fix: defer slow Syncthing rescans

deploy/production/lithium/compose.yaml

@@ -2,7 +2,7 @@ name: archive-control-archive
 
 services:
   archive-client:
-    image: sodium/archive-clients:v0.1.6
+    image: sodium/archive-clients:v0.1.7
     user: "1000:1000"
     restart: unless-stopped
     command: ["--config", "/etc/archive-control/client.toml"]

deploy/production/x1/compose.yaml

@@ -2,7 +2,7 @@ name: archive-control-cache
 
 services:
   archive-client:
-    image: sodium/archive-clients:v0.1.6
+    image: sodium/archive-clients:v0.1.7
     user: "1001:1001"
     restart: unless-stopped
     network_mode: host

deploy/production/x2/compose.yaml

@@ -2,7 +2,7 @@ name: archive-control-cache
 
 services:
   archive-client:
-    image: sodium/archive-clients:v0.1.6
+    image: sodium/archive-clients:v0.1.7
     user: "1001:1001"
     restart: unless-stopped
     network_mode: host

docs/deployment-and-usage.md

@@ -218,7 +218,7 @@ cache/archive routes according to policy.
 ```yaml
 services:
   archive-client:
-    image: sodium/archive-clients:v0.1.6
+    image: sodium/archive-clients:v0.1.7
     user: "1001:1001"
     restart: unless-stopped
     command: ["archive-client", "--config", "/etc/archive-control/client.toml"]

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "archive-clients"
-version = "0.1.6"
+version = "0.1.7"
 requires-python = ">=3.11"
 dependencies = ["protobuf==7.35.1", "websockets==16.0"]
 

src/archive_clients/jobs.py

@@ -4,6 +4,7 @@ from __future__ import annotations
 
 import hashlib
 import json
+import logging
 import os
 import shutil
 import stat
@@ -27,7 +28,7 @@ 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,
@@ -53,6 +54,9 @@ class JobCancelled(JobExecutionError):
     pass
 
 
+logger = logging.getLogger(__name__)
+
+
 class ClientJobExecutor:
     def __init__(
         self,
@@ -579,7 +583,17 @@ 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,
@@ -1145,6 +1159,8 @@ 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):

tests/test_jobs.py

@@ -11,6 +11,7 @@ from archive_clients.jobs import (
     JobExecutionError,
     _resource_fingerprint,
 )
+from archive_clients.syncthing import RouteSetupError
 from archive_clients.resources import normalize_resource
 from archive_clients.state import ClientStore
 from archive_control.v1 import control_pb2, job_pb2
@@ -31,6 +32,11 @@ 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_capacity_guard_fails_before_data_movement(self):
         with tempfile.TemporaryDirectory() as directory:
@@ -97,6 +103,14 @@ class ClientJobHappyPathTests(unittest.TestCase):
                 )
             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 _run_transfer(
         self,
         root: Path,
@@ -104,6 +118,7 @@ class ClientJobHappyPathTests(unittest.TestCase):
         *,
         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"
@@ -171,7 +186,7 @@ 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,