options to split image steps and manifest steps

Signed-off-by: Avi Deitcher <avi@deitcher.net>

src/cmd/linuxkit/pkg_push.go

@@ -22,6 +22,9 @@ func pkgPush(args []string) {
 	force := flags.Bool("force", false, "Force rebuild")
 	release := flags.String("release", "", "Release the given version")
 	nobuild := flags.Bool("nobuild", false, "Skip the build")
+	manifest := flags.Bool("manifest", true, "Create and push multi-arch manifest")
+	image := flags.Bool("image", true, "Build and push image for the current platform")
+	sign := flags.Bool("sign", true, "sign the manifest, if a manifest is created; ignored if --manifest=false")
 
 	p, err := pkglib.NewFromCLI(flags, args...)
 	if err != nil {
@@ -44,6 +47,16 @@ func pkgPush(args []string) {
 	if *release != "" {
 		opts = append(opts, pkglib.WithRelease(*release))
 	}
+	if *manifest {
+		opts = append(opts, pkglib.WithBuildManifest())
+	}
+	if *image {
+		opts = append(opts, pkglib.WithBuildImage())
+	}
+	// only sign manifests; ignore for image only
+	if *sign && *manifest {
+		opts = append(opts, pkglib.WithBuildSign())
+	}
 
 	if *nobuild {
 		fmt.Printf("Pushing %q without building\n", p.Tag())

src/cmd/linuxkit/pkglib/build.go

@@ -18,6 +18,9 @@ type buildOpts struct {
 	force     bool
 	push      bool
 	release   string
+	manifest  bool
+	sign      bool
+	image     bool
 }
 
 // BuildOpt allows callers to specify options to Build
@@ -47,6 +50,30 @@ func WithBuildPush() BuildOpt {
 	}
 }
 
+// WithBuildImage builds the image
+func WithBuildImage() BuildOpt {
+	return func(bo *buildOpts) error {
+		bo.image = true
+		return nil
+	}
+}
+
+// WithBuildManifest creates a multi-arch manifest for the image
+func WithBuildManifest() BuildOpt {
+	return func(bo *buildOpts) error {
+		bo.manifest = true
+		return nil
+	}
+}
+
+// WithBuildSign signs the image and/or the index
+func WithBuildSign() BuildOpt {
+	return func(bo *buildOpts) error {
+		bo.sign = true
+		return nil
+	}
+}
+
 // WithRelease releases as the given version after push
 func WithRelease(r string) BuildOpt {
 	return func(bo *buildOpts) error {
@@ -64,7 +91,7 @@ func (p Pkg) Build(bos ...BuildOpt) error {
 		}
 	}
 
-	if _, ok := os.LookupEnv("DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE"); !ok && p.trust && bo.push {
+	if _, ok := os.LookupEnv("DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE"); !ok && bo.sign && p.trust && bo.push {
 		return fmt.Errorf("Pushing with trust enabled requires $DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE to be set")
 	}
 
@@ -98,7 +125,7 @@ func (p Pkg) Build(bos ...BuildOpt) error {
 		return fmt.Errorf("Cannot release %q if not pushing", bo.release)
 	}
 
-	d := newDockerRunner(p.trust, p.cache)
+	d := newDockerRunner(p.trust, p.cache, bo.sign)
 
 	if !bo.force {
 		ok, err := d.pull(p.Tag())
@@ -111,7 +138,7 @@ func (p Pkg) Build(bos ...BuildOpt) error {
 		fmt.Println("No image pulled, continuing with build")
 	}
 
-	if !bo.skipBuild {
+	if bo.image && !bo.skipBuild {
 		var args []string
 
 		if err := p.dockerDepends.Do(d); err != nil {
@@ -171,7 +198,7 @@ func (p Pkg) Build(bos ...BuildOpt) error {
 	// matters given we do either pull or build above in the
 	// !force case.
 
