can therefore be used unchanged on cache and archive nodes.
+
+## Requirements
+
+- Run it on the Docker host being checked.
+- Use Python 3.8 or newer. The script reads the mounted configuration through
+  the client image, so it does not depend on the host Python TOML library.
+- Have Docker CLI access to the daemon.
+- Have the checkout containing the script available on that host, or copy only
+  this script into the node's compose directory.
+- Bring up qBittorrent and Syncthing first. Do not start the normal Archive
+  Control daemon yet.
+
+The disposable client container below uses the exact `archive-client` service
+image, mounts, environment, and network specified by that node's compose file.
+Consequently its qB/Syncthing API probes validate the same runtime environment
+the daemon will use, not the host shell's network namespace.
+
+## New-node procedure
+
+The example uses generic names. Replace paths, compose project directories,
+service names, and real container names for the node being deployed.
+
+```sh
+# 1. Bring up only the local dependencies.
+cd /srv/compose/syncthing-node && docker compose up -d
+cd /srv/compose/qbittorrent-node && docker compose up -d
+
+# 2. Create a temporary client from the exact production image/config, without
+#    running the daemon or registering it with control.
+cd /srv/compose/ArchiveControl-archive
+docker compose run -d --no-deps --name archive-control-preflight \
+  --entrypoint sleep archive-client infinity
+
+# 3. Discover the real dependency container names if needed.
+docker ps --format '{{.Names}}'
+
+# 4. Run the deployment checks. They include a disposable hard-link probe.
+python3 /path/to/archive-clients/scripts/preflight-deployment.py \
+  --client-config /srv/compose/ArchiveControl-archive/client.toml \
+  --client-container archive-control-preflight \
+  --syncthing-container syncthing-node-syncthing-1 \
+  --qbittorrent-container qbittorrent-node-qbittorrent-1
+
+# 5. Remove the temporary container, then start the real daemon only after a
+#    successful result.
+docker rm -f archive-control-preflight
+docker compose up -d archive-client
+```
+
+If the real client configuration is mounted somewhere other than the standard
+`/etc/archive-control/client.toml`, pass that in-container location explicitly:
+
+```sh
+python3 scripts/preflight-deployment.py ... \
+  --container-config /custom/path/client.toml
+```
+
+## Required arguments
+
+| Argument | Meaning |
+| --- | --- |
+| `--client-config` | Host path to the exact `client.toml` that will be mounted into the daemon. |
+| `--client-container` | Running disposable or already-running client container to inspect and probe. |
+| `--syncthing-container` | Running Syncthing container for this node. |
+| `--qbittorrent-container` | Running qBittorrent container for this node. |
+| `--container-config` | Optional `client.toml` path inside the client container; defaults to `/etc/archive-control/client.toml`. |
+
+## What it checks
+
+- The future automatic `routes/<route-id>` path resolves through Docker mounts
+  to the same host path as its client-side mapping.
+- That future route path and qBittorrent content root use one client bind
+  mount, so hard-link staging remains possible rather than silently falling
+  back to a space-consuming copy.
+- A real `link(2)` operation between a unique zero-byte file in the qB root
+  and one in the future automatic-route root. The probe verifies that both
+  names refer to the same inode and removes them unconditionally.
+- Every existing `archive-control:*` Syncthing folder beneath `routes/` still
+  has its local directory. This catches a route-root bind-mount migration that
+  would otherwise hide an already configured folder and later fail a job with
+  `No such file or directory`.
+- The token, qB password, and Syncthing API-key files are non-empty regular
+  files with no group/world permissions.
+- The client image can read its configuration and reports usable permissions,
+  sparse-file support, and filesystem capabilities for both roots.
+- qBittorrent authentication/version compatibility and Syncthing
+  authentication/device identity are healthy from the client container.
+
+In particular, if `syncthing.api_root` is the Syncthing configuration root,
+bind its `routes` subdirectory from a dedicated directory beneath qB's data
+root and add a `local_path_overrides` mapping for that exact API path. This
+prevents automatic route folders being created on a small configuration
+filesystem while the client expects to hardlink from the qB data mount.
+
+When converting an existing node, stop its client and Syncthing containers,
+move each existing `routes/<route-id>` directory from the old Syncthing config
+tree into the new qB-backed route-root directory, then recreate Syncthing and
+run this preflight. Do not discard existing route directories: they can contain
+route handshake state or an in-progress transfer namespace.
+
+## Failure handling
+
+Treat a nonzero exit status as a deployment blocker. Correct the compose
+mounts, `client.toml`, secret permissions, service credentials, or service
+image/version that the message identifies, then rerun the same command. Do not
+work around a mapping failure by creating route folders manually: the route
+provisioner relies on those API/local path mappings being exact.

docs/protocol.md

@@ -45,8 +45,8 @@ seconds. A connection stable for 60 seconds resets the backoff.
 
 ## Version and feature negotiation
 
-The envelope and registration both state the sender version. Major `1` accepts
+The envelope and registration both state the sender version. Major `2` accepts
-only major `1`; a different major is rejected. The negotiated minor is the
+only major `2`; a different major is rejected. The negotiated minor is the
 highest mutually supported minor no greater than either endpoint's advertised
 minor.
 
@@ -96,19 +96,22 @@ client state snapshot before a route can become ready.
 
 Every mutating command includes an expected job revision or immutable job
 definition plus the expected last global event sequence. A stale revision or
-sequence is rejected without side effects. The control daemon sends only one
+sequence is rejected without side effects. Assignment is represented solely by
-active step command for a job and waits for its persisted completion event
+the durable assignment `CommandAck`; it produces no `JobEvent`. The control
-before commanding the next participant. This single-writer lease lets whichever
+daemon sends only one active step command for a job and waits for its persisted
-client owns the current step allocate the next global per-job event sequence;
+completion event before commanding the next participant.
-the following command starts from the sequence control has durably accepted.
 
 ## Events, progress, and reconciliation
 
 Each client-originated job event has a unique ID, monotonically increasing
-global per-job `sequence`, and resulting job revision. Duplicate IDs/sequences
+global per-job `sequence`, resulting job revision, and the `command_id` of its
-are idempotent only when their complete content matches. Control never grants
+owning `ExecuteStepCommand` or `CancelJobCommand`. Duplicate IDs/sequences are
-concurrent event-writer leases for one job. A gap or conflicting duplicate
+idempotent only when their complete content matches. Control verifies the
-pauses destructive orchestration and requests snapshots.
+client, acknowledged command lease, expected cursor, and active step before
+accepting it. A gap, conflict, or stale lease triggers a durable authoritative
+`ReconcileJobCommand`: the client retires only the named stale command leases
+and restores that job cursor, without deleting resource data or unrelated job
+state.
 
 `fraction_complete` is current-step progress and
 `overall_fraction_complete` is the weighted five- or three-step job progress;
@@ -120,7 +123,7 @@ On registration, active-job cursors provide the client's revision, last event
 sequence, state, and commit flag. Reconciliation applies these rules:
 
 1. Equal cursors resume normal delivery.
-2. A client behind receives safe replay/snapshot commands.
+2. A client behind receives an authoritative reconciliation command.
 3. Control behind requests and validates the client's full job snapshot.
 4. Conflicting commit evidence reserves the resource and requires manual
    reconciliation; neither side performs cleanup.

docs/service-apis.md

@@ -29,6 +29,10 @@ The adapter accounts for terminology/behavior changes such as paused versus
 stopped states. It does not mutate qBittorrent preferences, categories, tags,
 limits, queueing defaults, or global save-path behavior.
 
+Syncthing route validation normalizes both absolute and `~/` folder-path
+spellings under the configured sync root before comparing an existing folder;
+an equivalent pre-existing pair is adopted without rewriting it.
+
 ### Inventory normalization
 
 For each torrent the client derives canonical v1/v2 identity from reliable API
@@ -85,9 +89,11 @@ left unchanged.
 
 Syncthing may serialize a folder path relative to its home as `~/...`. The
 client normalizes that notation beneath the configured API-visible sync root
-before applying the API-to-local root mapping. Deployments must mirror
+before applying the API-to-local root mapping. When that folder is nested
-Syncthing's nested bind mounts into the client so the normalized API path and
+below qB's content root, an exact `local_path_overrides` entry must map it
-the client filesystem path refer to the same bytes.
+through the qB bind mount. Do not mirror it as a second nested client bind
+mount: it denotes the same host bytes but a distinct mount namespace boundary,
+which prevents hardlink staging.
 
 Provisioning uses idempotent device and folder configuration updates. Each
 client receives its peer device ID and optional advertised addresses

docs/system-design.md

@@ -133,10 +133,13 @@ a resource may be active or queued at a time. This prevents incompatible
 baselines even when jobs would use different nodes or observe different sides
 of a hybrid identity.
 
-Defaults allow one active data-moving job per client and one per route. A job
+By default every eligible queued job is claimed in the same scheduler pass and
-must acquire its source client, target client, route, and resource reservation
+independent jobs run concurrently on each client; physical service and storage
-atomically. Disjoint node pairs may run concurrently. Route setup is a
+capacity are the limit. Set `enforce_concurrency_limits=true` on control to
-preflight activity and does not permit a data step to bypass these leases.
+enable the optional one-per-client/one-per-route gates. A job always retains
+its resource reservation, and commands for the same job remain serialized.
+Route setup is a preflight activity and does not permit a data step to bypass
+the resource reservation.
 
 Offline nodes do not prevent unrelated jobs from being listed or run. A job
 requiring an offline node remains waiting indefinitely; it does not consume an
@@ -154,6 +157,12 @@ advances to the next step. On reconnect:
 4. Control observes relevant qBittorrent, Syncthing, staging, and manifest
    state before selecting retry, resume, compensation, cleanup, or manual
    intervention.
+
+If a connection disappears while a synchronous job operation is in progress,
+the client journals events locally, reconnects indefinitely, and serializes a
+replayed command behind the in-flight operation for that job. The replay reads
+the journal rather than repeating the data operation. This applies to every
+transfer step, including post-commit staging cleanup.
 5. A command is reissued with its original ID when the acceptance result is
    uncertain.
 

