feat: backend service

backend/internal/dockerclient/errors.go

@@ -0,0 +1,36 @@
+package dockerclient
+
+import "errors"
+
+// Sentinel errors returned by the production adapter and consumed by
+// `internal/runtime`. Tests substitute their own implementations of
+// Client and may return these sentinels verbatim or wrap them with
+// extra context via fmt.Errorf("...: %w", ...).
+var (
+	// ErrNetworkMissing is returned by EnsureNetwork when the configured
+	// user-defined Docker network does not exist on the daemon.
+	// `internal/runtime` treats this as a fatal startup error — Galaxy
+	// never creates Docker networks itself.
+	ErrNetworkMissing = errors.New("dockerclient: network missing")
+
+	// ErrImageNotFound is returned by InspectImage / PullImage(never)
+	// when the image is absent locally and the active pull policy
+	// forbids fetching it.
+	ErrImageNotFound = errors.New("dockerclient: image not found")
+
+	// ErrContainerNotFound is returned by InspectContainer / Stop /
+	// Remove when no container with the supplied id or name exists.
+	// `internal/runtime` treats this as an idempotent miss for Stop and
+	// Remove and as a removed-container signal for InspectContainer.
+	ErrContainerNotFound = errors.New("dockerclient: container not found")
+
+	// ErrInvalidPullPolicy is returned by Run / PullImage when the
+	// supplied PullPolicy is not part of the closed vocabulary.
+	ErrInvalidPullPolicy = errors.New("dockerclient: invalid pull policy")
+
+	// ErrImagePullFailed wraps every PullImage failure path returned to
+	// the caller so `internal/runtime` can attribute the failure to the
+	// pull stage rather than to container creation. The unwrap chain
+	// preserves the underlying daemon error for logs and metrics.
+	ErrImagePullFailed = errors.New("dockerclient: image pull failed")
+)