Add --platform flag for build/deploy sub-cmd (#1076)

Signed-off-by: Matej Vasek <mvasek@redhat.com>

cmd/build.go

@@ -3,6 +3,7 @@ package cmd
 import (
 	"errors"
 	"fmt"
+	"os"
 
 	"github.com/AlecAivazis/survey/v2"
 	"github.com/AlecAivazis/survey/v2/terminal"
@@ -46,7 +47,7 @@ and the image name is stored in the configuration file.
 {{.Name}} build --builder=pack --builder-image cnbs/sample-builder:bionic
 `,
 		SuggestFor: []string{"biuld", "buidl", "built"},
-		PreRunE:    bindEnv("image", "path", "builder", "registry", "confirm", "push", "builder-image"),
+		PreRunE:    bindEnv("image", "path", "builder", "registry", "confirm", "push", "builder-image", "platform"),
 	}
 
 	cmd.Flags().StringP("builder", "b", "pack", "build strategy to use when creating the underlying image. Currently supported build strategies are 'pack' and 's2i'.")
@@ -55,6 +56,7 @@ and the image name is stored in the configuration file.
 	cmd.Flags().StringP("image", "i", "", "Full image name in the form [registry]/[namespace]/[name]:[tag] (optional). This option takes precedence over --registry (Env: $FUNC_IMAGE)")
 	cmd.Flags().StringP("registry", "r", GetDefaultRegistry(), "Registry + namespace part of the image to build, ex 'quay.io/myuser'.  The full image name is automatically determined based on the local directory name. If not provided the registry will be taken from func.yaml (Env: $FUNC_REGISTRY)")
 	cmd.Flags().BoolP("push", "u", false, "Attempt to push the function image after being successfully built")
+	cmd.Flags().StringP("platform", "", "", "Target platform to build (e.g. linux/amd64).")
 	setPathFlag(cmd)
 
 	if err := cmd.RegisterFlagCompletionFunc("builder", CompleteBuildStrategyList); err != nil {
@@ -158,9 +160,12 @@ func runBuild(cmd *cobra.Command, _ []string, newClient ClientFactory) (err erro
 	// Choose a builder based on the value of the --builder flag
 	var builder fn.Builder
 	if config.Builder == "pack" {
+		if config.Platform != "" {
+			fmt.Fprintln(os.Stderr, "the --platform flag works only with s2i build")
+		}
 		builder = buildpacks.NewBuilder(buildpacks.WithVerbose(config.Verbose))
 	} else if config.Builder == "s2i" {
-		builder = s2i.NewBuilder(s2i.WithVerbose(config.Verbose))
+		builder = s2i.NewBuilder(s2i.WithVerbose(config.Verbose), s2i.WithPlatform(config.Platform))
 	} else {
 		err = errors.New("unrecognized builder: valid values are: s2i, pack")
 		return
@@ -216,6 +221,8 @@ type buildConfig struct {
 	// BuilderImage is the image (name or mapping) to use for building.  Usually
 	// set automatically.
 	BuilderImage string
+
+	Platform string
 }
 
 func newBuildConfig() buildConfig {
@@ -228,6 +235,7 @@ func newBuildConfig() buildConfig {
 		Builder:      viper.GetString("builder"),
 		BuilderImage: viper.GetString("builder-image"),
 		Push:         viper.GetBool("push"),
+		Platform:     viper.GetString("platform"),
 	}
 }
 

cmd/deploy.go

@@ -49,7 +49,7 @@ that is pushed to an image registry, and finally the function's Knative service
 {{.Name}} deploy --image quay.io/myuser/myfunc -n myns
 `,
 		SuggestFor: []string{"delpoy", "deplyo"},
-		PreRunE:    bindEnv("image", "path", "registry", "confirm", "build", "push", "git-url", "git-branch", "git-dir", "builder", "builder-image"),
+		PreRunE:    bindEnv("image", "path", "registry", "confirm", "build", "push", "git-url", "git-branch", "git-dir", "builder", "builder-image", "platform"),
 	}
 
 	cmd.Flags().BoolP("confirm", "c", false, "Prompt to confirm all configuration options (Env: $FUNC_CONFIRM)")
@@ -66,6 +66,7 @@ that is pushed to an image registry, and finally the function's Knative service
 	cmd.Flags().StringP("image", "i", "", "Full image name in the form [registry]/[namespace]/[name]:[tag] (optional). This option takes precedence over --registry (Env: $FUNC_IMAGE)")
 	cmd.Flags().StringP("registry", "r", GetDefaultRegistry(), "Registry + namespace part of the image to build, ex 'quay.io/myuser'.  The full image name is automatically determined based on the local directory name. If not provided the registry will be taken from func.yaml (Env: $FUNC_REGISTRY)")
 	cmd.Flags().BoolP("push", "u", true, "Attempt to push the function image to registry before deploying (Env: $FUNC_PUSH)")
+	cmd.Flags().StringP("platform", "", "", "Target platform to build (e.g. linux/amd64).")
 	setPathFlag(cmd)
 