docs/telegram-ux.md

@@ -25,8 +25,10 @@ What do you want to do?
 [ Evict Cache ] [ Job Status ]
 ```
 
-All subsequent pages edit this message. `Cancel` closes the active selection
+All subsequent pages edit this message. Leaving a resource/tree selection
-flow. `Back` returns one level while retaining validated filters/selections.
+returns to the Archive Control operation menu without closing the shared
+conversation. Confirmation `Cancel` returns to its immediate prior selection;
+the main menu alone can close Archive Control.
 Callback payloads contain opaque session/action IDs, not resource names or
 paths, and are validated against persisted session revision and expiry.
 

docs/testing.md

@@ -225,7 +225,7 @@ Fixtures include small deterministic v1, v2, and hybrid torrents with:
 | Recovery | restart every step on source/target/control, lost DB with proof, ambiguous loss fails closed |
 | Messaging | duplicate command/event, lost ack, sequence gap, stale revision, duplicate client ID |
 | Safety | attempted download, corrupt same-size file, symlink/path escape, special file, partfile mismatch |
-| Operations | stall retains percent, offline wait, cancellation each phase, postcommit cleanup retry |
+| Operations | stall retains percent, offline wait, cancellation each phase, postcommit cleanup retry, disconnect/reconnect during every transfer step with exactly-once replay |
 | Database | online backup under load, pre/post migration, retention, corrupt backup rejection, offline restore |
 | UI | pagination/filter chain, stale/double callback, persisted session, clear vs evict separation |
 

docs/workflows.md

@@ -102,6 +102,10 @@ and placement policy differ.
   external state rather than being downloaded or silently deselected.
 - Confirm free space/reserve, permissions, sparse capability, supported
   partfile format, route health, and negotiated protocol features.
+- Charge payload bytes against free space only when the specific source and
+  destination files cannot be hardlinked. Same-filesystem hardlink stages and
+  merges retain the configured reserve plus small metadata artifacts, rather
+  than reserving a duplicate logical payload.
 - Export the source `.torrent` metainfo.
 - Persist the exact source, target baseline, requested selection, and delta.
 

examples/client.toml

@@ -21,7 +21,7 @@ verification_timeout = "30m"
 # Poll qBittorrent and Syncthing at this interval while a step is active.
 poll_interval = "1s"
 # Space that must remain free after a worst-case copy fallback.
-free_space_reserve_bytes = 1073741824
+free_space_reserve_bytes = 33554432
 
 [backup]
 interval = "6h"

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "archive-clients"
-version = "0.1.2"
+version = "0.1.21"
 requires-python = ">=3.11"
 dependencies = ["protobuf==7.35.1", "websockets==16.0"]
 

scripts/preflight-deployment.py

@@ -0,0 +1,327 @@
+#!/usr/bin/env python3
+"""Validate a host's Archive Control Docker deployment before it is used.
+
+This intentionally relies only on the config file and the named containers on
+the host where it runs. It never reads secret contents or calls a remote
+control daemon. The hard-link probe creates uniquely named, empty files in
+the configured qB and automatic-route directories and removes them afterward.
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import os
+import stat
+import subprocess
+import sys
+from dataclasses import dataclass
+from pathlib import Path, PurePosixPath
+from typing import Any
+
+
+class CheckFailure(RuntimeError):
+    pass
+
+
+@dataclass(frozen=True)
+class Mapping:
+    source: Path
+    destination: PurePosixPath
+
+
+def docker_inspect(container: str) -> dict[str, Any]:
+    result = subprocess.run(
+        ["docker", "inspect", container], check=False, text=True,
+        capture_output=True,
+    )
+    if result.returncode:
+        raise CheckFailure(f"cannot inspect container {container!r}")
+    try:
+        value = json.loads(result.stdout)
+        return value[0]
+    except (json.JSONDecodeError, IndexError, TypeError) as exc:
+        raise CheckFailure(f"invalid Docker inspection for {container!r}") from exc
+
+
+def map_path(container: dict[str, Any], path: str) -> Mapping:
+    candidate = PurePosixPath(path)
+    matches: list[tuple[int, Mapping]] = []
+    for mount in container.get("Mounts", []):
+        if mount.get("Type") not in {"bind", "volume"}:
+            continue
+        source, destination = mount.get("Source"), mount.get("Destination")
+        if not isinstance(source, str) or not isinstance(destination, str):
+            continue
+        destination_path = PurePosixPath(destination)
+        try:
+            relative = candidate.relative_to(destination_path)
+        except ValueError:
+            continue
+        matches.append((len(destination_path.parts), Mapping(
+            Path(source).joinpath(*relative.parts), destination_path
+        )))
+    if not matches:
+        raise CheckFailure(f"{path} is not backed by a Docker bind/volume mount")
+    return max(matches, key=lambda item: item[0])[1]
+
+
+def container_user(container: dict[str, Any]) -> str | None:
+    value = container.get("Config", {}).get("User")
+    return value if isinstance(value, str) and value else None
+
+
+def require_same_path(label: str, left: Mapping, right: Mapping) -> None:
+    if left.source.resolve(strict=False) != right.source.resolve(strict=False):
+        raise CheckFailure(
+            f"{label} host paths differ: {left.source} != {right.source}"
+        )
+
+
+def require_regular_secret(path: Path) -> None:
+    try:
+        mode = path.stat().st_mode
+    except OSError as exc:
+        raise CheckFailure(f"secret is unavailable: {path}") from exc
+    if not stat.S_ISREG(mode) or stat.S_IMODE(mode) & 0o077 or path.stat().st_size == 0:
+        raise CheckFailure(f"secret must be a non-empty mode-0600 regular file: {path}")
+
+
+def route_local_path(syncthing: dict[str, Any]) -> str:
+    """Resolve the fixed, future automatic ``routes/`` path in the client."""
+
+    api_root = PurePosixPath(syncthing["api_root"])
+    candidate = api_root / "routes"
+    overrides = syncthing.get("local_path_overrides", {})
+    if not isinstance(overrides, dict):
+        raise CheckFailure("syncthing.local_path_overrides must be a table")
+    matches: list[tuple[int, PurePosixPath, str]] = []
+    for raw_api, raw_local in overrides.items():
+        if not isinstance(raw_api, str) or not isinstance(raw_local, str):
+            raise CheckFailure("syncthing.local_path_overrides entries are invalid")
+        root = PurePosixPath(raw_api)
+        try:
+            relative = candidate.relative_to(root)
+        except ValueError:
+            continue
+        matches.append((len(root.parts), relative, raw_local))
+    if matches:
+        _, relative, local_root = max(matches, key=lambda item: item[0])
+        return str(Path(local_root).joinpath(*relative.parts))
+    try:
+        relative = candidate.relative_to(api_root)
+    except ValueError as exc:
+        raise CheckFailure("future route path is outside syncthing.api_root") from exc
+    return str(Path(syncthing["local_root"]).joinpath(*relative.parts))
+
+
+def run_client_check(container: str, config: str, flag: str) -> None:
+    result = subprocess.run(
+        ["docker", "exec", container, "archive-client", "--config", config, flag],
+        check=False, text=True, capture_output=True,
+    )
+    if result.returncode:
+        detail = result.stderr.strip() or result.stdout.strip() or "failed"
+        raise CheckFailure(f"client {flag} failed: {detail}")
+    print(result.stdout.strip())
+
+
+def mounted_config(container: str, config: str) -> dict[str, Any]:
+    """Read normalized non-secret config through the client image itself."""
+
+    program = '''import json,sys
+from pathlib import Path
+from archive_clients.config import ClientConfig
+config=ClientConfig.load(Path(sys.argv[1]))
+value={"shared_token_file":str(config.shared_token_file)}
+value["qbittorrent"]={"api_root":str(config.qbittorrent.api_root),"local_root":str(config.qbittorrent.local_root),"password_file":str(config.qbittorrent.password_file)}
+value["syncthing"]={"api_root":str(config.syncthing.api_root),"local_root":str(config.syncthing.local_root),"api_key_file":str(config.syncthing.api_key_file),"local_path_overrides":{str(api):str(local) for api,local in config.syncthing.local_path_overrides}}
+print(json.dumps(value,sort_keys=True))'''
+    result = subprocess.run(
+        ["docker", "exec", container, "python", "-c", program, config],
+        check=False, text=True, capture_output=True,
+    )
+    if result.returncode:
+        detail = result.stderr.strip() or result.stdout.strip() or "failed"
+        raise CheckFailure(f"cannot load mounted client config: {detail}")
+    try:
+        value = json.loads(result.stdout)
+    except json.JSONDecodeError as exc:
+        raise CheckFailure("mounted client config output is invalid") from exc
+    if not isinstance(value, dict):
+        raise CheckFailure("mounted client config is invalid")
+    return value
+
+
+def run_service_check(container: str, config: str) -> None:
+    program = '''import json,sys
+from pathlib import Path
+from archive_clients.config import ClientConfig
+from archive_clients.probes import probe_root
+from archive_clients.services import probe_qbittorrent,probe_syncthing
+config=ClientConfig.load(Path(sys.argv[1]))
+sync_probe=probe_root(config.syncthing.local_root)
+probes=[probe_qbittorrent(config.qbittorrent),probe_syncthing(config.syncthing,sparse_supported=sync_probe.sparse_files)]
+print(json.dumps({"services":[{"service":p.service,"state":p.state,"detail":p.detail,"version":p.version,"device_id":p.device_id} for p in probes]},sort_keys=True))
+raise SystemExit(0 if all(p.state == 1 for p in probes) else 1)'''
+    result = subprocess.run(
+        ["docker", "exec", container, "python", "-c", program, config],
+        check=False, text=True, capture_output=True,
+    )
+    if result.returncode:
+        detail = result.stderr.strip() or result.stdout.strip() or "failed"
+        raise CheckFailure(f"client local-service probe failed: {detail}")
+    print(result.stdout.strip())
+
+
+def run_hardlink_probe(
+    container: str, qb_root: str, route_root: str, user: str | None = None,
+) -> None:
+    """Prove that the daemon can hard-link from qB data into automatic routes."""
+
+    program = r'''import os,sys,tempfile
+source_root,route_root=sys.argv[1:]
+source_path=None
+destination_path=None
+try:
+    source_fd,source_path=tempfile.mkstemp(prefix=".archive-control-preflight-",dir=source_root)
+    os.close(source_fd)
+    destination_fd,destination_path=tempfile.mkstemp(prefix=".archive-control-preflight-",dir=route_root)
+    os.close(destination_fd)
+    os.unlink(destination_path)
+    os.link(source_path,destination_path)
+    source_stat=os.stat(source_path)
+    destination_stat=os.stat(destination_path)
+    if source_stat.st_dev != destination_stat.st_dev or source_stat.st_ino != destination_stat.st_ino:
+        raise RuntimeError("link(2) did not produce the same filesystem inode")
+    print("hard-link staging probe passed")
+finally:
+    for path in (destination_path,source_path):
+        if path:
+            try:
+                os.unlink(path)
+            except FileNotFoundError:
+                pass
+'''
+    command = ["docker", "exec"]
+    if user:
+        command.extend(["--user", user])
+    command.extend([container, "python", "-c", program, qb_root, route_root])
+    result = subprocess.run(
+        command,
+        check=False, text=True, capture_output=True,
+    )
+    if result.returncode:
+        detail = result.stderr.strip() or result.stdout.strip() or "failed"
+        raise CheckFailure(f"hard-link staging probe failed: {detail}")
+    print(result.stdout.strip())
+
+
+def run_existing_route_directory_check(container: str, config: str) -> None:
+    """Reject a mount migration that hides an already configured route folder."""
+
+    program = r'''import json,os,sys
+from pathlib import Path,PurePosixPath
+from archive_clients.config import ClientConfig
+from archive_clients.syncthing import SyncthingHttp
+config=ClientConfig.load(Path(sys.argv[1]))
+transport=SyncthingHttp(config.syncthing)
+route_root=config.syncthing.api_root / "routes"
+missing=[]
+checked=[]
+for folder in transport.get_json("/rest/config").get("folders",[]):
+    if not isinstance(folder,dict) or not str(folder.get("label","")).startswith("archive-control:"):
+        continue
+    raw=folder.get("path")
+    if not isinstance(raw,str) or not raw:
+        continue
+    api=PurePosixPath(raw)
+    if api.parts and api.parts[0] == "~":
+        api=config.syncthing.api_root.joinpath(*api.parts[1:])
+    try:
+        api.relative_to(route_root)
+    except ValueError:
+        continue
+    local=config.syncthing.roots.api_to_local(api.as_posix())
+    checked.append(str(local))
+    if not local.is_dir():
+        missing.append({"folder_id":folder.get("id",""),"path":str(local)})
+print(json.dumps({"checked":checked,"missing":missing},sort_keys=True))
+raise SystemExit(1 if missing else 0)
+'''
+    result = subprocess.run(
+        ["docker", "exec", container, "python", "-c", program, config],
+        check=False, text=True, capture_output=True,
+    )
+    if result.returncode:
+        detail = result.stderr.strip() or result.stdout.strip() or "failed"
+        raise CheckFailure(
+            "an existing Archive Control Syncthing route directory is missing; "
+            f"complete the route-directory migration before starting jobs: {detail}"
+        )
+    print(result.stdout.strip())
+
+
+def main(argv: list[str] | None = None) -> int:
+    parser = argparse.ArgumentParser(
+        description="Read-only Archive Control Docker deployment preflight"
+    )
+    parser.add_argument("--client-config", type=Path, required=True,
+                        help="host path to client.toml")
+    parser.add_argument("--client-container", required=True)
+    parser.add_argument("--syncthing-container", required=True)
+    parser.add_argument("--qbittorrent-container", required=True)
+    parser.add_argument("--container-config", default="/etc/archive-control/client.toml",
+                        help="client.toml path inside the client container")
+    args = parser.parse_args(argv)
+    try:
+        client = docker_inspect(args.client_container)
+        syncthing = docker_inspect(args.syncthing_container)
+        qbittorrent = docker_inspect(args.qbittorrent_container)
+        configured_host_path = map_path(client, args.container_config).source
+        if configured_host_path.resolve(strict=False) != args.client_config.resolve(strict=False):
+            raise CheckFailure(
+                "--client-config does not match the file mounted into the client"
+            )
+        config = mounted_config(args.client_container, args.container_config)
+        qb = config["qbittorrent"]
+        sync = config["syncthing"]
+
+        client_qb = map_path(client, qb["local_root"])
+        client_route = map_path(client, route_local_path(sync))
+        syncthing_route = map_path(
+            syncthing, str(PurePosixPath(sync["api_root"]) / "routes")
+        )
+        qb_api = map_path(qbittorrent, qb["api_root"])
+        require_same_path(
+            "future Syncthing routes/local route mapping",
+            syncthing_route, client_route,
+        )
+        require_same_path("qBittorrent api_root/local_root", qb_api, client_qb)
+        if client_qb.destination != client_route.destination:
+            raise CheckFailure(
+                "qBittorrent and future route roots use separate client bind "
+                "mounts; hard-link staging would be unavailable"
+            )
+        run_hardlink_probe(
+            args.client_container, qb["local_root"], route_local_path(sync),
+            container_user(client),
+        )
+        run_existing_route_directory_check(
+            args.client_container, args.container_config
+        )
+        for key in ("shared_token_file",):
+            require_regular_secret(map_path(client, config[key]).source)
+        for service, key in ((qb, "password_file"), (sync, "api_key_file")):
+            require_regular_secret(map_path(client, service[key]).source)
+        run_client_check(args.client_container, args.container_config, "--check-config")
+        run_service_check(args.client_container, args.container_config)
+    except (CheckFailure, KeyError, OSError) as exc:
+        print(f"preflight failed: {exc}", file=sys.stderr)
+        return 1
+    print("preflight passed: bind mappings, hard-link staging, secrets, filesystem capabilities, and local APIs are healthy")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

scripts/publish-image.sh

@@ -0,0 +1,86 @@
+#!/usr/bin/env bash
+# Publish one complete Archive Control client OCI image index.
+set -euo pipefail
+
+usage() {
+  cat <<'EOF'
+Usage: scripts/publish-image.sh <semver> [--also-latest]
+
+Builds and pushes sodium/archive-clients for linux/amd64 and linux/arm64.
+Docker must already be authenticated to the target registry.
+EOF
+}
+
+if [[ $# -lt 1 || ${1:-} == '-h' || ${1:-} == '--help' ]]; then
+  usage
+  exit 2
+fi
+
+tag=$1
+shift
+also_latest=false
+if [[ ${1:-} == '--also-latest' ]]; then
+  also_latest=true
+  shift
+fi
+if [[ $# -ne 0 ]]; then
+  usage
+  exit 2
+fi
+
+repository=${IMAGE_REPOSITORY:-sodium/archive-clients}
+builder=${BUILDER:-archive-control-release}
+buildkit_image=${BUILDKIT_IMAGE:-moby/buildkit:rootless}
+# Nested Docker hosts can reject default OCI /proc mount masking. Rootless
+# BuildKit confines this compatibility flag to the disposable release builder.
+buildkitd_flags=${BUILDKITD_FLAGS:---oci-worker-no-process-sandbox}
+binfmt_image=${BINFMT_IMAGE:-tonistiigi/binfmt}
+host_arch=$(docker version --format '{{.Server.Arch}}')
+case ${host_arch} in
+  arm64|aarch64) emulated_arch=amd64 ;;
+  amd64|x86_64) emulated_arch=arm64 ;;
+  *) echo "Unsupported Docker server architecture: ${host_arch}" >&2; exit 1 ;;
+esac
+
+builder_created=false
+binfmt_installed=false
+cleanup() {
+  local status=$?
+  trap - EXIT
+  if [[ ${builder_created} == true ]]; then
+    docker buildx rm "${builder}" >/dev/null 2>&1 || true
+  fi
+  if [[ ${binfmt_installed} == true ]]; then
+    docker run --privileged --rm "${binfmt_image}" --uninstall "${emulated_arch}" \
+      >/dev/null 2>&1 || true
+  fi
+  exit "${status}"
+}
+trap cleanup EXIT
+
+docker run --privileged --rm "${binfmt_image}" --install "${emulated_arch}" \
+  >/dev/null
+binfmt_installed=true
+if docker buildx inspect "${builder}" >/dev/null 2>&1; then
+  docker buildx rm "${builder}" >/dev/null
+fi
+docker buildx create --name "${builder}" --driver docker-container \
+  --driver-opt "image=${buildkit_image}" \
+  --buildkitd-flags "${buildkitd_flags}" --use >/dev/null
+builder_created=true
+
+platforms=$(docker buildx inspect "${builder}" --bootstrap 2>&1)
+for platform in linux/amd64 linux/arm64; do
+  if ! grep -Fq "${platform}" <<<"${platforms}"; then
+    echo "Builder ${builder} does not support ${platform}; refusing partial release." >&2
+    exit 1
+  fi
+done
+
+tags=(--tag "${repository}:${tag}")
+if [[ ${also_latest} == true ]]; then
+  tags+=(--tag "${repository}:latest")
+fi
+docker buildx build --pull --platform linux/amd64,linux/arm64 \
+  --push "${tags[@]}" .
+docker buildx imagetools inspect "${repository}:${tag}"

src/archive_clients/__init__.py

@@ -1,4 +1,4 @@
 """Archive Control data-node daemon."""
 
-PROTO_COMMIT = "4ec852014dad74606d4078b3ae1aa208c814b033"
+PROTO_COMMIT = "03b6751d420e8e4e4cc9aeef4f76b13e28a7265f"
 

src/archive_clients/bencode.py

@@ -168,7 +168,7 @@ def _v1_files(info: dict[bytes, Any]) -> list[MetaFile]:
         components = [name] + [_component(part) for part in raw_path]
         result.append(MetaFile(
             "/".join(components), _length(item.get(b"length")),
