fix: ignore already deleted in postgres service delete

[jason-lynch]

Summary

Adds a condition to ignore NotFound errors in PostgresService.Delete, which happens when the service has already been deleted.

Testing

• Create a database with one node on host-2
• Remove the host-2 control plane service and the postgres service for the database with docker service rm <name or id>
• Forcefully remove host-2 with cp-req remove-host --force host-2

Prior to this change, we'd get an error in the last step from trying to scale down a service that no longer exists.

Summary by CodeRabbit

• Bug Fixes
  • Improved handling of service deletion operations to gracefully handle cases where a service has already been removed, reducing unnecessary error reporting and enhancing system stability during cleanup operations.

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[coderabbitai]

📝 Walkthrough

Walkthrough

The PostgresService.Delete method in Docker Swarm orchestration now gracefully handles the case where a service is not found during scale-down operations, treating it as already deleted and returning nil instead of propagating the error.

Changes

Cohort / File(s)	Summary
Docker Swarm Error Handling server/internal/orchestrator/swarm/postgres_service.go	Added logic to detect docker.ErrNotFound from scale-down operation and treat it as a successful deletion, returning nil instead of an error. Other errors remain unaffected.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Poem

🐰 A service not found, oh what a sight,
No need to fret or pick a fight,
Already deleted, the rabbit knows,
Return nil smoothly as the code flows! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: ignoring already-deleted services in the PostgresService.Delete method.
Description check	✅ Passed	The description includes Summary and Testing sections as required by the template, though it omits Changes, Checklist, and Notes for Reviewers sections.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing touches

• 📝 Generate docstrings

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[coderabbitai]

Actionable comments posted: 0

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

server/internal/orchestrator/swarm/postgres_service.go (1)

169-171: Handle ErrNotFound on ServiceRemove to avoid race failures.

A concurrent delete between scale-down and remove can surface an error, which breaks the idempotent delete behavior. Docker's ServiceRemove() returns ErrNotFound when the service is already gone; this should be treated as success, mirroring the existing pattern for ServiceScale (line 162–164).

Suggested patch

-	if err := client.ServiceRemove(ctx, s.ServiceName); err != nil {
-		return fmt.Errorf("failed to remove postgres service: %w", err)
-	}
+	if err := client.ServiceRemove(ctx, s.ServiceName); err != nil {
+		if errors.Is(err, docker.ErrNotFound) {
+			return nil
+		}
+		return fmt.Errorf("failed to remove postgres service: %w", err)
+	}

[rshoemaker]

lgtm