 	if err := cmd.RegisterFlagCompletionFunc("build", CompleteDeployBuildType); err != nil {
@@ -174,9 +175,12 @@ func runDeploy(cmd *cobra.Command, _ []string, newClient ClientFactory) (err err
 	// Choose a builder based on the value of the --builder flag
 	var builder fn.Builder
 	if config.Builder == "pack" {
+		if config.Platform != "" {
+			fmt.Fprintln(os.Stderr, "the --platform flag works only with s2i build")
+		}
 		builder = buildpacks.NewBuilder(buildpacks.WithVerbose(config.Verbose))
 	} else if config.Builder == "s2i" {
-		builder = s2i.NewBuilder(s2i.WithVerbose(config.Verbose))
+		builder = s2i.NewBuilder(s2i.WithVerbose(config.Verbose), s2i.WithPlatform(config.Platform))
 	} else {
 		err = errors.New("unrecognized builder: valid values are: s2i, pack")
 		return

docker/platform.go

@@ -0,0 +1,71 @@
+package docker
+
+import (
+	"fmt"
+
+	"github.com/containerd/containerd/platforms"
+	"github.com/google/go-containerregistry/pkg/name"
+	v1 "github.com/google/go-containerregistry/pkg/v1"
+	"github.com/google/go-containerregistry/pkg/v1/remote"
+	gcrTypes "github.com/google/go-containerregistry/pkg/v1/types"
+)
+
+// GetPlatformImage returns image reference for specific platform.
+// If the image is not multi-arch it returns ref argument directly (provided platform matches).
+// If the image is multi-arch it returns digest based reference (provided the platform is part of the multi-arch image).
+func GetPlatformImage(ref, platform string) (string, error) {
+
+	plat, err := platforms.Parse(platform)
+	if err != nil {
+		return "", fmt.Errorf("cannot parse platform: %w", err)
+	}
+
+	r, err := name.ParseReference(ref)
+	if err != nil {
+		return "", fmt.Errorf("cannot parse reference: %w", err)
+	}
+
+	desc, err := remote.Get(r)
+	if err != nil {
+		return "", fmt.Errorf("cannot get remote image: %w", err)
+	}
+
+	if desc.MediaType != gcrTypes.OCIImageIndex && desc.MediaType != gcrTypes.DockerManifestList {
+		// it's non-multi-arch image
+		var img v1.Image
+		var cfg *v1.ConfigFile
+		img, err = desc.Image()
+		if err != nil {
+			return "", fmt.Errorf("cannot get image from the descriptor: %w", err)
+		}
+		cfg, err = img.ConfigFile()
+		if err != nil {
+			return "", fmt.Errorf("cannot get config file for the image: %w", err)
+		}
+
+		if plat.OS == cfg.OS &&
+			plat.Architecture == cfg.Architecture {
+			return ref, nil
+		}
+		return "", fmt.Errorf("the %q platform is not supported by the %q image", platform, ref)
+	}
+
+	idx, err := desc.ImageIndex()
+	if err != nil {
+		return "", fmt.Errorf("cannot get image index: %w", err)
+	}
+
+	idxMft, err := idx.IndexManifest()
+	if err != nil {
+		return "", fmt.Errorf("cannot get index manifest: %w", err)
+	}
+
+	for _, manifest := range idxMft.Manifests {
+		if plat.OS == manifest.Platform.OS &&
+			plat.Architecture == manifest.Platform.Architecture {
+			return r.Context().Name() + "@" + manifest.Digest.String(), nil
+		}
+	}
+
+	return "", fmt.Errorf("the %q platform is not supported by the %q image", platform, ref)
+}

