feat(master,agent): deploy digest-pinned refs and route them to protocol 3 agents (#9)

internal/agent/updater/swarm.go

@@ -35,7 +35,7 @@ func NewSwarmExecutor(cli SwarmClient, resolve *Resolver, auth *RegistryAuth) *S
 }
 
 // Execute checks that the local daemon is a manager of the job's cluster,
-// pins job.Ref to its current digest and updates the service to it. The
+// pins job.Ref to its current digest (a ref that has one is used as is) and updates the service to it. The
 // update is addressed by the ID and version of the service that was
 // inspected, so it changes exactly that object. Success means the daemon
 // accepted the new spec, not that the tasks have converged. It returns the
@@ -71,7 +71,7 @@ func (e *SwarmExecutor) Execute(ctx context.Context, job protocol.JobStart, out
 	if err != nil {
 		return "", err
 	}
-	fmt.Fprintf(out, "resolved %s\n", pinned)
+	fmt.Fprintln(out, resolveNote(job.Ref, pinned))
 
 	spec := svc.Spec
 	spec.TaskTemplate.ContainerSpec.Image = pinned