-            _padding(item),
+            _padding(item) or _bitcomet_padding_name(components[-1]),
         ))
     return result
 
@@ -223,3 +223,13 @@ def _length(value: Any) -> int:
 def _padding(value: dict[bytes, Any]) -> bool:
     attributes = value.get(b"attr", b"")
     return isinstance(attributes, bytes) and b"p" in attributes
+
+
+def _bitcomet_padding_name(component: str) -> bool:
+    """Recognize BitComet's legacy padding-file convention.
+
+    Such v1 torrents often omit the standard ``attr=p`` flag, but
+    qBittorrent/libtorrent still hides these synthetic entries from its file
+    API.  The exact reserved prefix is the interoperable marker.
+    """
+    return component.startswith("_____padding_file_")

src/archive_clients/config.py

@@ -27,17 +27,28 @@ _ENV = re.compile(r"\$\{([A-Za-z_][A-Za-z0-9_]*)\}")
 class RootMapping:
     api_root: PurePosixPath
     local_root: Path
+    local_path_overrides: tuple[tuple[PurePosixPath, Path], ...] = ()
 
     def api_to_local(self, api_path: str) -> Path:
         candidate = PurePosixPath(api_path)
-        try:
+        for api_root, local_root in self.local_path_overrides:
-            relative = candidate.relative_to(self.api_root)
+            relative = _safe_relative(candidate, api_root)
-        except ValueError as exc:
+            if relative is not None:
-            raise ConfigError("API path is outside its configured root") from exc
+                return local_root.joinpath(*relative.parts)
-        if any(part in {"", ".", ".."} for part in relative.parts):
+        relative = _safe_relative(candidate, self.api_root)
-            raise ConfigError("API path contains an unsafe component")
+        if relative is None:
+            raise ConfigError("API path is outside its configured root")
         return self.local_root.joinpath(*relative.parts)
 
+    def local_root_for_api(self, api_path: str) -> Path:
+        candidate = PurePosixPath(api_path)
+        for api_root, local_root in self.local_path_overrides:
+            if _safe_relative(candidate, api_root) is not None:
+                return local_root
+        if _safe_relative(candidate, self.api_root) is None:
+            raise ConfigError("API path is outside its configured root")
+        return self.local_root
+
 
 @dataclass(frozen=True)
 class ServiceConfig:
@@ -48,10 +59,13 @@ class ServiceConfig:
     password_file: Path | None = None
     api_key_file: Path | None = None
     advertised_addresses: tuple[str, ...] = ()
+    local_path_overrides: tuple[tuple[PurePosixPath, Path], ...] = ()
 
     @property
     def roots(self) -> RootMapping:
-        return RootMapping(self.api_root, self.local_root)
+        return RootMapping(
+            self.api_root, self.local_root, self.local_path_overrides
+        )
 
     def read_password(self) -> str | None:
         return (
@@ -71,6 +85,7 @@ class ConnectionConfig:
     registration_timeout: float = 10
     heartbeat_interval: float = 15
     offline_timeout: float = 45
+    outbound_enqueue_timeout: float = 15
     reconnect_initial: float = 1
     reconnect_max: float = 60
     reconnect_reset_after: float = 60
@@ -82,7 +97,7 @@ class JobsConfig:
     stall_after: float = 30 * 60
     verification_timeout: float = 30 * 60
     poll_interval: float = 1
-    free_space_reserve_bytes: int = 1024 * 1024 * 1024
+    free_space_reserve_bytes: int = 32 * 1024 * 1024
 
 
 @dataclass(frozen=True)
@@ -160,7 +175,7 @@ def _service(value: Any, name: str) -> ServiceConfig:
         raise ConfigError(f"{name} must be a table")
     allowed = {
         "endpoint", "api_root", "local_root", "username", "password_file",
-        "api_key_file", "advertised_addresses",
+        "api_key_file", "advertised_addresses", "local_path_overrides",
     }
     _keys(value, allowed, name)
     api_root = PurePosixPath(_string(value, "api_root"))
@@ -182,6 +197,7 @@ def _service(value: Any, name: str) -> ServiceConfig:
         raise ConfigError("qbittorrent username and password_file are required")
     if name == "syncthing" and "api_key_file" not in value:
         raise ConfigError("syncthing api_key_file is required")
+    overrides = _local_path_overrides(value, api_root, name)
     return ServiceConfig(
         _endpoint(value, "endpoint", {"http", "https"}), api_root,
         _absolute_path(value, "local_root"), username,
@@ -189,15 +205,52 @@ def _service(value: Any, name: str) -> ServiceConfig:
         if "password_file" in value else None,
         _absolute_path(value, "api_key_file")
         if "api_key_file" in value else None,
-        tuple(addresses),
+        tuple(addresses), overrides,
     )
 
 
+def _local_path_overrides(
+    value: dict[str, Any], api_root: PurePosixPath, name: str
+) -> tuple[tuple[PurePosixPath, Path], ...]:
+    raw = value.get("local_path_overrides", {})
+    if name != "syncthing" and raw:
+        raise ConfigError(f"{name}.local_path_overrides is unsupported")
+    if not isinstance(raw, dict):
+        raise ConfigError(f"{name}.local_path_overrides must be a table")
+    parsed: list[tuple[PurePosixPath, Path]] = []
+    for raw_api_path, raw_local_path in raw.items():
+        if not isinstance(raw_api_path, str) or not isinstance(raw_local_path, str):
+            raise ConfigError(f"{name}.local_path_overrides entries must be strings")
+        candidate = PurePosixPath(raw_api_path)
+        if not candidate.is_absolute() or ".." in candidate.parts:
+            raise ConfigError(f"{name}.local_path_overrides API path is invalid")
+        if _safe_relative(candidate, api_root) is None:
+            raise ConfigError(f"{name}.local_path_overrides API path is outside root")
+        local = Path(raw_local_path)
+        if not local.is_absolute():
+            raise ConfigError(f"{name}.local_path_overrides local path is invalid")
+        parsed.append((candidate, local))
+    return tuple(sorted(parsed, key=lambda item: len(item[0].parts), reverse=True))
+
+
+def _safe_relative(
+    candidate: PurePosixPath, root: PurePosixPath
+) -> PurePosixPath | None:
+    try:
+        relative = candidate.relative_to(root)
+    except ValueError:
+        return None
+    if any(part in {"", ".", ".."} for part in relative.parts):
+        raise ConfigError("API path contains an unsafe component")
+    return relative
+
+
 def _connection(value: Any) -> ConnectionConfig:
     if not isinstance(value, dict):
         raise ConfigError("connection must be a table")
     _keys(value, {
         "registration_timeout", "heartbeat_interval", "offline_timeout",
+        "outbound_enqueue_timeout",
         "reconnect_initial", "reconnect_max", "reconnect_reset_after",
         "reconnect_jitter",
     }, "connection")
@@ -205,6 +258,9 @@ def _connection(value: Any) -> ConnectionConfig:
         registration_timeout=_duration(value.get("registration_timeout", "10s")),
         heartbeat_interval=_duration(value.get("heartbeat_interval", "15s")),
         offline_timeout=_duration(value.get("offline_timeout", "45s")),
+        outbound_enqueue_timeout=_duration(
+            value.get("outbound_enqueue_timeout", "15s")
+        ),
         reconnect_initial=_duration(value.get("reconnect_initial", "1s")),
         reconnect_max=_duration(value.get("reconnect_max", "60s")),
         reconnect_reset_after=_duration(value.get("reconnect_reset_after", "60s")),
@@ -214,6 +270,8 @@ def _connection(value: Any) -> ConnectionConfig:
         raise ConfigError("reconnect_initial cannot exceed reconnect_max")
     if result.offline_timeout <= result.heartbeat_interval:
         raise ConfigError("offline_timeout must exceed heartbeat_interval")
+    if result.outbound_enqueue_timeout <= 0:
+        raise ConfigError("outbound_enqueue_timeout must be positive")
     if not isinstance(result.reconnect_jitter, bool):
         raise ConfigError("reconnect_jitter must be boolean")
     return result
@@ -239,7 +297,7 @@ def _jobs(value: Any) -> JobsConfig:
         ),
         poll_interval=_duration(value.get("poll_interval", "1s")),
         free_space_reserve_bytes=_positive_int(
-            value.get("free_space_reserve_bytes", 1024 * 1024 * 1024),
+            value.get("free_space_reserve_bytes", 32 * 1024 * 1024),
             "jobs.free_space_reserve_bytes",
         ),
     )

src/archive_clients/daemon.py

@@ -11,6 +11,7 @@ from pathlib import Path, PurePosixPath
 from typing import Any
 
 from websockets.asyncio.client import connect
+from websockets.exceptions import ConnectionClosedOK
 
 from archive_clients.backup import SQLiteBackupManager
 from archive_clients.config import ClientConfig
@@ -42,6 +43,19 @@ from archive_control.v1 import (
 logger = logging.getLogger(__name__)
 
 
+def _job_id_for_command(command: control_pb2.Command) -> str:
+    """Return the durable job key for commands whose execution is serialized."""
+
+    payload = command.WhichOneof("payload")
+    if payload == "assign_job":
+        return command.assign_job.job.job_id
+    if payload == "execute_step":
+        return command.execute_step.job_id
+    if payload == "cancel_job":
+        return command.cancel_job.job_id
+    raise ValueError(f"command {command.command_id} does not execute a job")
+
+
 class ArchiveClientDaemon:
     def __init__(
         self,
@@ -94,7 +108,10 @@ class ArchiveClientDaemon:
         self._lease = DatabaseLease(config.state_db)
         self._active_route_commands: set[str] = set()
         self._active_job_commands: set[str] = set()
-        self._job_execution_lock = asyncio.Lock()
+        # Commands for one job remain ordered locally, while unrelated jobs
+        # may use the node's available qB/Syncthing/filesystem capacity in
+        # parallel. The control daemon owns admission policy.
+        self._job_execution_locks: dict[str, asyncio.Lock] = {}
         self.jobs = (
             ClientJobExecutor(
                 client_id=config.client_id,
@@ -197,7 +214,7 @@ class ArchiveClientDaemon:
                 raise RuntimeError("registration response correlation mismatch")
             if response.register_response.status != client_pb2.REGISTRATION_STATUS_ACCEPTED:
                 raise RuntimeError("control rejected registration")
-            if response.register_response.negotiated_version.major != 1:
+            if response.register_response.negotiated_version.major != 2:
                 raise RuntimeError("control negotiated an unsupported protocol version")
             logger.info("control_connection_registered")
             outbound: asyncio.Queue[str] = asyncio.Queue(maxsize=100)
@@ -205,7 +222,18 @@ class ArchiveClientDaemon:
             command_tasks: set[asyncio.Task[None]] = set()
             try:
                 await self._resume_commands(outbound, command_tasks)
-                async for frame in websocket:
+                # A proxy can leave the TCP/WebSocket socket apparently open
+                # after the control server has discarded its session.  The
+                # server then cannot deliver durable commands and its pending
+                # outbox remains stranded unless the client independently
+                # detects the missing application heartbeats and reconnects.
+                while True:
+                    try:
+                        frame = await self._next_frame(
+                            websocket, writer
+                        )
+                    except ConnectionClosedOK:
+                        return
                     await self._handle(decode(frame), outbound, command_tasks)
             finally:
                 writer.cancel()
@@ -290,6 +318,63 @@ class ArchiveClientDaemon:
         while True:
             await websocket.send(await outbound.get())
 
+    async def _next_frame(self, websocket: Any, writer: asyncio.Task[None]):
+        """Receive one frame while supervising the connection writer.
+
+        The previous receive-only wait let a failed writer go unnoticed until
+        the remote side happened to close or a heartbeat timeout elapsed.
+        Waiting for both directions makes a failed send an immediate,
+        reconnectable connection failure.
+        """
+
+        receiver = asyncio.create_task(websocket.recv())
+        try:
+            done, _ = await asyncio.wait(
+                {receiver, writer},
+                timeout=self.config.connection.offline_timeout,
+                return_when=asyncio.FIRST_COMPLETED,
+            )
+            if writer in done:
+                if not receiver.done():
+                    receiver.cancel()
+                    await asyncio.gather(receiver, return_exceptions=True)
+                if writer.cancelled():
+                    raise RuntimeError("control writer was cancelled")
+                error = writer.exception()
+                if error is not None:
+                    raise RuntimeError("control writer failed") from error
+                raise RuntimeError("control writer stopped")
+            if receiver not in done:
+                receiver.cancel()
+                await asyncio.gather(receiver, return_exceptions=True)
+                raise RuntimeError("control heartbeat timed out")
+            return receiver.result()
+        except BaseException:
+            if not receiver.done():
+                receiver.cancel()
+                await asyncio.gather(receiver, return_exceptions=True)
+            raise
+
+    async def _enqueue(
+        self, outbound: asyncio.Queue[str], message: str
+    ) -> None:
+        """Bound connection-local backpressure so a dead writer cannot wedge I/O.
+
+        A job event is durable before it is sent, so dropping this particular
+        connection after a bounded wait is safe: reconciliation/redelivery on
+        the next session will recover it.  In contrast, indefinitely waiting
+        for a full queue can prevent heartbeat acknowledgements from being
+        read or sent, which prevents the reconnect supervisor from running.
+        """
+
+        try:
+            await asyncio.wait_for(
+                outbound.put(message),
+                timeout=self.config.connection.outbound_enqueue_timeout,
+            )
+        except asyncio.TimeoutError as exc:
+            raise RuntimeError("control outbound queue is blocked") from exc
+
     async def _handle(
         self,
         envelope: Any,
@@ -301,13 +386,20 @@ class ArchiveClientDaemon:
             response = new_envelope()
             response.correlation_id = envelope.message_id
             response.heartbeat_ack.sequence = envelope.heartbeat.sequence
-            await outbound.put(encode(response))
+            await self._enqueue(outbound, encode(response))
         elif payload == "command":
             await self._accept_command(envelope, outbound, command_tasks)
         elif payload == "protocol_error":
             logger.warning(
                 "control_reported_protocol_error",
-                extra={"error_code": envelope.protocol_error.error.code},
+                extra={
+                    "error_code": envelope.protocol_error.error.code,
+                    "error_detail": envelope.protocol_error.error.message,
+                    "offending_message_id": (
+                        envelope.protocol_error.offending_message_id
+                    ),
+                    "retryable": envelope.protocol_error.error.retryable,
+                },
             )
 
     async def _accept_command(
@@ -348,6 +440,7 @@ class ArchiveClientDaemon:
                 if (
                     acknowledgement.status
                     == control_pb2.COMMAND_ACK_STATUS_ACCEPTED
+                    and accepted.state == "accepted"
                 ):
                     accepted_for_execution = True
                     acknowledgement.status = (
@@ -365,7 +458,7 @@ class ArchiveClientDaemon:
         response = new_envelope()
         response.correlation_id = envelope.message_id
         response.command_ack.CopyFrom(acknowledgement)
-        await outbound.put(encode(response))
+        await self._enqueue(outbound, encode(response))
 
         if (
             accepted is not None
@@ -386,7 +479,7 @@ class ArchiveClientDaemon:
                 job_snapshot.last_event_sequence = int(
                     row["last_event_sequence"]
                 )
-                await outbound.put(encode(snapshot))
+                await self._enqueue(outbound, encode(snapshot))
         elif (
             accepted is not None
             and accepted_for_execution
@@ -433,13 +526,28 @@ class ArchiveClientDaemon:
                 outbound,
                 command_tasks,
             )
+        elif (
+            accepted is not None
+            and accepted_for_execution
+            and command.WhichOneof("payload") == "reconcile_job"
+        ):
+            reconciliation = command.reconcile_job
+            await asyncio.to_thread(
+                self.store.reconcile_job,
+                job_id=reconciliation.authoritative_job.definition.job_id,
+                definition_json=encode_message(reconciliation.authoritative_job.definition),
+                state=job_pb2.JobState.Name(reconciliation.authoritative_job.state),
+                revision=reconciliation.authoritative_job.revision,
+                last_event_sequence=reconciliation.authoritative_last_event_sequence,
+                committed=reconciliation.authoritative_job.committed,
+                superseded_command_ids=list(reconciliation.superseded_command_ids),
+            )
 
     async def _resume_commands(
         self,
         outbound: asyncio.Queue[str],
         command_tasks: set[asyncio.Task[None]],
     ) -> None:
-        job_commands: list[control_pb2.Command] = []
         for row in await asyncio.to_thread(self.store.list_accepted_commands):
             acknowledgement = decode_message(
                 str(row["acknowledgement_json"]), control_pb2.CommandAck()
@@ -451,28 +559,14 @@ class ArchiveClientDaemon:
             )
             if command.WhichOneof("payload") == "ensure_route":
                 self._schedule_route_command(
-                    command, "", outbound, command_tasks
+                    command, "", outbound, command_tasks, restore_ready=True
                 )
-            elif (
+            # Job commands are intentionally not replayed here.  A command
-                command.WhichOneof("payload") in {
+            # acknowledgement is durable on both sides; the control daemon
-                    "assign_job", "execute_step", "cancel_job"
+            # redelivers an unacknowledged command, while registration
-                }
+            # reconciliation requests snapshots for active jobs.  Replaying
-                and self.jobs is not None
+            # every historical command re-emits overlapping event ranges and
-            ):
+            # can flood the single connection's bounded outbound queue.
-                if command.WhichOneof("payload") == "cancel_job":
-                    self.jobs.request_cancel(command.cancel_job.job_id)
-                job_commands.append(command)
-        if job_commands:
-            task = asyncio.create_task(
-                self._resume_job_commands(job_commands, outbound),
-                name="resume-job-commands",
-            )
-            command_tasks.add(task)
-            task.add_done_callback(
-                lambda completed: self._command_finished(
-                    completed, command_tasks
-                )
-            )
 
     async def _resume_route_commands(
         self,
@@ -543,7 +637,9 @@ class ArchiveClientDaemon:
         correlation_id: str,
         outbound: asyncio.Queue[str],
     ) -> None:
-        async with self._job_execution_lock:
+        job_id = _job_id_for_command(command)
+        lock = self._job_execution_locks.setdefault(job_id, asyncio.Lock())
+        async with lock:
             await self._execute_job_command_locked(
                 command, correlation_id, outbound
