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

internal/agent/updater/compose_test.go

@@ -108,6 +108,24 @@ func TestComposeExecutor(t *testing.T) {
 		assert.Equal(t, pinned, serviceImage(doc, "web"))
 		assert.Contains(t, out.String(), "resolved "+pinned)
 	})
+	t.Run("a pinned ref is written verbatim and not resolved", func(t *testing.T) {
+		t.Cleanup(cleanOverride)
+		for _, ref := range []string{"gitea.shcizo.se/shcizo/slusk:1.3@" + d, "gitea.shcizo.se/shcizo/slusk@" + d} {
+			rec := &recorder{}
+			dist := &fakeDist{digest: "sha256:other"}
+			var out strings.Builder
+			pinnedJob := job
+			pinnedJob.Ref = ref
+			got, err := setup(fakeCompose{rw, []container.Summary{ct}}, dist, rec).Execute(context.Background(), pinnedJob, &out)
+			require.NoError(t, err)
+			assert.Equal(t, ref, got)
+			assert.Empty(t, dist.refs, "no registry lookup")
+			_, doc := readOverride(t, stack)
+			assert.Equal(t, ref, serviceImage(doc, "web"))
+			assert.Contains(t, out.String(), "pinned "+ref)
+			assert.NotContains(t, out.String(), "resolved")
+		}
+	})
 	t.Run("built from source is refused before anything is written", func(t *testing.T) {
 		t.Cleanup(cleanOverride)
 		rec := &recorder{}

internal/agent/updater/resolve.go

@@ -16,7 +16,8 @@ type DistributionClient interface {
 }
 
 // Resolver turns "repo:tag" into "repo:tag@digest" by asking the local
-// daemon, which contacts the registry.
+// daemon, which contacts the registry. A ref that already has a digest is
+// passed through.
 type Resolver struct {
 	cli  DistributionClient
 	auth *RegistryAuth
@@ -27,13 +28,15 @@ func NewResolver(cli DistributionClient, auth *RegistryAuth) *Resolver {
 	return &Resolver{cli: cli, auth: auth}
 }
 
-// Resolve returns ref pinned to the digest its tag currently points at. It
-// fails for a ref without a tag or with a digest already.
+// Resolve returns ref pinned to the digest its tag currently points at. A ref
+// that already has a digest ("repo:tag@digest" or "repo@digest") is returned
+// unchanged without asking the daemon. It fails for a ref with neither tag nor
+// digest.
 func (r *Resolver) Resolve(ctx context.Context, ref string) (string, error) {
 	p := imageref.Parse(ref)
 	switch {
 	case p.Digest != "":
-		return "", fmt.Errorf("image %q already has a digest", ref)
+		return ref, nil
 	case p.Tag == "":
 		return "", fmt.Errorf("image %q has no tag to resolve", ref)
 	}
@@ -46,3 +49,13 @@ func (r *Resolver) Resolve(ctx context.Context, ref string) (string, error) {
 	}
 	return ref + "@" + info.Descriptor.Digest.String(), nil
 }
+
+// resolveNote is the job-output line that says which ref is deployed:
+// "resolved" when pinned came from resolving a tag, "pinned" when ref already
+// carried its digest.
+func resolveNote(ref, pinned string) string {
+	if pinned == ref {
+		return "pinned " + pinned
+	}
+	return "resolved " + pinned
+}

internal/agent/updater/resolve_test.go

@@ -21,14 +21,21 @@ func TestResolver(t *testing.T) {
 		assert.Equal(t, []string{"gitea.shcizo.se/shcizo/slusk:1.4"}, dist.refs)
 		assert.Equal(t, []string{"enc-gitea"}, dist.auths)
 	})
-	t.Run("digest or missing tag is refused without asking the daemon", func(t *testing.T) {
-		for _, ref := range []string{"repo@sha256:x", "repo:1@sha256:x", "repo"} {
+	t.Run("a ref with a digest passes through without asking the daemon", func(t *testing.T) {
+		for _, ref := range []string{"repo@sha256:x", "repo:1@sha256:x", "localhost:5000/repo:1@sha256:x"} {
 			dist := &fakeDist{digest: d}
-			_, err := NewResolver(dist, nil).Resolve(context.Background(), ref)
-			assert.Error(t, err, ref)
+			got, err := NewResolver(dist, nil).Resolve(context.Background(), ref)
+			require.NoError(t, err, ref)
+			assert.Equal(t, ref, got)
 			assert.Empty(t, dist.refs)
 		}
 	})
+	t.Run("a bare ref is refused without asking the daemon", func(t *testing.T) {
+		dist := &fakeDist{digest: d}
+		_, err := NewResolver(dist, nil).Resolve(context.Background(), "repo")
+		assert.ErrorContains(t, err, "has no tag to resolve")
+		assert.Empty(t, dist.refs)
+	})
 	t.Run("daemon error is wrapped", func(t *testing.T) {
 		cause := errors.New("unauthorized")
 		_, err := NewResolver(&fakeDist{err: cause}, nil).Resolve(context.Background(), "repo:1")

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

internal/agent/updater/swarm_test.go

@@ -77,6 +77,22 @@ func swarmSvc(name string) swarm.Service {
 	}
 }
 
+func TestSwarmUsesPinnedRef(t *testing.T) {
+	const ref = "gitea/gitea:1.26@sha256:abababababababababababababababababababababababababababababababab"
+	job := protocol.JobStart{Kind: protocol.KindSwarm, SwarmClusterID: "c1", SwarmService: "gitea_gitea", Ref: ref}
+	fake := &fakeSwarm{info: managerOf("c1"), svc: swarmSvc("gitea_gitea")}
+	dist := &fakeDist{digest: "sha256:other"}
+	var out bytes.Buffer
+
+	got, err := NewSwarmExecutor(fake, NewResolver(dist, nil), nil).Execute(context.Background(), job, &out)
+
+	require.NoError(t, err)
+	assert.Equal(t, ref, got)
+	assert.Equal(t, ref, fake.updSpec.TaskTemplate.ContainerSpec.Image)
+	assert.Empty(t, dist.refs, "no registry lookup")
+	assert.Contains(t, out.String(), "pinned "+ref)
+}
+
 func TestSwarmExecutor(t *testing.T) {
 	job := protocol.JobStart{Kind: protocol.KindSwarm, SwarmClusterID: "c1", SwarmService: "gitea_gitea", Ref: "gitea/gitea:1.27"}
 	workerInfo := managerOf("c1")