docker/platform_test.go

@@ -0,0 +1,127 @@
+package docker_test
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"testing"
+
+	"github.com/google/go-containerregistry/pkg/name"
+	"github.com/google/go-containerregistry/pkg/registry"
+	v1 "github.com/google/go-containerregistry/pkg/v1"
+	"github.com/google/go-containerregistry/pkg/v1/empty"
+	"github.com/google/go-containerregistry/pkg/v1/mutate"
+	"github.com/google/go-containerregistry/pkg/v1/remote"
+	gcrTypes "github.com/google/go-containerregistry/pkg/v1/types"
+
+	"knative.dev/kn-plugin-func/docker"
+)
+
+func TestPlatform(t *testing.T) {
+	testRegistry := startRegistry(t)
+
+	nonMultiArchBuilder := testRegistry + "/default/builder:nonmultiarch"
+	multiArchBuilder := testRegistry + "/default/builder:multiarch"
+
+	// begin push testing builders to registry
+	tag, err := name.NewTag(nonMultiArchBuilder)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var img v1.Image
+	img, err = mutate.ConfigFile(empty.Image, &v1.ConfigFile{
+		Architecture: "ppc64le",
+		OS:           "linux",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = remote.Write(&tag, img)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	tag, err = name.NewTag(multiArchBuilder)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	zeroHash := v1.Hash{
+		Algorithm: "sha256",
+		Hex:       "0000000000000000000000000000000000000000000000000000000000000000",
+	}
+
+	var imgIdx = mutate.AppendManifests(empty.Index, mutate.IndexAddendum{
+		Add: empty.Index,
+		Descriptor: v1.Descriptor{
+			MediaType: gcrTypes.DockerManifestList,
+			Digest:    zeroHash,
+			Platform: &v1.Platform{
+				Architecture: "ppc64le",
+				OS:           "linux",
+			},
+		},
+	})
+
+	err = remote.WriteIndex(tag, imgIdx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// end push testing builders to registry
+
+	_, err = docker.GetPlatformImage(nonMultiArchBuilder, "windows/amd64")
+	if err == nil {
+		t.Error("expected error but got nil")
+	}
+
+	_, err = docker.GetPlatformImage(multiArchBuilder, "windows/amd64")
+	if err == nil {
+		t.Error("expected error but got nil")
+	}
+
+	var ref string
+
+	ref, err = docker.GetPlatformImage(nonMultiArchBuilder, "linux/ppc64le")
+	if err != nil {
+		t.Errorf("unexpeced error: %v", err)
+	}
+	if ref != nonMultiArchBuilder {
+		t.Error("incorrect reference")
+	}
+
+	ref, err = docker.GetPlatformImage(multiArchBuilder, "linux/ppc64le")
+	if err != nil {
+		t.Errorf("unexpeced error: %v", err)
+	}
+	if ref != testRegistry+"/default/builder@sha256:0000000000000000000000000000000000000000000000000000000000000000" {
+		t.Error("incorrect reference")
+	}
+}
+
+func startRegistry(t *testing.T) (addr string) {
+	s := http.Server{
+		Handler: registry.New(registry.Logger(log.New(io.Discard, "", 0))),
+	}
+	t.Cleanup(func() { s.Close() })
+
+	l, err := net.Listen("tcp", "localhost:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	addr = l.Addr().String()
+
+	go func() {
+		err = s.Serve(l)
+		if err != nil && !errors.Is(err, net.ErrClosed) {
+			fmt.Fprintln(os.Stderr, "ERROR: ", err)
+		}
+	}()
+
+	return addr
+}

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/alecthomas/jsonschema v0.0.0-20210526225647-edb03dcab7bc
 	github.com/buildpacks/pack v0.24.0
 	github.com/cloudevents/sdk-go/v2 v2.8.0
+	github.com/containerd/containerd v1.6.0
 	github.com/containers/image/v5 v5.19.1
 	github.com/coreos/go-semver v0.3.0
 	github.com/docker/cli v20.10.12+incompatible

s2i/builder.go

@@ -53,9 +53,10 @@ type DockerClient interface {
 
 // Builder of Functions using the s2i subsystem.
 type Builder struct {
-	verbose bool
-	impl    build.Builder // S2I builder implementation (aka "Strategy")
-	cli     DockerClient
+	verbose  bool
+	impl     build.Builder // S2I builder implementation (aka "Strategy")
+	cli      DockerClient
+	platform string
 }
 
 type Option func(*Builder)
@@ -82,6 +83,12 @@ func WithDockerClient(cli DockerClient) Option {
 	}
 }
 
+func WithPlatform(platform string) Option {
+	return func(b *Builder) {
+		b.platform = platform
+	}
+}
+
 // NewBuilder creates a new instance of a Builder with static defaults.
 func NewBuilder(options ...Option) *Builder {
 	b := &Builder{}
@@ -100,6 +107,13 @@ func (b *Builder) Build(ctx context.Context, f fn.Function) (err error) {
 		return
 	}
 
+	if b.platform != "" {
+		builderImage, err = docker.GetPlatformImage(builderImage, b.platform)
+		if err != nil {
+			return fmt.Errorf("cannot get platform specific image reference: %w", err)
+		}
+	}
+
 	// Build Config
 	cfg := &api.Config{}
 	cfg.Quiet = !b.verbose

vendor/modules.txt

@@ -178,6 +178,7 @@ github.com/cloudevents/sdk-go/v2/types
 # github.com/containerd/cgroups v1.0.3
 github.com/containerd/cgroups/stats/v1
 # github.com/containerd/containerd v1.6.0
+## explicit
 github.com/containerd/containerd/errdefs
 github.com/containerd/containerd/log
 github.com/containerd/containerd/pkg/userns