             )
@@ -565,34 +661,46 @@ class ArchiveClientDaemon:
             loop = asyncio.get_running_loop()
 
             def emit(event):
+                if not self.store.is_command_active(command.command_id):
+                    # Reconciliation retired this lease while its blocking
+                    # worker was still unwinding. Its durable local record is
+                    # not allowed to re-enter the control event stream.
+                    return
                 response = new_envelope()
                 response.correlation_id = correlation_id
                 response.job_event.CopyFrom(event)
                 future = asyncio.run_coroutine_threadsafe(
-                    outbound.put(encode(response)), loop
+                    self._enqueue(outbound, encode(response)), loop
                 )
                 try:
-                    future.result(timeout=30)
+                    future.result(
+                        timeout=self.config.connection.outbound_enqueue_timeout
+                        + 1
+                    )
                 except Exception:
                     # The event is already durable in the client DB and will
                     # be replayed after reconnect.
                     pass
 
             events = await asyncio.to_thread(
-                self.jobs.execute, command.execute_step, emit
+                self.jobs.execute, command.execute_step, emit, command.command_id
             )
             streamed = True
         elif payload == "cancel_job":
             events = await asyncio.to_thread(
-                self.jobs.cancel, command.cancel_job
+                self.jobs.cancel, command.cancel_job, command.command_id
             )
         else:
             raise JobExecutionError("job command payload is unsupported")
         for event in (() if streamed else events):
+            if not await asyncio.to_thread(
+                self.store.is_command_active, command.command_id
+            ):
+                return
             response = new_envelope()
             response.correlation_id = correlation_id
             response.job_event.CopyFrom(event)
-            await outbound.put(encode(response))
+            await self._enqueue(outbound, encode(response))
 
     def _schedule_route_command(
         self,
@@ -600,12 +708,15 @@ class ArchiveClientDaemon:
         correlation_id: str,
         outbound: asyncio.Queue[str],
         command_tasks: set[asyncio.Task[None]],
+        restore_ready: bool = False,
     ) -> None:
         if command.command_id in self._active_route_commands:
             return
         self._active_route_commands.add(command.command_id)
         task = asyncio.create_task(
-            self._execute_route(command, correlation_id, outbound),
+            self._execute_route(
+                command, correlation_id, outbound, restore_ready=restore_ready
+            ),
             name=f"route-{command.ensure_route.route.route_id}",
         )
         command_tasks.add(task)
@@ -636,13 +747,14 @@ class ArchiveClientDaemon:
             response = new_envelope()
             response.correlation_id = correlation_id
             response.inventory_chunk.CopyFrom(chunk)
-            await outbound.put(encode(response))
+            await self._enqueue(outbound, encode(response))
 
     async def _execute_route(
         self,
         command: Any,
         correlation_id: str,
         outbound: asyncio.Queue[str],
+        restore_ready: bool = False,
     ) -> None:
         assert self.routes is not None
         spec = command.ensure_route.route
@@ -661,8 +773,21 @@ class ArchiveClientDaemon:
             response.route_update.CopyFrom(
                 decode_message(str(row["update_json"]), control_pb2.RouteUpdate())
             )
-            await outbound.put(encode(response))
+            await self._enqueue(outbound, encode(response))
-        if attempt["state"] in {"ready", "failed"}:
+        if attempt["state"] == "ready":
+            if restore_ready:
+                # Route readiness is durable, but this process-local lookup is
+                # not. Reconfigure (which validates the existing Syncthing
+                # folder and recreates its local directory if necessary) after
+                # a daemon restart, before replaying stored READY updates.
+                configured = await asyncio.to_thread(
+                    self.routes.configure,
+                    spec,
+                    time.monotonic() + spec.setup_timeout_seconds,
+                )
+                self._known_route_paths[spec.route_id] = configured.local_path
+            return
+        if attempt["state"] == "failed":
             return
 
         deadline = time.monotonic() + spec.setup_timeout_seconds
@@ -813,7 +938,7 @@ class ArchiveClientDaemon:
         response = new_envelope()
         response.correlation_id = correlation_id
         response.route_update.CopyFrom(update)
-        await outbound.put(encode(response))
+        await self._enqueue(outbound, encode(response))
 
     def _local_route(
         self, spec: route_pb2.EnsureRouteSpec, state: int
@@ -940,6 +1065,17 @@ class ArchiveClientDaemon:
                 acknowledgement.error.message = "job assignment is invalid"
             else:
                 acknowledgement.status = control_pb2.COMMAND_ACK_STATUS_ACCEPTED
+        elif command.WhichOneof("payload") == "reconcile_job":
+            record = command.reconcile_job.authoritative_job
+            if (
+                not record.definition.job_id
+                or command.reconcile_job.authoritative_last_event_sequence < 0
+            ):
+                acknowledgement.status = control_pb2.COMMAND_ACK_STATUS_REJECTED
+                acknowledgement.error.code = common_pb2.ERROR_CODE_INVALID_ARGUMENT
+                acknowledgement.error.message = "job reconciliation is invalid"
+            else:
+                acknowledgement.status = control_pb2.COMMAND_ACK_STATUS_ACCEPTED
         elif command.WhichOneof("payload") == "execute_step":
             step = command.execute_step
             if self.jobs is None:

src/archive_clients/jobs.py

@@ -4,12 +4,15 @@ from __future__ import annotations
 
 import hashlib
 import json
+import logging
+import os
 import shutil
+import stat
 import threading
 import time
 import uuid
 from pathlib import Path, PurePosixPath
-from typing import Callable
+from typing import Callable, Iterable
 
 from archive_clients.protocol import decode_message, encode_message
 from archive_clients.eviction import (
@@ -25,10 +28,11 @@ from archive_clients.qbittorrent import (
 )
 from archive_clients.resources import NormalizedResource
 from archive_clients.state import ClientStore
-from archive_clients.syncthing import SyncthingTransferObserver
+from archive_clients.syncthing import RouteSetupError, SyncthingTransferObserver
 from archive_clients.transfer import (
     TransferError,
     TransferIntegrityError,
+    cleanup_partial_transfer,
     cleanup_transfer,
     load_published_transfer,
     materialize_transfer,
@@ -51,6 +55,9 @@ class JobCancelled(JobExecutionError):
     pass
 
 
+logger = logging.getLogger(__name__)
+
+
 class ClientJobExecutor:
     def __init__(
         self,
@@ -65,7 +72,7 @@ class ClientJobExecutor:
         sparse_supported: bool,
         poll_interval: float = 1,
         verification_timeout: float = 30 * 60,
-        free_space_reserve_bytes: int = 1024 * 1024 * 1024,
+        free_space_reserve_bytes: int = 32 * 1024 * 1024,
     ):
         self.client_id = client_id
         self.qbittorrent = qbittorrent
@@ -79,6 +86,8 @@ class ClientJobExecutor:
         self.verification_timeout = verification_timeout
         self.free_space_reserve_bytes = free_space_reserve_bytes
         self._cancel_events: dict[str, threading.Event] = {}
+        self._execution_locks: dict[str, threading.Lock] = {}
+        self._execution_locks_guard = threading.Lock()
 
     def request_cancel(self, job_id: str) -> None:
         self._cancel_events.setdefault(job_id, threading.Event()).set()
@@ -88,32 +97,45 @@ class ClientJobExecutor:
     ) -> list[control_pb2.JobEvent]:
         definition = command.job
         self._validate_definition(definition)
-        replay = self._replay(
+        self.store.ensure_job_definition(
-            definition.job_id, command.expected_last_event_sequence
+            definition.job_id, encode_message(definition)
         )
-        if replay:
+        # Assignment succeeds through CommandAck. It must not let a client
-            return replay
+        # allocate a globally ordered JobEvent cursor.
-        event = self._event(
+        return []
-            definition,
-            sequence=command.expected_last_event_sequence + 1,
-            revision=command.expected_job_revision,
-            event_type=control_pb2.JOB_EVENT_TYPE_ASSIGNED,
-            state=job_pb2.JOB_STATE_PREPARING,
-            committed=False,
-        )
-        self._record(definition, event)
-        return [event]
 
     def execute(
         self,
         command: control_pb2.ExecuteStepCommand,
         event_callback: Callable[[control_pb2.JobEvent], None] | None = None,
+        command_id: str = "",
+    ) -> list[control_pb2.JobEvent]:
+        # asyncio cancellation of a connection-bound task cannot stop the
+        # synchronous filesystem/qB operation already running in its worker
+        # thread. A replay after reconnect therefore waits for that operation
+        # and then reads its durable event journal instead of executing twice.
+        with self._execution_lock(command.job_id):
+            return self._execute_locked(command, event_callback, command_id)
+
+    def _execution_lock(self, job_id: str) -> threading.Lock:
+        with self._execution_locks_guard:
+            return self._execution_locks.setdefault(job_id, threading.Lock())
+
+    def _execute_locked(
+        self,
+        command: control_pb2.ExecuteStepCommand,
+        event_callback: Callable[[control_pb2.JobEvent], None] | None = None,
+        command_id: str = "",
     ) -> list[control_pb2.JobEvent]:
         definition = self._definition(command.job_id)
         replay = self._replay(
             command.job_id, command.expected_last_event_sequence
         )
-        if replay and replay[-1].type in {
+        step_replay = [
+            event for event in replay
+            if event.progress.step == command.step
+        ]
+        if step_replay and step_replay[-1].type in {
             control_pb2.JOB_EVENT_TYPE_STEP_SUCCEEDED,
             control_pb2.JOB_EVENT_TYPE_COMMITTED,
             control_pb2.JOB_EVENT_TYPE_SUCCEEDED,
@@ -125,32 +147,52 @@ class ClientJobExecutor:
                 for event in replay:
                     event_callback(event)
             return replay
-        started = replay[0] if replay else self._event(
+        if step_replay:
-            definition,
+            started = step_replay[0]
-            sequence=command.expected_last_event_sequence + 1,
+            cursor = step_replay[-1]
-            revision=command.expected_job_revision + 1,
+            emitted = list(step_replay)
-            event_type=control_pb2.JOB_EVENT_TYPE_STEP_STARTED,
+        else:
-            state=job_pb2.JOB_STATE_RUNNING,
+            previous = replay[-1] if replay else None
-            committed=(
+            started = self._event(
-                self._committed(command.job_id)
+                definition,
-                or command.step == job_pb2.JOB_STEP_KIND_STAGING_CLEANUP
+                sequence=(
-                or (
+                    previous.sequence + 1
-                    command.step == job_pb2.JOB_STEP_KIND_SAFE_FILE_UNLINK
+                    if previous is not None
-                    and self.store.get_job_artifact(
+                    else command.expected_last_event_sequence + 1
-                        command.job_id, "qb-entry-removed"
+                ),
-                    ) is not None
+                revision=(
-                )
+                    previous.job_revision + 1
-            ),
+                    if previous is not None
-            step=command.step,
+                    else command.expected_job_revision + 1
-            step_state=job_pb2.STEP_STATE_RUNNING,
+                ),
-        )
+                event_type=control_pb2.JOB_EVENT_TYPE_STEP_STARTED,
-        if not replay:
+                state=job_pb2.JOB_STATE_RUNNING,
+                committed=(
+                    self._committed(command.job_id)
+                    or command.step == job_pb2.JOB_STEP_KIND_STAGING_CLEANUP
+                    or (
+                        command.step == job_pb2.JOB_STEP_KIND_SAFE_FILE_UNLINK
+                        and self.store.get_job_artifact(
+                            command.job_id, "qb-entry-removed"
+                        ) is not None
+                    )
+                ),
+                step=command.step,
+                step_state=job_pb2.STEP_STATE_RUNNING,
+                command_id=command_id,
+            )
             self._record(definition, started)
+            cursor = started
+            emitted = [started]
         if event_callback is not None:
-            event_callback(started)
+            for event in emitted:
-        emitted = [started]
+                event_callback(event)
-        cursor = started
+        # A newly-started step must publish its first observation.  In
-        speed_sample = [time.monotonic(), 0]
+        # particular, a sparse Syncthing temporary file may retain the same
+        # allocated-block count for a long time while data is still needed;
+        # suppressing that first observation made a healthy transfer look
+        # permanently stalled to the control daemon.
+        speed_sample: list[float | int | None] = [None, 0]
 
         def progress(
             fraction: float,
@@ -160,8 +202,12 @@ class ClientJobExecutor:
         ) -> None:
             nonlocal cursor
             now = time.monotonic()
-            elapsed = now - float(speed_sample[0])
+            previous_time = speed_sample[0]
-            if fraction < 1 and elapsed < 1:
+            elapsed = (
+                now - float(previous_time)
+                if previous_time is not None else 0.0
+            )
+            if previous_time is not None and fraction < 1 and elapsed < 1:
                 return
             speed = (
                 max(0, bytes_complete - int(speed_sample[1])) / elapsed
@@ -176,6 +222,7 @@ class ClientJobExecutor:
                 committed=cursor.committed,
                 step=command.step,
                 step_state=job_pb2.STEP_STATE_RUNNING,
+                command_id=command_id,
             )
             event.progress.fraction_complete = max(
                 0.0, min(float(fraction), 1.0)
@@ -206,6 +253,7 @@ class ClientJobExecutor:
                 committed=started.committed,
                 step=command.step,
                 step_state=job_pb2.STEP_STATE_CANCELLED,
+                command_id=command_id,
             )
             cancelling.error.code = common_pb2.ERROR_CODE_CANCELLED
             cancelling.error.message = str(error)
@@ -263,6 +311,7 @@ class ClientJobExecutor:
                 committed=started.committed,
                 step=command.step,
                 step_state=job_pb2.STEP_STATE_FAILED,
+                command_id=command_id,
             )
             failed.error.code = _job_error_code(error)
             failed.error.message = str(error) or type(error).__name__
@@ -305,6 +354,7 @@ class ClientJobExecutor:
             committed=committed,
             step=command.step,
             step_state=job_pb2.STEP_STATE_SUCCEEDED,
+            command_id=command_id,
         )
         if result is not None:
             succeeded.observed_placement.CopyFrom(result)
@@ -315,7 +365,7 @@ class ClientJobExecutor:
         return emitted
 
     def cancel(
-        self, command: control_pb2.CancelJobCommand
+        self, command: control_pb2.CancelJobCommand, command_id: str = ""
     ) -> list[control_pb2.JobEvent]:
         definition = self._definition(command.job_id)
         self.request_cancel(command.job_id)
@@ -366,6 +416,7 @@ class ClientJobExecutor:
             committed=committed,
             step=job_pb2.JOB_STEP_KIND_ROLLBACK,
             step_state=job_pb2.STEP_STATE_SUCCEEDED,
+            command_id=command_id,
         )
         if placement is not None:
             event.observed_placement.CopyFrom(placement)
@@ -541,15 +592,29 @@ class ClientJobExecutor:
             sha256_hex=hashlib.sha256(resource.metainfo_bytes).hexdigest(),
         )
         del artifact
+        route_root = self.route_path(definition.transfer.route_id)
+        # Staging is normally zero-copy when qB's data root and the paired
+        # Syncthing route share a filesystem.  Do not reserve the complete
+        # logical payload in that case: FileMaterializer will use link(2),
+        # which consumes only directory/inode metadata.  Retain the metainfo
+        # allowance and reserve, and account for any source files that really
+        # must fall back to a data-copy path.
         self._require_space(
-            self.route_path(definition.transfer.route_id),
+            route_root,
-            definition.transfer.transfer_delta_logical_bytes
+            self._copy_required_bytes(
+                self.qb_root,
+                route_root,
+                (
+                    (entry.target_canonical_path, entry.logical_bytes)
+                    for entry in manifest.files
+                ),
+            )
             + len(resource.metainfo_bytes),
         )
         stage_transfer(
             manifest,
             source_root=self.qb_root,
-            sync_root=self.route_path(definition.transfer.route_id),
+            sync_root=route_root,
             store=self.store,
             artifact_sources={"metainfo/source.torrent": metainfo_path},
             sparse_supported=self.sparse_supported,
@@ -563,7 +628,17 @@ class ClientJobExecutor:
                 f"staged {completed} of {total} bytes",
             ),
         )
-        self._observer(definition).rescan()
+        try:
+            self._observer(definition).rescan()
+        except RouteSetupError as exc:
+            # A manual Syncthing scan may take longer than the bounded REST
+            # request timeout for a large newly linked file. The folder watch
+            # and the following transfer observation still converge, so do
+            # not roll back an otherwise durable staged transfer.
+            logger.warning("syncthing_rescan_deferred", extra={
+                "job_id": definition.job_id,
+                "error_type": type(exc).__name__,
+            })
 
     def _wait_for_syncthing(
         self,
@@ -595,6 +670,15 @@ class ClientJobExecutor:
                 # Syncthing can expose the per-job directory before the
                 # ready marker and manifest have arrived atomically as a set.
                 pass
+            except RouteSetupError as exc:
+                # A network interruption can temporarily make the local
+                # Syncthing REST API unavailable.  The staged payload is
+                # durable and the job must remain recoverable; keep polling
+                # instead of turning a transient outage into a failed job.
+                logger.warning("syncthing_status_deferred", extra={
+                    "job_id": definition.job_id,
+                    "error_type": type(exc).__name__,
+                })
             time.sleep(self.poll_interval)
 
     def _target_materialize(
@@ -607,9 +691,18 @@ class ClientJobExecutor:
                 "target materialization was sent to the wrong client"
             )
         published = load_published_transfer(self._job_directory(definition))
+        # The target can likewise hardlink an arrived Syncthing payload into
+        # qB's content root when those directories share a filesystem.