-	if err := d.pushWithManifest(p.Tag(), suffix); err != nil {
+	if err := d.pushWithManifest(p.Tag(), suffix, bo.image, bo.manifest, bo.sign); err != nil {
 		return err
 	}
 
@@ -189,7 +216,7 @@ func (p Pkg) Build(bos ...BuildOpt) error {
 		return err
 	}
 
-	if err := d.pushWithManifest(relTag, suffix); err != nil {
+	if err := d.pushWithManifest(relTag, suffix, bo.image, bo.manifest, bo.sign); err != nil {
 		return err
 	}
 

src/cmd/linuxkit/pkglib/docker.go

@@ -39,6 +39,7 @@ var platforms = []string{
 type dockerRunner struct {
 	dct   bool
 	cache bool
+	sign  bool
 
 	// Optional build context to use
 	ctx buildContext
@@ -49,8 +50,8 @@ type buildContext interface {
 	Copy(io.WriteCloser) error
 }
 
-func newDockerRunner(dct, cache bool) dockerRunner {
-	return dockerRunner{dct: dct, cache: cache}
+func newDockerRunner(dct, cache, sign bool) dockerRunner {
+	return dockerRunner{dct: dct, cache: cache, sign: sign}
 }
 
 func isExecErrNotFound(err error) bool {
@@ -83,7 +84,10 @@ func (dr dockerRunner) command(args ...string) error {
 	cmd.Env = os.Environ()
 
 	dct := ""
-	if dr.dct {
+
+	// when we are doing a push, we need to disable DCT if not signing
+	isPush := len(args) >= 2 && args[0] == "image" && args[1] == "push"
+	if dr.dct && (!isPush || dr.sign) {
 		cmd.Env = append(cmd.Env, dctEnableEnv)
 		dct = dctEnableEnv + " "
 	}
@@ -147,10 +151,19 @@ func (dr dockerRunner) push(img string) error {
 	return dr.command("image", "push", img)
 }
 
-func (dr dockerRunner) pushWithManifest(img, suffix string) error {
-	fmt.Printf("Pushing %s\n", img+suffix)
-	if err := dr.push(img + suffix); err != nil {
-		return err
+func (dr dockerRunner) pushWithManifest(img, suffix string, pushImage, pushManifest, sign bool) error {
+	var (
+		digest string
+		l      int
+		err    error
+	)
+	if pushImage {
+		fmt.Printf("Pushing %s\n", img+suffix)
+		if err := dr.push(img + suffix); err != nil {
+			return err
+		}
+	} else {
+		fmt.Print("Image push disabled, skipping...\n")
 	}
 
 	auth, err := getDockerAuth()
@@ -158,16 +171,24 @@ func (dr dockerRunner) pushWithManifest(img, suffix string) error {
 		return fmt.Errorf("failed to get auth: %v", err)
 	}
 
-	fmt.Printf("Pushing %s to manifest %s\n", img+suffix, img)
-	digest, l, err := manifestPush(img, auth)
-	if err != nil {
-		return err
+	if pushManifest {
+		fmt.Printf("Pushing %s to manifest %s\n", img+suffix, img)
+		digest, l, err = manifestPush(img, auth)
+		if err != nil {
+			return err
+		}
+	} else {
+		fmt.Print("Manifest push disabled, skipping...\n")
 	}
 	// if trust is not enabled, nothing more to do
 	if !dr.dct {
 		fmt.Println("trust disabled, not signing")
 		return nil
 	}
+	if !sign {
+		fmt.Println("signing disabled, not signing")
+		return nil
+	}
 	fmt.Printf("Signing manifest for %s\n", img)
 	return signManifest(img, digest, l, auth)
 }
@@ -279,7 +300,7 @@ func signManifest(img, digest string, length int, auth dockertypes.AuthConfig) e
 	}
 
 	// report output
-	fmt.Printf("New signed multi-arch image: %s:%s\n", repo, tag)
+	fmt.Printf("Signed manifest index: %s:%s\n", repo, tag)
 
 	return nil
 }