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

internal/agent/updater/compose.go

@@ -91,7 +91,7 @@ func NewComposeExecutor(cli ComposeDocker, resolve *Resolver, selfID string, run
 	return &ComposeExecutor{cli: cli, resolve: resolve, selfID: selfID, run: run, build: NewBuildChecker(cli, selfID, runOut)}
 }
 
-// Execute pins job.Ref to its current digest, writes it to the stack's
+// Execute pins job.Ref to its current digest (a ref that has one is used as is), writes it to the stack's
 // override file and recreates the service. Working directory and config
 // files come from the service's container labels on this machine, never from
 // the job. It returns the pinned ref.
@@ -150,7 +150,7 @@ func (e *ComposeExecutor) Execute(ctx context.Context, job protocol.JobStart, ou
 	if err != nil {
 		return "", err
 	}
-	fmt.Fprintf(out, "resolved %s\n", pinned)
+	fmt.Fprintln(out, resolveNote(job.Ref, pinned))
 
 	if _, err := WriteOverride(dir, service, pinned); err != nil {
 		return "", err