         self._require_space(
             self.qb_root,
-            definition.transfer.transfer_delta_logical_bytes,
+            self._copy_required_bytes(
+                published.job_directory,
+                self.qb_root,
+                (
+                    (entry.payload_relative_path, entry.logical_bytes)
+                    for entry in published.manifest.files
+                ),
+            ),
         )
         info_hash = _info_hash(definition)
         resource = self.qbittorrent.get_resource(info_hash)
@@ -794,6 +887,11 @@ class ClientJobExecutor:
             qb_root=job_directory,
             store=self.store,
         )
+        cleanup_partial_transfer(
+            job_directory,
+            job_id=definition.job_id,
+            store=self.store,
+        )
         for name in ("ready.json", "manifest.json"):
             candidate = job_directory / name
             if candidate.is_file() and not candidate.is_symlink():
@@ -843,6 +941,37 @@ class ClientJobExecutor:
                 f"{required} bytes required including reserve"
             )
 
+    @staticmethod
+    def _copy_required_bytes(
+        source_root: Path,
+        destination_root: Path,
+        files: Iterable[tuple[str, int]],
+    ) -> int:
+        """Return logical bytes that cannot be materialized by hardlink.
+
+        A hardlink is possible only for regular files on the destination
+        filesystem.  Conservatively charge a file when it cannot be inspected;
+        the normal materializer will then provide the precise integrity error.
+        """
+
+        destination_device = destination_root.stat().st_dev
+        required = 0
+        for relative_path, logical_bytes in files:
+            relative = PurePosixPath(relative_path)
+            source = source_root.joinpath(*relative.parts)
+            try:
+                metadata = source.stat(follow_symlinks=False)
+            except OSError:
+                required += logical_bytes
+                continue
+            if (
+                not stat.S_ISREG(metadata.st_mode)
+                or metadata.st_dev != destination_device
+                or _mount_id(source) != _mount_id(destination_root)
+            ):
+                required += logical_bytes
+        return required
+
     def _observer(
         self, definition: job_pb2.JobDefinition
     ) -> SyncthingTransferObserver:
@@ -920,6 +1049,7 @@ class ClientJobExecutor:
         committed: bool,
         step: int = job_pb2.JOB_STEP_KIND_UNSPECIFIED,
         step_state: int = job_pb2.STEP_STATE_UNSPECIFIED,
+        command_id: str = "",
     ) -> control_pb2.JobEvent:
         event = control_pb2.JobEvent(
             event_id=str(uuid.uuid4()),
@@ -929,6 +1059,7 @@ class ClientJobExecutor:
             type=event_type,
             state=state,
             committed=committed,
+            command_id=command_id,
         )
         event.occurred_at.GetCurrentTime()
         if step != job_pb2.JOB_STEP_KIND_UNSPECIFIED:
@@ -1089,6 +1220,8 @@ def _job_error_code(error: Exception) -> int:
         return common_pb2.ERROR_CODE_INTEGRITY_CHECK_FAILED
     if isinstance(error, PermissionError):
         return common_pb2.ERROR_CODE_PERMISSION_DENIED
+    if isinstance(error, RouteSetupError):
+        return common_pb2.ERROR_CODE_UNAVAILABLE
     if isinstance(error, JobExecutionError):
         return common_pb2.ERROR_CODE_PRECONDITION_FAILED
     if isinstance(error, TransferError):
@@ -1096,3 +1229,41 @@ def _job_error_code(error: Exception) -> int:
     if isinstance(error, EvictionError):
         return common_pb2.ERROR_CODE_PRECONDITION_FAILED
     return common_pb2.ERROR_CODE_INTERNAL
+
+
+def _mount_id(path: Path) -> str | None:
+    """Return Linux's effective mount ID for a path when procfs is available.
+
+    Bind mounts can share ``st_dev`` while still rejecting ``link(2)`` with
+    ``EXDEV``.  Mount IDs distinguish that case without creating probe files
+    inside a Syncthing folder.
+    """
+
+    try:
+        target = os.path.realpath(path)
+        best: tuple[int, str] | None = None
+        with open("/proc/self/mountinfo", encoding="utf-8") as source:
+            for line in source:
+                fields = line.rstrip("\n").split(" ")
+                if len(fields) < 5:
+                    continue
+                mountpoint = _unescape_mount_path(fields[4])
+                if target != mountpoint and not target.startswith(
+                    mountpoint.rstrip("/") + "/"
+                ):
+                    continue
+                candidate = (len(mountpoint), fields[0])
+                if best is None or candidate[0] > best[0]:
+                    best = candidate
+        return None if best is None else best[1]
+    except OSError:
+        return None
+
+
+def _unescape_mount_path(value: str) -> str:
+    return (
+        value.replace("\\040", " ")
+        .replace("\\011", "\t")
+        .replace("\\012", "\n")
+        .replace("\\134", "\\")
+    )

src/archive_clients/protocol.py

@@ -18,7 +18,7 @@ class ProtocolError(ValueError):
 
 def new_envelope() -> envelope_pb2.Envelope:
     envelope = envelope_pb2.Envelope()
-    envelope.protocol_version.major = 1
+    envelope.protocol_version.major = 2
     envelope.message_id = str(uuid.uuid4())
     envelope.sent_at.FromDatetime(datetime.now(timezone.utc))
     return envelope
@@ -59,7 +59,7 @@ def decode(data: str | bytes, max_bytes: int = 1024 * 1024) -> envelope_pb2.Enve
         json_format.ParseError,
     ) as exc:
         raise ProtocolError("invalid control envelope") from exc
-    if envelope.protocol_version.major != 1:
+    if envelope.protocol_version.major != 2:
         raise ProtocolError("unsupported protocol major version")
     _canonical_uuid(envelope.message_id, "message_id")
     if envelope.correlation_id:

src/archive_clients/qbittorrent.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import json
+import logging
 import threading
 import time
 import uuid
@@ -16,6 +17,8 @@ from urllib import error, parse, request
 from archive_clients.config import ServiceConfig
 from archive_clients.resources import NormalizedResource, normalize_resource
 
+logger = logging.getLogger(__name__)
+
 
 class QBittorrentError(RuntimeError):
     pass
@@ -72,7 +75,17 @@ class QBittorrentReader:
             torrent_hash = torrent.get("hash")
             if not isinstance(torrent_hash, str):
                 raise QBittorrentError("qBittorrent torrent hash is invalid")
-            result.append(self._normalize(torrent, torrent_hash))
+            try:
+                result.append(self._normalize(torrent, torrent_hash))
+            except ValueError as exc:
+                # A stale or malformed qBittorrent entry must not hide every
+                # otherwise valid resource from Archive/Evict inventory.
+                # Keep it ineligible and leave an operator-visible diagnosis.
+                logger.warning(
+                    "Skipping qBittorrent resource with inconsistent "
+                    "metadata: hash=%s name=%r reason=%s",
+                    torrent_hash, torrent.get("name"), exc,
+                )
         return result
 
     def get_resource(self, torrent_hash: str) -> NormalizedResource | None:

src/archive_clients/resources.py

@@ -91,12 +91,21 @@ def normalize_resource(
     observed_at: datetime | None = None,
 ) -> NormalizedResource:
     metainfo = decode_metainfo(metainfo_bytes)
-    if len(raw_files) != len(metainfo.files):
+    # qBittorrent/libtorrent may omit torrent padding files from
+    # /torrents/files while keeping them in the exported metainfo.
+    visible_metainfo_files = tuple(
+        item for item in metainfo.files if not item.padding
+    )
+    if len(raw_files) == len(metainfo.files):
+        matched_metainfo_files = metainfo.files
+    elif len(raw_files) == len(visible_metainfo_files):
+        matched_metainfo_files = visible_metainfo_files
+    else:
         raise ResourceError("qBittorrent and metainfo file counts differ")
     files = []
     canonical = True
     for expected_index, (raw, meta_file) in enumerate(
-        zip(raw_files, metainfo.files, strict=True)
+        zip(raw_files, matched_metainfo_files, strict=True)
     ):
         index = _integer(raw.get("index"), "file index")
         if index != expected_index:

src/archive_clients/routes.py

@@ -37,7 +37,9 @@ def discover_routes(
             relative = normalized_api_path.relative_to(roots.api_root)
         except (ConfigError, ValueError):
             continue
-        if not _lexically_within(local_path, roots.local_root):
+        if not _lexically_within(
+            local_path, roots.local_root_for_api(normalized_api_path.as_posix())
+        ):
             continue
         if relative == PurePosixPath("."):
             continue

src/archive_clients/state.py

@@ -7,6 +7,8 @@ import json
 import os
 import sqlite3
 import stat
+import threading
+from contextlib import contextmanager
 from dataclasses import dataclass
 from pathlib import Path
 
@@ -14,6 +16,12 @@ from pathlib import Path
 SCHEMA_VERSION = 3
 
 
+# A client daemon executes unrelated jobs concurrently.  SQLite still permits
+# only one writer, so serialize this process's short state transactions rather
+# than allowing an otherwise healthy job to fail after its busy timeout.
+_DATABASE_LOCK = threading.RLock()
+
+
 class CommandConflict(RuntimeError):
     pass
 
@@ -30,6 +38,7 @@ class FileOperationConflict(RuntimeError):
 class CommandAcceptance:
     duplicate: bool
     acknowledgement_json: str
+    state: str
 
 
 class ClientStore:
@@ -77,7 +86,7 @@ class ClientStore:
             connection.execute("BEGIN IMMEDIATE")
             existing = connection.execute(
                 """
-                SELECT payload_sha256, command_json, acknowledgement_json
+                SELECT payload_sha256, command_json, acknowledgement_json, state
                 FROM commands WHERE command_id = ?
                 """,
                 (command_id,),
@@ -85,17 +94,26 @@ class ClientStore:
             if existing:
                 if existing["payload_sha256"] != digest or existing["command_json"] != payload:
                     raise CommandConflict("command ID was reused with different content")
-                return CommandAcceptance(True, existing["acknowledgement_json"])
+                return CommandAcceptance(
+                    True, existing["acknowledgement_json"], existing["state"]
+                )
+            status = json.loads(acknowledgement).get("status")
+            state = (
+                "rejected"
+                if status is not None
+                and status != "COMMAND_ACK_STATUS_ACCEPTED"
+                else "accepted"
+            )
             connection.execute(
                 """
                 INSERT INTO commands (
                     command_id, payload_sha256, command_json,
                     acknowledgement_json, state
-                ) VALUES (?, ?, ?, ?, 'received')
+                ) VALUES (?, ?, ?, ?, ?)
                 """,
-                (command_id, digest, payload, acknowledgement),
+                (command_id, digest, payload, acknowledgement, state),
             )
-        return CommandAcceptance(False, acknowledgement)
+        return CommandAcceptance(False, acknowledgement, state)
 
     def list_active_job_cursors(self) -> list[dict[str, object]]:
         with self._connect() as connection:
@@ -114,7 +132,7 @@ class ClientStore:
             rows = connection.execute(
                 """
                 SELECT command_id, command_json, acknowledgement_json
-                FROM commands ORDER BY rowid
+                FROM commands WHERE state = 'accepted' ORDER BY rowid
                 """
             ).fetchall()
         return [dict(row) for row in rows]
@@ -191,6 +209,91 @@ class ClientStore:
                 ),
             )
 
+    def ensure_job_definition(self, job_id: str, definition_json: str) -> None:
+        """Durably record an assignment without inventing a global event."""
+        definition = _canonical(json.loads(definition_json))
+        with self._connect() as connection:
+            connection.execute("BEGIN IMMEDIATE")
+            existing = connection.execute(
+                "SELECT definition_json FROM jobs WHERE job_id = ?", (job_id,)
+            ).fetchone()
+            if existing is not None:
+                if existing["definition_json"] != definition:
+                    raise JobConflict("job definition is immutable")
+                return
+            connection.execute(
+                """
+                INSERT INTO jobs (job_id, definition_json, state, revision,
+                                  last_event_sequence, committed)
+                VALUES (?, ?, 'JOB_STATE_QUEUED', 0, 0, 0)
+                """,
+                (job_id, definition),
+            )
+
+    def is_command_active(self, command_id: str) -> bool:
+        with self._connect() as connection:
+            row = connection.execute(
+                "SELECT state FROM commands WHERE command_id = ?", (command_id,)
+            ).fetchone()
+        return row is not None and row["state"] == "accepted"
+
+    def reconcile_job(
+        self,
+        *,
+        job_id: str,
+        definition_json: str,
+        state: str,
+        revision: int,
+        last_event_sequence: int,
+        committed: bool,
+        superseded_command_ids: list[str],
+    ) -> None:
+        """Apply control's cursor, retiring only stale command leases.
+
+        This drops unacknowledged local journal rows beyond control's cursor;
+        resource files and operation artifacts are intentionally retained.
+        """
+        definition = _canonical(json.loads(definition_json))
+        with self._connect() as connection:
+            connection.execute("BEGIN IMMEDIATE")
+            existing = connection.execute(
+                "SELECT definition_json FROM jobs WHERE job_id = ?", (job_id,)
+            ).fetchone()
+            if existing is not None and existing["definition_json"] != definition:
+                raise JobConflict("reconciliation has a different job definition")
+            connection.execute(
+                "DELETE FROM events WHERE job_id = ? AND sequence > ?",
+                (job_id, last_event_sequence),
+            )
+            connection.execute(
+                """
+                INSERT INTO jobs (job_id, definition_json, state, revision,
+                                  last_event_sequence, committed)
+                VALUES (?, ?, ?, ?, ?, ?)
+                ON CONFLICT(job_id) DO UPDATE SET
+                    state = excluded.state, revision = excluded.revision,
+                    last_event_sequence = excluded.last_event_sequence,
+                    committed = excluded.committed
+                """,
+                (job_id, definition, state, revision, last_event_sequence, int(committed)),
+            )
+            if superseded_command_ids:
+                placeholders = ",".join("?" for _ in superseded_command_ids)
+                rows = connection.execute(
+                    f"SELECT command_id, command_json FROM commands WHERE command_id IN ({placeholders})",
+                    superseded_command_ids,
+                ).fetchall()
+                owned_ids = [
+                    row["command_id"] for row in rows
+                    if _command_job_id(row["command_json"]) == job_id
+                ]
+                if owned_ids:
+                    owned_placeholders = ",".join("?" for _ in owned_ids)
+                    connection.execute(
+                        f"UPDATE commands SET state = 'superseded' WHERE command_id IN ({owned_placeholders})",
+                        owned_ids,
+                    )
+
     def begin_file_operation(
         self,
         operation_id: str,
@@ -557,14 +660,42 @@ class ClientStore:
             ).fetchall()
         return [dict(row) for row in rows]
 
-    def _connect(self) -> sqlite3.Connection:
+    @contextmanager
-        connection = sqlite3.connect(self.database, isolation_level=None, timeout=5)
+    def _connect(self):
-        connection.row_factory = sqlite3.Row
+        """Yield one connection while serializing local SQLite writers.
-        connection.execute("PRAGMA foreign_keys = ON")
+
-        connection.execute("PRAGMA journal_mode = WAL")
+        The longer SQLite timeout also covers a short lock held by a separate
-        connection.execute("PRAGMA synchronous = FULL")
+        maintenance process such as a backup.  The lock is deliberately held
-        connection.execute("PRAGMA busy_timeout = 5000")
+        for the full transaction, including ``BEGIN IMMEDIATE``.
-        return connection
+        """
+        with _DATABASE_LOCK:
+            connection = sqlite3.connect(
+                self.database, isolation_level=None, timeout=30
+            )
+            try:
+                connection.row_factory = sqlite3.Row
+                connection.execute("PRAGMA foreign_keys = ON")
+                connection.execute("PRAGMA journal_mode = WAL")
+                connection.execute("PRAGMA synchronous = FULL")
+                connection.execute("PRAGMA busy_timeout = 30000")
+                # Preserve the original ``with connection`` commit/rollback
+                # behavior used by every store operation.
+                with connection:
+                    yield connection
+            finally:
+                connection.close()
+
+
+def _command_job_id(command_json: str) -> str:
+    """Return the job target from canonical protobuf JSON, if it has one."""
+    command = json.loads(command_json)
+    if "assignJob" in command:
+        return str(command["assignJob"].get("job", {}).get("jobId", ""))
+    if "executeStep" in command:
+        return str(command["executeStep"].get("jobId", ""))
+    if "cancelJob" in command:
+        return str(command["cancelJob"].get("jobId", ""))
+    return ""
 
 
 def _canonical(value: object) -> str:

src/archive_clients/syncthing.py

@@ -139,19 +139,14 @@ class SyncthingTransferObserver:
 
     def status(self) -> SyncthingTransferStatus:
         published = load_published_transfer(self.local_job_directory)
-        total = 0
+        declared_files = [
-        for entry in published.manifest.files:
+            (entry.payload_relative_path, entry.logical_bytes)
-            total += _verified_job_file_size(
+            for entry in published.manifest.files
-                self.local_job_directory,
+        ] + [
-                entry.payload_relative_path,
+            (artifact.payload_relative_path, artifact.logical_bytes)
-                entry.logical_bytes,
+            for artifact in published.manifest.artifacts
-            )
+        ]
-        for artifact in published.manifest.artifacts:
+        total = sum(size for _, size in declared_files)
-            total += _verified_job_file_size(
-                self.local_job_directory,
-                artifact.payload_relative_path,
-                artifact.logical_bytes,
-            )
 
         completion = self.transport.get_json(
             "/rest/db/completion?"
@@ -178,11 +173,44 @@ class SyncthingTransferObserver:
             name for name in needed_names
             if name == self.job_relative_path or name.startswith(prefix)
         }
-        fraction = float(raw_fraction) / 100
+        complete = not relevant
-        complete = fraction == 1 and not relevant
+        if complete:
+            for relative_path, expected_bytes in declared_files:
+                _verified_job_file_size(
+                    self.local_job_directory,
+                    relative_path,
+                    expected_bytes,
+                )
+            completed_bytes = total
+        else:
+            observed_bytes = sum(
+                _received_job_file_bytes(
+                    self.local_job_directory,
