test: cover daemon telemetry publication

cmd/rvbox-server/main.go

@@ -245,15 +245,7 @@ func publishServerTelemetry(ctx context.Context, persistence *store.Store, healt
 	ticker := time.NewTicker(10 * time.Second)
 	defer ticker.Stop()
 	for {
-		sampleContext, cancel := context.WithTimeout(ctx, time.Second)
-		telemetry, err := persistence.Telemetry(sampleContext)
-		cancel()
-		if err != nil {
-			health.Inc("telemetry_read_failure")
-		} else {
-			health.SetGauge("queue_depth", float64(telemetry.QueuedCommands))
-			health.SetGauge("server_charged_bytes", float64(telemetry.ChargedBytes))
-		}
+		publishServerTelemetrySample(ctx, persistence.Telemetry, health)
 		select {
 		case <-ctx.Done():
 			return
@@ -261,3 +253,18 @@ func publishServerTelemetry(ctx context.Context, persistence *store.Store, healt
 		}
 	}
 }
+
+// publishServerTelemetrySample performs one intentionally bounded, best-effort
+// telemetry read. A failed metrics read must never affect server readiness or
+// durable command processing.
+func publishServerTelemetrySample(ctx context.Context, read func(context.Context) (store.Telemetry, error), health *observability.Health) {
+	sampleContext, cancel := context.WithTimeout(ctx, time.Second)
+	telemetry, err := read(sampleContext)
+	cancel()
+	if err != nil {
+		health.Inc("telemetry_read_failure")
+		return
+	}
+	health.SetGauge("queue_depth", float64(telemetry.QueuedCommands))
+	health.SetGauge("server_charged_bytes", float64(telemetry.ChargedBytes))
+}

cmd/rvbox-server/main_test.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/rvbox/rvbox/internal/observability"
+	"github.com/rvbox/rvbox/internal/server/store"
+)
+
+func TestPublishServerTelemetrySample_HP_OPS_07(t *testing.T) {
+	t.Parallel()
+	health := observability.New()
+	publishServerTelemetrySample(context.Background(), func(context.Context) (store.Telemetry, error) {
+		return store.Telemetry{QueuedCommands: 3, ChargedBytes: 4096}, nil
+	}, health)
+	snapshot := health.MetricsSnapshot()
+	if snapshot.Gauges["queue_depth"] != 3 || snapshot.Gauges["server_charged_bytes"] != 4096 {
+		t.Fatalf("server telemetry gauges = %#v", snapshot.Gauges)
+	}
+}
+
+func TestPublishServerTelemetrySampleFailure_BH_OPS_04(t *testing.T) {
+	t.Parallel()
+	health := observability.New()
+	publishServerTelemetrySample(context.Background(), func(context.Context) (store.Telemetry, error) {
+		return store.Telemetry{}, errors.New("store unavailable")
+	}, health)
+	_, _, counters := health.Snapshot()
+	if counters["telemetry_read_failure"] != 1 {
+		t.Fatalf("telemetry failure counters = %#v", counters)
+	}
+}