+                    relative_path,
+                    expected_bytes,
+                )
+                for relative_path, expected_bytes in declared_files
+            )
+            observed_fraction = observed_bytes / total if total else 1.0
+            # ``/db/completion`` is folder-wide.  It can be near zero when a
+            # route contains a freshly-created item even though the tracked
+            # job's temporary payload has already received many blocks.  For
+            # an incomplete temporary file, its allocated blocks are the only
+            # job-specific signal, so do not cap them with that unrelated
+            # folder aggregate.  Once every declared file is atomically
+            # present, retain the completion value as a conservative guard
+            # until the need queue has caught up.
+            fraction = (
+                observed_fraction
+                if observed_fraction < 1.0
+                else min(1.0, float(raw_fraction) / 100)
+            )
+            completed_bytes = int(total * fraction)
+        if complete:
+            fraction = 1.0
         return SyncthingTransferStatus(
             fraction,
-            total if complete else int(total * fraction),
+            completed_bytes,
             total,
             complete,
             len(relevant),
@@ -356,7 +384,9 @@ class SyncthingRouteManager:
             local_path = self.config.roots.api_to_local(api_path)
         except ConfigError as exc:
             raise RoutePathConflict("route path is outside the sync root") from exc
-        resolved_root = self.config.local_root.resolve(strict=False)
+        resolved_root = self.config.roots.local_root_for_api(api_path).resolve(
+            strict=False
+        )
         try:
             local_path.resolve(strict=False).relative_to(resolved_root)
         except ValueError as exc:
@@ -369,8 +399,8 @@ class SyncthingRouteManager:
             raise RoutePathConflict("new route path contains unrelated data")
         path.mkdir(parents=True, exist_ok=True)
 
-    @staticmethod
     def _validate_folder(
+        self,
         folder: dict[str, Any],
         api_path: str,
         local_device_id: str,
@@ -382,7 +412,15 @@ class SyncthingRouteManager:
             for item in raw_devices
             if isinstance(item, dict) and isinstance(item.get("deviceID"), str)
         } if isinstance(raw_devices, list) else set()
-        if folder.get("path") != api_path:
+        try:
+            configured_api_path = self._normalized_folder_api_path(
+                folder.get("path")
+            )
+        except RoutePathConflict as exc:
+            raise RoutePathConflict(
+                "existing route ID uses a different path"
+            ) from exc
+        if configured_api_path != api_path:
             raise RoutePathConflict("existing route ID uses a different path")
         if folder.get("type") != "sendreceive":
             raise RouteSetupError("existing route folder is not sendreceive")
@@ -391,6 +429,27 @@ class SyncthingRouteManager:
         if folder.get("paused") is True:
             raise RouteSetupError("existing route folder is paused")
 
+    def _normalized_folder_api_path(self, value: Any) -> str:
+        """Normalize Syncthing's absolute and home-relative path spellings."""
+
+        if not isinstance(value, str) or not value:
+            raise RoutePathConflict("existing route folder path is invalid")
+        candidate = PurePosixPath(value)
+        if candidate.parts and candidate.parts[0] == "~":
+            candidate = self.config.api_root.joinpath(*candidate.parts[1:])
+        if not candidate.is_absolute() or any(
+            part in {"", ".", ".."} for part in candidate.parts
+        ):
+            raise RoutePathConflict("existing route folder path is unsafe")
+        normalized = candidate.as_posix()
+        try:
+            self.config.roots.api_to_local(normalized)
+        except ConfigError as exc:
+            raise RoutePathConflict(
+                "existing route folder path is outside the sync root"
+            ) from exc
+        return normalized
+
     def _wait(self, deadline: float) -> None:
         if time.monotonic() >= deadline:
             raise RouteSetupTimeout("route setup timed out")
@@ -441,6 +500,42 @@ def _verified_job_file_size(
     return metadata.st_size
 
 
+def _received_job_file_bytes(
+    job_directory: Path,
+    relative_path: str,
+    expected_bytes: int,
+) -> int:
+    """Return a conservative receive estimate for one job-owned file.
+
+    Syncthing writes incomplete files as ``.syncthing.<name>.tmp`` and may
+    pre-size that sparse temporary to its final logical length. Allocated
+    blocks, rather than ``st_size``, therefore provide the useful progress
+    signal until the final atomic rename occurs.
+    """
+
+    relative = PurePosixPath(relative_path)
+    current = job_directory
+    for component in relative.parts[:-1]:
+        current = current / component
+    final = current / relative.name
+    try:
+        metadata = final.lstat()
+    except FileNotFoundError:
+        metadata = None
+    if metadata is not None:
+        if stat.S_ISREG(metadata.st_mode) and metadata.st_size == expected_bytes:
+            return expected_bytes
+        return 0
+    temporary = current / f".syncthing.{relative.name}.tmp"
+    try:
+        temporary_metadata = temporary.lstat()
+    except FileNotFoundError:
+        return 0
+    if not stat.S_ISREG(temporary_metadata.st_mode):
+        return 0
+    return min(expected_bytes, temporary_metadata.st_blocks * 512)
+
+
 def _needed_names(value: dict[str, Any]) -> set[str]:
     result: set[str] = set()
     for key in ("progress", "queued", "rest"):

src/archive_clients/transfer.py

@@ -456,6 +456,36 @@ def cleanup_transfer(job_directory: Path) -> bool:
     return True
 
 
+def cleanup_partial_transfer(
+    job_directory: Path,
+    *,
+    job_id: str,
+    store: ClientStore,
+) -> None:
+    """Remove copy/reflink temporaries left before a transfer is published.
+
+    A source-stage failure before ``manifest.json``/``ready.json`` exists
+    cannot use :func:`cleanup_transfer`. The file-operation journal is the
+    authoritative list of owned destinations, so derive each temporary path
+    from it rather than recursively removing arbitrary content from a shared
+    Syncthing folder.
+    """
+
+    for row in store.file_operation_rows(job_id):
+        intent = json.loads(str(row["intent_json"]))
+        destination = job_directory / _relative_path(str(intent["destination"]))
+        temporary = _temporary_path(destination, str(row["operation_id"]))
+        try:
+            metadata = temporary.lstat()
+        except FileNotFoundError:
+            continue
+        if not stat.S_ISREG(metadata.st_mode):
+            raise TransferIntegrityError(
+                "job-owned temporary cleanup path is not a regular file"
+            )
+        temporary.unlink()
+
+
 def canonical_message_json(message: object) -> bytes:
     value = json_format.MessageToDict(
         message,

src/archive_control/v1/__init__.py

@@ -1,2 +1,3 @@
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 """Generated archive_control.v1 bindings."""
 

src/archive_control/v1/client_pb2.py

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 # -*- coding: utf-8 -*-
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE

src/archive_control/v1/client_pb2.pyi

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 import datetime
 
 from archive_control.v1 import common_pb2 as _common_pb2

src/archive_control/v1/common_pb2.py

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 # -*- coding: utf-8 -*-
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE

src/archive_control/v1/common_pb2.pyi

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 import datetime
 
 from google.protobuf import timestamp_pb2 as _timestamp_pb2

src/archive_control/v1/control_pb2.pyi

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 import datetime
 
 from archive_control.v1 import common_pb2 as _common_pb2
@@ -108,8 +108,20 @@ class RequestJobSnapshotCommand(_message.Message):
     job_ids: _containers.RepeatedScalarFieldContainer[str]
     def __init__(self, job_ids: _Optional[_Iterable[str]] = ...) -> None: ...
 
+class ReconcileJobCommand(_message.Message):
+    __slots__ = ("authoritative_job", "authoritative_last_event_sequence", "superseded_command_ids", "reason")
+    AUTHORITATIVE_JOB_FIELD_NUMBER: _ClassVar[int]
+    AUTHORITATIVE_LAST_EVENT_SEQUENCE_FIELD_NUMBER: _ClassVar[int]
+    SUPERSEDED_COMMAND_IDS_FIELD_NUMBER: _ClassVar[int]
+    REASON_FIELD_NUMBER: _ClassVar[int]
+    authoritative_job: _job_pb2.JobRecord
+    authoritative_last_event_sequence: int
+    superseded_command_ids: _containers.RepeatedScalarFieldContainer[str]
+    reason: str
+    def __init__(self, authoritative_job: _Optional[_Union[_job_pb2.JobRecord, _Mapping]] = ..., authoritative_last_event_sequence: _Optional[int] = ..., superseded_command_ids: _Optional[_Iterable[str]] = ..., reason: _Optional[str] = ...) -> None: ...
+
 class Command(_message.Message):
-    __slots__ = ("command_id", "created_at", "assign_job", "execute_step", "cancel_job", "ensure_route", "inventory_query", "request_job_snapshot")
+    __slots__ = ("command_id", "created_at", "assign_job", "execute_step", "cancel_job", "ensure_route", "inventory_query", "request_job_snapshot", "reconcile_job")
     COMMAND_ID_FIELD_NUMBER: _ClassVar[int]
     CREATED_AT_FIELD_NUMBER: _ClassVar[int]
     ASSIGN_JOB_FIELD_NUMBER: _ClassVar[int]
@@ -118,6 +130,7 @@ class Command(_message.Message):
     ENSURE_ROUTE_FIELD_NUMBER: _ClassVar[int]
     INVENTORY_QUERY_FIELD_NUMBER: _ClassVar[int]
     REQUEST_JOB_SNAPSHOT_FIELD_NUMBER: _ClassVar[int]
+    RECONCILE_JOB_FIELD_NUMBER: _ClassVar[int]
     command_id: str
     created_at: _timestamp_pb2.Timestamp
     assign_job: AssignJobCommand
@@ -126,7 +139,8 @@ class Command(_message.Message):
     ensure_route: EnsureRouteCommand
     inventory_query: _inventory_pb2.InventoryQuery
     request_job_snapshot: RequestJobSnapshotCommand
-    def __init__(self, command_id: _Optional[str] = ..., created_at: _Optional[_Union[datetime.datetime, _timestamp_pb2.Timestamp, _Mapping]] = ..., assign_job: _Optional[_Union[AssignJobCommand, _Mapping]] = ..., execute_step: _Optional[_Union[ExecuteStepCommand, _Mapping]] = ..., cancel_job: _Optional[_Union[CancelJobCommand, _Mapping]] = ..., ensure_route: _Optional[_Union[EnsureRouteCommand, _Mapping]] = ..., inventory_query: _Optional[_Union[_inventory_pb2.InventoryQuery, _Mapping]] = ..., request_job_snapshot: _Optional[_Union[RequestJobSnapshotCommand, _Mapping]] = ...) -> None: ...
+    reconcile_job: ReconcileJobCommand
+    def __init__(self, command_id: _Optional[str] = ..., created_at: _Optional[_Union[datetime.datetime, _timestamp_pb2.Timestamp, _Mapping]] = ..., assign_job: _Optional[_Union[AssignJobCommand, _Mapping]] = ..., execute_step: _Optional[_Union[ExecuteStepCommand, _Mapping]] = ..., cancel_job: _Optional[_Union[CancelJobCommand, _Mapping]] = ..., ensure_route: _Optional[_Union[EnsureRouteCommand, _Mapping]] = ..., inventory_query: _Optional[_Union[_inventory_pb2.InventoryQuery, _Mapping]] = ..., request_job_snapshot: _Optional[_Union[RequestJobSnapshotCommand, _Mapping]] = ..., reconcile_job: _Optional[_Union[ReconcileJobCommand, _Mapping]] = ...) -> None: ...
 
 class CommandAck(_message.Message):
     __slots__ = ("command_id", "status", "error")
@@ -139,7 +153,7 @@ class CommandAck(_message.Message):
     def __init__(self, command_id: _Optional[str] = ..., status: _Optional[_Union[CommandAckStatus, str]] = ..., error: _Optional[_Union[_common_pb2.Error, _Mapping]] = ...) -> None: ...
 
 class JobEvent(_message.Message):
-    __slots__ = ("event_id", "job_id", "sequence", "job_revision", "type", "state", "committed", "progress", "error", "observed_resource", "observed_placement", "occurred_at")
+    __slots__ = ("event_id", "job_id", "sequence", "job_revision", "type", "state", "committed", "progress", "error", "observed_resource", "observed_placement", "occurred_at", "command_id")
     EVENT_ID_FIELD_NUMBER: _ClassVar[int]
     JOB_ID_FIELD_NUMBER: _ClassVar[int]
     SEQUENCE_FIELD_NUMBER: _ClassVar[int]
@@ -152,6 +166,7 @@ class JobEvent(_message.Message):
     OBSERVED_RESOURCE_FIELD_NUMBER: _ClassVar[int]
     OBSERVED_PLACEMENT_FIELD_NUMBER: _ClassVar[int]
     OCCURRED_AT_FIELD_NUMBER: _ClassVar[int]
+    COMMAND_ID_FIELD_NUMBER: _ClassVar[int]
     event_id: str
     job_id: str
     sequence: int
@@ -164,7 +179,8 @@ class JobEvent(_message.Message):
     observed_resource: _resource_pb2.ResourceStateFingerprint
     observed_placement: _resource_pb2.Placement
     occurred_at: _timestamp_pb2.Timestamp
-    def __init__(self, event_id: _Optional[str] = ..., job_id: _Optional[str] = ..., sequence: _Optional[int] = ..., job_revision: _Optional[int] = ..., type: _Optional[_Union[JobEventType, str]] = ..., state: _Optional[_Union[_job_pb2.JobState, str]] = ..., committed: _Optional[bool] = ..., progress: _Optional[_Union[_job_pb2.JobProgress, _Mapping]] = ..., error: _Optional[_Union[_common_pb2.Error, _Mapping]] = ..., observed_resource: _Optional[_Union[_resource_pb2.ResourceStateFingerprint, _Mapping]] = ..., observed_placement: _Optional[_Union[_resource_pb2.Placement, _Mapping]] = ..., occurred_at: _Optional[_Union[datetime.datetime, _timestamp_pb2.Timestamp, _Mapping]] = ...) -> None: ...
+    command_id: str
+    def __init__(self, event_id: _Optional[str] = ..., job_id: _Optional[str] = ..., sequence: _Optional[int] = ..., job_revision: _Optional[int] = ..., type: _Optional[_Union[JobEventType, str]] = ..., state: _Optional[_Union[_job_pb2.JobState, str]] = ..., committed: _Optional[bool] = ..., progress: _Optional[_Union[_job_pb2.JobProgress, _Mapping]] = ..., error: _Optional[_Union[_common_pb2.Error, _Mapping]] = ..., observed_resource: _Optional[_Union[_resource_pb2.ResourceStateFingerprint, _Mapping]] = ..., observed_placement: _Optional[_Union[_resource_pb2.Placement, _Mapping]] = ..., occurred_at: _Optional[_Union[datetime.datetime, _timestamp_pb2.Timestamp, _Mapping]] = ..., command_id: _Optional[str] = ...) -> None: ...
 
 class JobSnapshot(_message.Message):
     __slots__ = ("job", "last_event_sequence", "in_flight_command_ids")

src/archive_control/v1/envelope_pb2.py

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 # -*- coding: utf-8 -*-
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE

src/archive_control/v1/envelope_pb2.pyi

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 import datetime
 
 from archive_control.v1 import client_pb2 as _client_pb2

src/archive_control/v1/inventory_pb2.py

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 # -*- coding: utf-8 -*-
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE

src/archive_control/v1/inventory_pb2.pyi

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 from archive_control.v1 import common_pb2 as _common_pb2
 from archive_control.v1 import resource_pb2 as _resource_pb2
 from google.protobuf.internal import containers as _containers

src/archive_control/v1/job_pb2.py

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 # -*- coding: utf-8 -*-
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE

src/archive_control/v1/job_pb2.pyi

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 import datetime
 
 from archive_control.v1 import common_pb2 as _common_pb2

src/archive_control/v1/resource_pb2.py

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 # -*- coding: utf-8 -*-
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE

src/archive_control/v1/resource_pb2.pyi

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 import datetime
 
 from google.protobuf import timestamp_pb2 as _timestamp_pb2

src/archive_control/v1/route_pb2.py

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 # -*- coding: utf-8 -*-
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE

src/archive_control/v1/route_pb2.pyi

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 import datetime
 
 from google.protobuf import timestamp_pb2 as _timestamp_pb2

src/archive_control/v1/transfer_pb2.py

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 # -*- coding: utf-8 -*-
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE

src/archive_control/v1/transfer_pb2.pyi

@@ -1,4 +1,4 @@
-# archive-control-proto commit: 4ec852014dad74606d4078b3ae1aa208c814b033
+# archive-control-proto commit: 03b6751d420e8e4e4cc9aeef4f76b13e28a7265f
 import datetime
 
 from archive_control.v1 import resource_pb2 as _resource_pb2

tests/test_config.py

@@ -1,7 +1,7 @@
 import os
 import tempfile
 import unittest
-from pathlib import Path
+from pathlib import Path, PurePosixPath
 from unittest.mock import patch
 
 from archive_clients.config import ClientConfig, ConfigError, RootMapping
@@ -34,6 +34,7 @@ class ConfigTests(unittest.TestCase):
                 root / "qb/a/b",
             )
             self.assertEqual(config.jobs.stall_after, 30 * 60)
+            self.assertEqual(config.jobs.free_space_reserve_bytes, 32 * 1024 * 1024)
             self.assertEqual(
                 config.syncthing.advertised_addresses, ("dynamic",)
             )
@@ -62,6 +63,21 @@ class ConfigTests(unittest.TestCase):
         with self.assertRaises(ConfigError):
             mapping.api_to_local("/elsewhere/file")
 
+    def test_mapping_can_override_one_syncthing_folder_locally(self):
+        mapping = RootMapping(
+            PurePosixPath("/sync"),
+            Path("/local/sync"),
+            ((PurePosixPath("/sync/DownloadsSync"), Path("/local/qb/Sync")),),
+        )
+        self.assertEqual(
+            mapping.api_to_local("/sync/DownloadsSync/job/ready.json"),
+            Path("/local/qb/Sync/job/ready.json"),
+        )
+        self.assertEqual(
+            mapping.local_root_for_api("/sync/DownloadsSync"),
+            Path("/local/qb/Sync"),
+        )
+
     def test_endpoint_scheme_and_job_keys_are_strict(self):
         with tempfile.TemporaryDirectory() as directory:
             root = Path(directory)

tests/test_daemon.py

@@ -22,6 +22,211 @@ from archive_control.v1 import (
 
 
 class DaemonTransportTests(unittest.IsolatedAsyncioTestCase):
+    async def test_unrelated_job_commands_execute_concurrently(self):
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            token = root / "token"
+            token.write_text("shared-secret", encoding="utf-8")
+            os.chmod(token, 0o600)
+            service = ServiceConfig("http://local", PurePosixPath("/api"), root)
+            config = ClientConfig(
+                "cache-1", "Cache 1", "cache", "ws://control", token,
+                root / "state.db", root / "backups", service, service,
+            )
+            probe = FilesystemProbe(root, True, True, True, True, True)
+            daemon = ArchiveClientDaemon(config, [probe, probe], [])
+            started: set[str] = set()
+            release = asyncio.Event()
+
+            async def execute(command, correlation_id, outbound):
+                started.add(command.assign_job.job.job_id)
+                await release.wait()
+
+            daemon._execute_job_command_locked = execute
+            commands = []
+            for _ in range(2):
+                command = control_pb2.Command(command_id=str(uuid4()))
+                command.assign_job.job.job_id = str(uuid4())
+                commands.append(command)
+            outbound = asyncio.Queue()
+            tasks = [
+                asyncio.create_task(
+                    daemon._execute_job_command(command, "", outbound)
+                )
+                for command in commands
+            ]
+            for _ in range(100):
+                if len(started) == 2:
+                    break
+                await asyncio.sleep(0.01)
+            self.assertEqual(len(started), 2)
+            release.set()
+            await asyncio.gather(*tasks)
+
+    async def test_silent_control_connection_ends_for_reconnect(self):
+        """A lost server heartbeat must not leave durable commands stranded."""
+
+        async def control(websocket):
+            registration = decode(await websocket.recv())
+            self.assertEqual(registration.WhichOneof("payload"), "register_request")
+            response = new_envelope()
+            response.correlation_id = registration.message_id
+            response.register_response.status = (
+                client_pb2.REGISTRATION_STATUS_ACCEPTED
+            )
+            response.register_response.negotiated_version.major = 2
+            await websocket.send(encode(response))
+            # Deliberately keep TCP/WebSocket open but send no application
+            # heartbeats. This models a stale proxy/server-side session.
+            await websocket.wait_closed()
+
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            token = root / "token"
+            token.write_text("shared-secret", encoding="utf-8")
+            os.chmod(token, 0o600)
+            async with serve(control, "127.0.0.1", 0, ping_interval=None) as server:
+                port = server.sockets[0].getsockname()[1]
+                service = ServiceConfig(
+                    "http://local", PurePosixPath("/api"), root,
+                )
+                config = ClientConfig(
+                    "cache-1", "Cache 1", "cache",
+                    f"ws://127.0.0.1:{port}", token,
+                    root / "state.db", root / "backups", service, service,
+                    ConnectionConfig(
+                        registration_timeout=1,
+                        offline_timeout=0.05,
+                        reconnect_initial=0.01,
+                        reconnect_max=0.01,
+                        reconnect_jitter=False,
+                    ),
+                )
+                probe = FilesystemProbe(root, True, True, True, True, True)
+                daemon = ArchiveClientDaemon(config, [probe, probe], [])
+                await asyncio.to_thread(daemon.store.initialize)
+                with self.assertRaisesRegex(
+                    RuntimeError, "control heartbeat timed out"
+                ):
+                    await asyncio.wait_for(daemon._connection(), 1)
+
+    async def test_failed_writer_ends_connection_without_waiting_for_heartbeat(self):
+        """A send failure must immediately reach the reconnect supervisor."""
+
+        async def control(websocket):
+            registration = decode(await websocket.recv())
+            response = new_envelope()
+            response.correlation_id = registration.message_id
+            response.register_response.status = (
+                client_pb2.REGISTRATION_STATUS_ACCEPTED
+            )
+            response.register_response.negotiated_version.major = 2
+            await websocket.send(encode(response))
+            await websocket.wait_closed()
+
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            token = root / "token"
+            token.write_text("shared-secret", encoding="utf-8")
+            os.chmod(token, 0o600)
+            async with serve(control, "127.0.0.1", 0, ping_interval=None) as server:
+                port = server.sockets[0].getsockname()[1]
+                service = ServiceConfig("http://local", PurePosixPath("/api"), root)
+                config = ClientConfig(
+                    "cache-1", "Cache 1", "cache",
+                    f"ws://127.0.0.1:{port}", token,
+                    root / "state.db", root / "backups", service, service,
+                )
+                probe = FilesystemProbe(root, True, True, True, True, True)
+                daemon = ArchiveClientDaemon(config, [probe, probe], [])
+                await asyncio.to_thread(daemon.store.initialize)
+
+                async def failed_writer(websocket, outbound):
+                    raise OSError("simulated broken socket")
+
+                daemon._writer = failed_writer
+                with self.assertRaisesRegex(RuntimeError, "writer failed"):
+                    await asyncio.wait_for(daemon._connection(), 1)
+
+    async def test_full_outbound_queue_aborts_connection_instead_of_blocking_heartbeats(self):
+        """Bulk output cannot indefinitely block the receive/heartbeat loop."""
+
+        async def control(websocket):
+            registration = decode(await websocket.recv())
+            response = new_envelope()
+            response.correlation_id = registration.message_id
+            response.register_response.status = (
+                client_pb2.REGISTRATION_STATUS_ACCEPTED
+            )
+            response.register_response.negotiated_version.major = 2
+            await websocket.send(encode(response))
+            for sequence in range(1, 102):
+                heartbeat = new_envelope()
+                heartbeat.heartbeat.sequence = sequence
+                await websocket.send(encode(heartbeat))
+            await websocket.wait_closed()
+
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            token = root / "token"
+            token.write_text("shared-secret", encoding="utf-8")
+            os.chmod(token, 0o600)
+            async with serve(control, "127.0.0.1", 0, ping_interval=None) as server:
+                port = server.sockets[0].getsockname()[1]
+                service = ServiceConfig("http://local", PurePosixPath("/api"), root)
+                config = ClientConfig(
+                    "cache-1", "Cache 1", "cache",
+                    f"ws://127.0.0.1:{port}", token,
+                    root / "state.db", root / "backups", service, service,
+                    ConnectionConfig(outbound_enqueue_timeout=0.01),
+                )
+                probe = FilesystemProbe(root, True, True, True, True, True)
+                daemon = ArchiveClientDaemon(config, [probe, probe], [])
+                await asyncio.to_thread(daemon.store.initialize)
+
+                async def stopped_writer(websocket, outbound):
+                    await asyncio.Event().wait()
+
+                daemon._writer = stopped_writer
+                with self.assertRaisesRegex(RuntimeError, "outbound queue is blocked"):
+                    await asyncio.wait_for(daemon._connection(), 2)
+
+    async def test_reconnect_resume_skips_historical_job_commands(self):
+        """Registration reconciliation, not command replay, recovers job state."""
+
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            token = root / "token"
+            token.write_text("shared-secret", encoding="utf-8")
+            os.chmod(token, 0o600)
+            service = ServiceConfig("http://local", PurePosixPath("/api"), root)
+            config = ClientConfig(
+                "cache-1", "Cache 1", "cache", "ws://control", token,
+                root / "state.db", root / "backups", service, service,
+            )
+            probe = FilesystemProbe(root, True, True, True, True, True)
+            daemon = ArchiveClientDaemon(config, [probe, probe], [])
+            await asyncio.to_thread(daemon.store.initialize)
+            command = control_pb2.Command(command_id=str(uuid4()))
+            command.execute_step.job_id = str(uuid4())
+            command.execute_step.expected_last_event_sequence = 1
+            acknowledgement = control_pb2.CommandAck(
+                command_id=command.command_id,
+                status=control_pb2.COMMAND_ACK_STATUS_ACCEPTED,
+            )
+            await asyncio.to_thread(
+                daemon.store.accept_command,
+                command.command_id,
+                encode_message(command),
+                encode_message(acknowledgement),
+            )
+            daemon.jobs = Mock()
+            outbound = asyncio.Queue()
+            tasks = set()
+            await daemon._resume_commands(outbound, tasks)
+            self.assertEqual(tasks, set())
+            self.assertTrue(outbound.empty())
+
     async def test_eviction_assignment_and_steps_are_admitted(self):
         with tempfile.TemporaryDirectory() as directory:
             root = Path(directory)
@@ -192,6 +397,10 @@ class DaemonTransportTests(unittest.IsolatedAsyncioTestCase):
                 for _ in range(3)
             ]
             self.assertEqual([item.sequence for item in resumed], [1, 2, 3])
+            self.assertEqual(manager.configure.call_count, 2)
+            self.assertEqual(
+                restarted._route_path("route-1"), root / "routes/route-1"
+            )
 
     async def test_slow_inventory_does_not_block_heartbeat(self):
         with tempfile.TemporaryDirectory() as directory:
@@ -276,7 +485,7 @@ class DaemonTransportTests(unittest.IsolatedAsyncioTestCase):
             response = new_envelope()
             response.correlation_id = registration.message_id
             response.register_response.status = client_pb2.REGISTRATION_STATUS_ACCEPTED
-            response.register_response.negotiated_version.major = 1
+            response.register_response.negotiated_version.major = 2
             await websocket.send(encode(response))
             heartbeat = new_envelope()
             heartbeat.heartbeat.sequence = 7

tests/test_deployment_preflight.py

@@ -0,0 +1,83 @@
+import importlib.util
+import sys
+import unittest
+from unittest import mock
+from pathlib import Path
+
+
+_SCRIPT = Path(__file__).parents[1] / "scripts" / "preflight-deployment.py"
+_SPEC = importlib.util.spec_from_file_location("deployment_preflight", _SCRIPT)
+assert _SPEC is not None and _SPEC.loader is not None
+preflight = importlib.util.module_from_spec(_SPEC)
+sys.modules[_SPEC.name] = preflight
+_SPEC.loader.exec_module(preflight)
+
+
+class DeploymentPreflightTests(unittest.TestCase):
+    def test_maps_nested_container_path_to_host_source(self):
+        container = {
+            "Mounts": [
+                {"Type": "bind", "Source": "/srv/data", "Destination": "/data"},
+                {"Type": "bind", "Source": "/srv/sync", "Destination": "/data/Sync"},
+            ]
+        }
+        mapping = preflight.map_path(container, "/data/Sync/routes/route-1")
+        self.assertEqual(mapping.source, Path("/srv/sync/routes/route-1"))
+        self.assertEqual(str(mapping.destination), "/data/Sync")
+
+    def test_rejects_api_and_client_roots_from_different_host_paths(self):
+        with self.assertRaisesRegex(preflight.CheckFailure, "host paths differ"):
+            preflight.require_same_path(
+                "Syncthing api_root/local_root",
+                preflight.Mapping(Path("/srv/syncthing-config/routes"), Path("/var/syncthing")),
+                preflight.Mapping(Path("/srv/sync/routes"), Path("/data/storage")),
+            )
+
+    def test_rejects_unmounted_container_path(self):
+        with self.assertRaisesRegex(preflight.CheckFailure, "not backed"):
+            preflight.map_path({"Mounts": []}, "/missing")
+
+    def test_maps_future_route_through_syncthing_override(self):
+        config = {
+            "api_root": "/var/syncthing",
+            "local_root": "/data/sync",
+            "local_path_overrides": {
+                "/var/syncthing/routes": "/data/qb/.archive-control-routes",
+            },
+        }
+        self.assertEqual(
+            preflight.route_local_path(config),
+            "/data/qb/.archive-control-routes",
+        )
+
+    def test_runs_hardlink_probe_with_qb_and_route_roots(self):
+        completed = __import__("subprocess").CompletedProcess(
+            args=[], returncode=0, stdout="hard-link staging probe passed\n", stderr=""
+        )
+        with mock.patch.object(preflight.subprocess, "run", return_value=completed) as run:
+            preflight.run_hardlink_probe(
+                "client", "/data/qb", "/data/qb/routes", "1001:1001"
+            )
+        args = run.call_args.args[0]
+        self.assertEqual(args[:6], ["docker", "exec", "--user", "1001:1001", "client", "python"])
+        self.assertEqual(args[-2:], ["/data/qb", "/data/qb/routes"])
+
+    def test_hardlink_probe_failure_is_actionable(self):
+        completed = __import__("subprocess").CompletedProcess(
+            args=[], returncode=1, stdout="", stderr="[Errno 18] Invalid cross-device link"
+        )
+        with mock.patch.object(preflight.subprocess, "run", return_value=completed):
+            with self.assertRaisesRegex(preflight.CheckFailure, "hard-link staging probe failed"):
+                preflight.run_hardlink_probe("client", "/data/qb", "/data/qb/routes")
+
+    def test_existing_route_directory_failure_is_actionable(self):
+        completed = __import__("subprocess").CompletedProcess(
+            args=[], returncode=1, stdout='{"missing":[{"folder_id":"route-1"}]}', stderr=""
+        )
+        with mock.patch.object(preflight.subprocess, "run", return_value=completed):
+            with self.assertRaisesRegex(preflight.CheckFailure, "route directory is missing"):
+                preflight.run_existing_route_directory_check("client", "/config.toml")
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_jobs.py

@@ -1,5 +1,6 @@
 import hashlib
 import tempfile
+import threading
 import unittest
 from pathlib import Path
 from unittest.mock import Mock, patch
@@ -11,6 +12,7 @@ from archive_clients.jobs import (
     JobExecutionError,
     _resource_fingerprint,
 )
+from archive_clients.syncthing import RouteSetupError, SyncthingTransferStatus
 from archive_clients.resources import normalize_resource
 from archive_clients.state import ClientStore
 from archive_control.v1 import control_pb2, job_pb2
@@ -31,7 +33,126 @@ class CompleteSyncthing:
         self.posts.append(path)
 
 
+class SlowRescanSyncthing(CompleteSyncthing):
+    def post(self, path):
+        raise RouteSetupError("Syncthing API is unavailable")
+
+
 class ClientJobHappyPathTests(unittest.TestCase):
+    def test_syncthing_api_outage_during_transfer_is_retried(self):
+        """A transient local REST outage must not terminally fail the job."""
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            store = ClientStore(root / "client.db")
+            store.initialize()
+            definition = job_pb2.JobDefinition(
+                job_id=str(uuid4()),
+                transfer={
+                    "source_client_id": "cache-1",
+                    "target_client_id": "archive-1",
+                    "route_id": "route-1",
+                },
+            )
+            observer = Mock()
+            observer.status.side_effect = [
+                RouteSetupError("Syncthing API is unavailable"),
+                SyncthingTransferStatus(1, 42, 42, True, 0),
+            ]
+            executor = ClientJobExecutor(
+                client_id="archive-1",
+                qbittorrent=Mock(),
+                store=store,
+                qb_root=root,
+                qb_api_root=Path("/downloads"),
+                route_path=lambda _: root,
+                syncthing_transport=Mock(),
+                sparse_supported=True,
+                poll_interval=0,
+            )
+            executor._observer = Mock(return_value=observer)
+            progress = Mock()
+
+            executor._wait_for_syncthing(definition, progress)
+
+            self.assertEqual(observer.status.call_count, 2)
+            progress.assert_called_once_with(1, 42, 42, "0 Syncthing items still needed")
+
+    def test_reconnect_replay_never_duplicates_any_transfer_step(self):
+        for step in (
+            job_pb2.JOB_STEP_KIND_SOURCE_STAGE,
+            job_pb2.JOB_STEP_KIND_SYNCTHING_TRANSFER,
+            job_pb2.JOB_STEP_KIND_TARGET_MATERIALIZE,
+            job_pb2.JOB_STEP_KIND_QB_VERIFY,
+            job_pb2.JOB_STEP_KIND_STAGING_CLEANUP,
+        ):
+            with self.subTest(step=step), tempfile.TemporaryDirectory() as directory:
+                root = Path(directory)
+                store = ClientStore(root / "client.db")
+                store.initialize()
+                definition = job_pb2.JobDefinition(
+                    job_id=str(uuid4()),
+                    idempotency_key=str(uuid4()),
+                    operation=job_pb2.JOB_OPERATION_ARCHIVE,
+                    resource_display_name="reconnect fixture",
+                    transfer={
+                        "source_client_id": "cache-1",
+                        "target_client_id": "archive-1",
+                        "route_id": "route-1",
+                    },
+                )
+                definition.resource_id.info_hash_v1_hex = "a" * 40
+                definition.created_at.GetCurrentTime()
+                executor = ClientJobExecutor(
+                    client_id="cache-1",
+                    qbittorrent=Mock(),
+                    store=store,
+                    qb_root=root,
+                    qb_api_root=Path("/downloads"),
+                    route_path=lambda _: root,
+                    syncthing_transport=Mock(),
+                    sparse_supported=True,
+                )
+                executor.assign(control_pb2.AssignJobCommand(
+                    job=definition,
+                    expected_job_revision=1,
+                    expected_last_event_sequence=0,
+                ))
+                entered = threading.Event()
+                release = threading.Event()
+
+                def execute_step(*_args):
+                    entered.set()
+                    release.wait(1)
+                    return None
+
+                executor._execute_step = Mock(side_effect=execute_step)
+                command = control_pb2.ExecuteStepCommand(
+                    job_id=definition.job_id,
+                    expected_job_revision=1,
+                    expected_last_event_sequence=1,
+                    step=step,
+                    attempt=1,
+                )
+                results: list[list[control_pb2.JobEvent]] = []
+                first = threading.Thread(
+                    target=lambda: results.append(executor.execute(command))
+                )
+                second = threading.Thread(
+                    target=lambda: results.append(executor.execute(command))
+                )
+                first.start()
+                self.assertTrue(entered.wait(1))
+                second.start()
+                release.set()
+                first.join(1)
+                second.join(1)
+
+                self.assertFalse(first.is_alive())
+                self.assertFalse(second.is_alive())
+                self.assertEqual(executor._execute_step.call_count, 1)
+                self.assertEqual(len(results), 2)
+                self.assertEqual(results[0][-1].event_id, results[1][-1].event_id)
+
     def test_capacity_guard_fails_before_data_movement(self):
         with tempfile.TemporaryDirectory() as directory:
             root = Path(directory)
@@ -69,14 +190,166 @@ class ClientJobHappyPathTests(unittest.TestCase):
             with self.subTest(operation=operation), tempfile.TemporaryDirectory() as directory:
                 self._run_transfer(Path(directory), operation)
 
-    def _run_transfer(self, root: Path, operation: int):
+    def test_same_filesystem_source_stage_does_not_require_payload_space(self):
+        with tempfile.TemporaryDirectory() as directory:
+            self._run_transfer(
+                Path(directory),
+                job_pb2.JOB_OPERATION_ARCHIVE,
+                source_stage_free_bytes=32 * 1024 * 1024 + 1024,
+                content=b"x" * 4096,
+            )
+
+    def test_mount_boundary_requires_copy_space_even_with_same_device(self):
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            source_root = root / "source"
+            destination_root = root / "destination"
+            source_root.mkdir()
+            destination_root.mkdir()
+            (source_root / "fixture.bin").write_bytes(b"fixture")
+            with patch(
+                "archive_clients.jobs._mount_id",
+                side_effect=("source-mount", "destination-mount"),
+            ):
+                required = ClientJobExecutor._copy_required_bytes(
+                    source_root,
+                    destination_root,
+                    (("fixture.bin", 7),),
+                )
+            self.assertEqual(required, 7)
+
+    def test_source_stage_survives_a_timed_out_syncthing_rescan(self):
+        with tempfile.TemporaryDirectory() as directory:
+            self._run_transfer(
+                Path(directory),
+                job_pb2.JOB_OPERATION_ARCHIVE,
+                syncthing=SlowRescanSyncthing(),
+            )
+
+    def test_target_step_advances_past_replayed_source_completion(self):
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            store = ClientStore(root / "client.db")
+            store.initialize()
+            definition = job_pb2.JobDefinition(
+                job_id=str(uuid4()),
+                idempotency_key=str(uuid4()),
+                operation=job_pb2.JOB_OPERATION_ARCHIVE,
+                resource_display_name="fixture",
+                transfer={
+                    "source_client_id": "cache-1",
+                    "target_client_id": "archive-1",
+                    "route_id": "route-1",
+                },
+            )
+            definition.resource_id.info_hash_v1_hex = "a" * 40
+            definition.created_at.GetCurrentTime()
+            executor = ClientJobExecutor(
+                client_id="archive-1",
+                qbittorrent=Mock(),
+                store=store,
+                qb_root=root,
+                qb_api_root=Path("/downloads"),
+                route_path=lambda _: root,
+                syncthing_transport=Mock(),
+                sparse_supported=True,
+                poll_interval=0,
+            )
+            executor.assign(control_pb2.AssignJobCommand(
+                job=definition,
+                expected_job_revision=1,
+                expected_last_event_sequence=1,
+            ))
+            source_complete = executor._event(
+                definition,
+                sequence=5,
+                revision=4,
+                event_type=control_pb2.JOB_EVENT_TYPE_STEP_SUCCEEDED,
+                state=job_pb2.JOB_STATE_RUNNING,
+                committed=False,
+                step=job_pb2.JOB_STEP_KIND_SOURCE_STAGE,
+                step_state=job_pb2.STEP_STATE_SUCCEEDED,
+            )
+            executor._record(definition, source_complete)
+
+            with patch.object(executor, "_wait_for_syncthing"):
+                events = executor.execute(control_pb2.ExecuteStepCommand(
+                    job_id=definition.job_id,
+                    expected_job_revision=4,
+                    expected_last_event_sequence=5,
+                    step=job_pb2.JOB_STEP_KIND_SYNCTHING_TRANSFER,
+                    attempt=1,
+                ))
+
+            self.assertEqual(events[0].sequence, 6)
+            self.assertEqual(
+                events[0].progress.step,
+                job_pb2.JOB_STEP_KIND_SYNCTHING_TRANSFER,
+            )
+            self.assertEqual(events[-1].sequence, 7)
+            self.assertEqual(
+                events[-1].type,
+                control_pb2.JOB_EVENT_TYPE_STEP_SUCCEEDED,
+            )
+
+    def test_first_partial_progress_is_durable(self):
+        """A sparse transfer must not lose its only initial observation."""
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            store = ClientStore(root / "client.db")
+            store.initialize()
+            definition = job_pb2.JobDefinition(
+                job_id=str(uuid4()),
+                idempotency_key=str(uuid4()),
+                operation=job_pb2.JOB_OPERATION_ARCHIVE,
+                transfer={
+                    "source_client_id": "cache-1",
+                    "target_client_id": "archive-1",
+                    "route_id": "route-1",
+                },
+            )
+            definition.resource_id.info_hash_v1_hex = "a" * 40
+            definition.created_at.GetCurrentTime()
+            executor = ClientJobExecutor(
+                client_id="archive-1", qbittorrent=Mock(), store=store,
+                qb_root=root, qb_api_root=Path("/downloads"),
+                route_path=lambda _: root, syncthing_transport=Mock(),
+                sparse_supported=True, poll_interval=0,
+            )
+            executor.assign(control_pb2.AssignJobCommand(
+                job=definition, expected_job_revision=1,
+                expected_last_event_sequence=0,
+            ))
+
+            def partial_progress(_definition, _step, progress):
+                progress(0.001, 10, 10_000, "still receiving")
+
+            with patch.object(executor, "_execute_step", partial_progress):
+                events = executor.execute(control_pb2.ExecuteStepCommand(
+                    job_id=definition.job_id, expected_job_revision=1,
+                    expected_last_event_sequence=1,
+                    step=job_pb2.JOB_STEP_KIND_SYNCTHING_TRANSFER, attempt=1,
+                ))
+
+            self.assertEqual(len(events), 3)
+            self.assertEqual(events[1].type, control_pb2.JOB_EVENT_TYPE_PROGRESS)
+            self.assertEqual(events[1].progress.bytes_complete, 10)
+
+    def _run_transfer(
+        self,
+        root: Path,
+        operation: int,
+        *,
+        source_stage_free_bytes: int | None = None,
+        content: bytes = b"archive-control-happy-path",
+        syncthing: CompleteSyncthing | None = None,
+    ):
         source_root = root / "source"
         target_root = root / "target"
         route_root = root / "route"
         source_root.mkdir()
         target_root.mkdir()
         route_root.mkdir()
-        content = b"archive-control-happy-path"
         (source_root / "fixture.bin").write_bytes(content)
         info = {
             b"length": len(content),
@@ -137,7 +410,7 @@ class ClientJobHappyPathTests(unittest.TestCase):
         target_qb.get_resource.side_effect = [
             None, None, resource, resource,
         ]
-        syncthing = CompleteSyncthing()
+        syncthing = syncthing or CompleteSyncthing()
         source = ClientJobExecutor(
             client_id=source_id,
             qbittorrent=source_qb,
@@ -163,19 +436,19 @@ class ClientJobHappyPathTests(unittest.TestCase):
 
         source_assigned = source.assign(control_pb2.AssignJobCommand(
             job=definition,
-            expected_job_revision=1,
+            expected_job_revision=0,
             expected_last_event_sequence=0,
         ))
         target_assigned = target.assign(control_pb2.AssignJobCommand(
             job=definition,
-            expected_job_revision=1,
+            expected_job_revision=0,
-            expected_last_event_sequence=1,
+            expected_last_event_sequence=0,
         ))
-        self.assertEqual(source_assigned[0].sequence, 1)
+        self.assertEqual(source_assigned, [])
-        self.assertEqual(target_assigned[0].sequence, 2)
+        self.assertEqual(target_assigned, [])
 
-        cursor_revision = 1
+        cursor_revision = 0
-        cursor_sequence = 2
+        cursor_sequence = 0
         pipeline = (
             (source, job_pb2.JOB_STEP_KIND_SOURCE_STAGE),
             (target, job_pb2.JOB_STEP_KIND_SYNCTHING_TRANSFER),
@@ -185,13 +458,21 @@ class ClientJobHappyPathTests(unittest.TestCase):
         )
         final = None
         for executor, step in pipeline:
-            events = executor.execute(control_pb2.ExecuteStepCommand(
+            command = control_pb2.ExecuteStepCommand(
                 job_id=definition.job_id,
                 expected_job_revision=cursor_revision,
                 expected_last_event_sequence=cursor_sequence,
                 step=step,
                 attempt=1,
-            ))
+            )
+            if executor is source and step == job_pb2.JOB_STEP_KIND_SOURCE_STAGE and source_stage_free_bytes is not None:
+                with patch(
+                    "archive_clients.jobs.shutil.disk_usage",
+                    return_value=Mock(free=source_stage_free_bytes),
+                ):
+                    events = executor.execute(command)
+            else:
+                events = executor.execute(command)
             self.assertEqual(
                 [event.sequence for event in events],
                 list(range(

tests/test_qbittorrent.py

@@ -205,6 +205,54 @@ class QBittorrentReaderTests(unittest.TestCase):
         self.assertEqual(resources, [])
         self.assertEqual(len(opener.calls), 2)
 
+    def test_listing_skips_malformed_torrent_and_keeps_valid_resources(self):
+        def torrent(name, content):
+            info = {
+                b"length": len(content), b"name": name.encode(),
+                b"piece length": 16384, b"pieces": b"x" * 20,
+            }
+            return encode({b"info": info}), hashlib.sha1(encode(info)).hexdigest()
+
+        first_bytes, first_hash = torrent("first.txt", b"one")
+        malformed_bytes, malformed_hash = torrent("broken.txt", b"bad")
+        second_bytes, second_hash = torrent("second.txt", b"two")
+        torrents = [
+            {"hash": first_hash, "name": "first.txt", "state": "uploading"},
+            {"hash": malformed_hash, "name": "broken.txt", "state": "stalledUP"},
+            {"hash": second_hash, "name": "second.txt", "state": "uploading"},
+        ]
+        responses = [
+            b"Ok.", json.dumps(torrents).encode(),
+            b'[{"index":0,"name":"first.txt","size":3,"progress":1,"priority":1}]',
+            first_bytes,
+            b'[{"index":0,"name":"broken.txt","size":3,"progress":1,"priority":1},'
+            b'{"index":1,"name":"unexpected.txt","size":1,"progress":1,"priority":1}]',
+            malformed_bytes,
+            b'[{"index":0,"name":"second.txt","size":3,"progress":1,"priority":1}]',
+            second_bytes,
+        ]
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            password = root / "password"
+            password.write_text("secret", encoding="utf-8")
+            os.chmod(password, 0o600)
+            config = ServiceConfig(
+                "http://qb", PurePosixPath("/downloads"), root,
+                username="admin", password_file=password,
+            )
+            opener = _Opener(responses)
+            with patch(
+                "archive_clients.qbittorrent.request.build_opener",
+                return_value=opener,
+            ), self.assertLogs("archive_clients.qbittorrent", "WARNING") as logs:
+                resources = QBittorrentReader(config).list_resources()
+
+        self.assertEqual(
+            [resource.summary.display_name for resource in resources],
+            ["first.txt", "second.txt"],
+        )
+        self.assertIn(malformed_hash, "\n".join(logs.output))
+
     def test_stopped_add_selection_recheck_and_entry_only_delete(self):
         torrent_hash = "a" * 40
         responses = [

tests/test_resources.py

@@ -118,6 +118,47 @@ class ResourceTests(unittest.TestCase):
         self.assertEqual(root.available_file_count, 1)
         self.assertEqual(root.available_logical_bytes, 3)
 
+    def test_qbittorrent_hidden_padding_files_are_normalized(self):
+        info = {
+            b"files": [
+                {b"length": 3, b"path": [b"first.bin"]},
+                {
+                    b"length": 5,
+                    b"path": [b"_____padding_file_5"],
+                },
+                {b"length": 7, b"path": [b"last.bin"]},
+            ],
+            b"name": b"with-padding",
+            b"piece length": 16384,
+            b"pieces": b"x" * 20,
+        }
+        metainfo = encode({b"info": info})
+        torrent_hash = hashlib.sha1(encode(info)).hexdigest()
+        normalized = normalize_resource(
+            {
+                "hash": torrent_hash,
+                "name": "with-padding",
+                "state": "stalledUP",
+            },
+            [
+                {
+                    "index": 0, "name": "with-padding/first.bin",
+                    "size": 3, "completed": 3, "priority": 1,
+                },
+                {
+                    "index": 1, "name": "with-padding/last.bin",
+                    "size": 7, "completed": 7, "priority": 1,
+                },
+            ],
+            metainfo,
+        )
+        self.assertEqual(
+            [item.canonical_path for item in normalized.files],
+            ["with-padding/first.bin", "with-padding/last.bin"],
+        )
+        self.assertEqual(normalized.summary.total_file_count, 2)
+        self.assertEqual(normalized.summary.selected_complete_bytes, 10)
+
     def test_noncanonical_and_unsafe_paths_are_distinct(self):
         info = {
             b"length": 3,

tests/test_routes.py

@@ -62,6 +62,32 @@ class RouteDiscoveryTests(unittest.TestCase):
         self.assertEqual(routes[0].local_relative_path, "DownloadsSync")
         self.assertEqual(routes[0].state, route_pb2.ROUTE_STATE_DISCOVERED)
 
+    def test_discovery_accepts_a_safe_local_folder_override(self):
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            override = root / "qb/Sync"
+            override.mkdir(parents=True)
+            roots = RootMapping(
+                PurePosixPath("/var/syncthing"),
+                root / "sync",
+                ((PurePosixPath("/var/syncthing/DownloadsSync"), override),),
+            )
+            routes = discover_routes(
+                {"folders": [{
+                    "id": "DownloadsSync",
+                    "path": "~/DownloadsSync",
+                    "type": "sendreceive",
+                    "devices": [
+                        {"deviceID": "LOCAL"},
+                        {"deviceID": "ARCHIVE"},
+                    ],
+                }]},
+                "LOCAL",
+                roots,
+                True,
+            )
+        self.assertEqual([route.route_id for route in routes], ["DownloadsSync"])
+
 
 if __name__ == "__main__":
     unittest.main()

tests/test_state.py

@@ -1,6 +1,7 @@
 import tempfile
 import unittest
 import os
+import threading
 from pathlib import Path
 from uuid import uuid4
 
@@ -13,6 +14,40 @@ from archive_clients.state import (
 
 
 class ClientStoreTests(unittest.TestCase):
+    def test_database_connections_serialize_local_writers(self):
+        """Concurrent jobs share one daemon DB without SQLite lock failures."""
+        with tempfile.TemporaryDirectory() as directory:
+            database = Path(directory) / "state.db"
+            first = ClientStore(database)
+            second = ClientStore(database)
+            first.initialize()
+            barrier = threading.Barrier(2)
+            failures: list[Exception] = []
+
+            def write(store, command_id):
+                try:
+                    barrier.wait()
+                    store.accept_command(command_id, '{"kind":"job"}', '{"ok":true}')
+                except Exception as exc:  # pragma: no cover - assertion below
+                    failures.append(exc)
+
+            left = threading.Thread(target=write, args=(first, "command-1"))
+            right = threading.Thread(target=write, args=(second, "command-2"))
+            left.start()
+            right.start()
+            left.join(1)
+            right.join(1)
+
+            self.assertFalse(left.is_alive())
+            self.assertFalse(right.is_alive())
+            self.assertEqual(failures, [])
+            self.assertEqual(len(first.list_accepted_commands()), 2)
+            with first._connect() as connection:
+                self.assertEqual(
+                    connection.execute("PRAGMA busy_timeout").fetchone()[0],
+                    30000,
+                )
+
     def test_command_acceptance_is_durable_and_content_addressed(self):
         with tempfile.TemporaryDirectory() as directory:
             database = Path(directory) / "state.db"
@@ -142,6 +177,34 @@ class ClientStoreTests(unittest.TestCase):
                     "job-1", "baseline", {"selected": [2]}
                 )
 
+    def test_reconciliation_retires_only_stale_job_leases(self):
+        with tempfile.TemporaryDirectory() as directory:
+            store = ClientStore(Path(directory) / "state.db")
+            store.initialize()
+            stale = store.accept_command(
+                "stale", '{"executeStep":{"jobId":"job-1"}}',
+                '{"status":"COMMAND_ACK_STATUS_ACCEPTED"}',
+            )
+            store.accept_command(
+                "other", '{"executeStep":{"jobId":"job-2"}}',
+                '{"status":"COMMAND_ACK_STATUS_ACCEPTED"}',
+            )
+            self.assertEqual(stale.state, "accepted")
+            store.save_job(
+                "job-1", '{"jobId":"job-1"}', "JOB_STATE_RUNNING", 3, 3, False,
+            )
+            store.reconcile_job(
+                job_id="job-1", definition_json='{"jobId":"job-1"}',
+                state="JOB_STATE_QUEUED", revision=0,
+                last_event_sequence=0, committed=False,
+                superseded_command_ids=["stale"],
+            )
+            self.assertFalse(store.is_command_active("stale"))
+            self.assertTrue(store.is_command_active("other"))
+            row = store.job_snapshot_rows(["job-1"])[0]
+            self.assertEqual(row["last_event_sequence"], 0)
+            self.assertEqual(row["state"], "JOB_STATE_QUEUED")
+
 
 if __name__ == "__main__":
     unittest.main()

tests/test_syncthing.py

@@ -125,6 +125,24 @@ class SyncthingRouteManagerTests(unittest.TestCase):
             self.manager.configure(self.spec, time.monotonic() + 1)
         self.assertEqual(self.transport.puts, [])
 
+    def test_existing_home_relative_folder_path_is_accepted(self):
+        self.transport.config["devices"].append({"deviceID": "PEER"})
+        self.transport.config["folders"].append(
+            {
+                "id": "route-1",
+                "path": "~/routes/route-1",
+                "type": "sendreceive",
+                "devices": [{"deviceID": "LOCAL"}, {"deviceID": "PEER"}],
+            }
+        )
+
+        configured = self.manager.configure(
+            self.spec, time.monotonic() + 1
+        )
+
+        self.assertEqual(self.transport.puts, [])
+        self.assertFalse(configured.local_route.archive_control_created)
+
     def test_bidirectional_nonce_and_ack_are_required(self):
         configured = self.manager.configure(self.spec, time.monotonic() + 1)
         peer_nonce = configured.local_path / (

tests/test_transfer.py

@@ -11,6 +11,7 @@ from archive_clients.transfer import (
     FileMaterializer,
     TransferIntegrityError,
     canonical_message_json,
+    cleanup_partial_transfer,
     load_published_transfer,
     materialize_transfer,
     stage_transfer,
@@ -206,6 +207,33 @@ class TransferHappyPathTests(unittest.TestCase):
             os.stat(copied).st_blocks * 512, os.stat(copied).st_size
         )
 
+    def test_partial_cleanup_removes_only_journalled_temporary(self):
+        job_id = str(uuid4())
+        job_root = self.sync / ".archive-control/jobs" / job_id
+        destination = job_root / "payload/album/one.bin"
+        destination.parent.mkdir(parents=True)
+        operation_id = "interrupted-copy"
+        self.store.begin_file_operation(
+            operation_id,
+            job_id,
+            '{"destination":"payload/album/one.bin"}',
+        )
+        temporary = destination.with_name(
+            ".one.bin.archive-control-"
+            + hashlib.sha256(operation_id.encode()).hexdigest()[:16]
+            + ".tmp"
+        )
+        temporary.write_bytes(b"partial")
+        unrelated = destination.parent / "keep-me"
+        unrelated.write_bytes(b"unrelated")
+
+        cleanup_partial_transfer(
+            job_root, job_id=job_id, store=self.store
+        )
+
+        self.assertFalse(temporary.exists())
+        self.assertTrue(unrelated.is_file())
+
     def test_canonical_manifest_json_is_stable(self):
         manifest = self._manifest()
         first = canonical_message_json(manifest)