Add generate command

This change adds the generate command to s2i, where it allows
the user to produce a Dockerfile able to be used by any build
system supporting the format, such as buildah and possibly
others.

contrib/completions/bash/s2i

@@ -388,6 +388,41 @@ _s2i_create()
     noun_aliases=()
 }
 
+_s2i_generate()
+{
+    last_command="s2i_generate"
+    commands=()
+
+    flags=()
+    two_word_flags=()
+    local_nonpersistent_flags=()
+    flags_with_completion=()
+    flags_completion=()
+
+    flags+=("--assemble-runtime-user=")
+    local_nonpersistent_flags+=("--assemble-runtime-user=")
+    flags+=("--assemble-user=")
+    local_nonpersistent_flags+=("--assemble-user=")
+    flags+=("--env=")
+    two_word_flags+=("-e")
+    local_nonpersistent_flags+=("--env=")
+    flags+=("--quiet")
+    flags+=("-q")
+    local_nonpersistent_flags+=("--quiet")
+    flags+=("--ca=")
+    flags+=("--cert=")
+    flags+=("--key=")
+    flags+=("--loglevel=")
+    flags+=("--tls")
+    flags+=("--tlsverify")
+    flags+=("--url=")
+    two_word_flags+=("-U")
+
+    must_have_one_flag=()
+    must_have_one_noun=()
+    noun_aliases=()
+}
+
 _s2i_rebuild()
 {
     last_command="s2i_rebuild"
@@ -519,6 +554,7 @@ _s2i()
     commands+=("build")
     commands+=("completion")
     commands+=("create")
+    commands+=("generate")
     commands+=("rebuild")
     commands+=("usage")
     commands+=("version")

contrib/completions/zsh/s2i

@@ -549,6 +549,41 @@ _s2i_create()
     noun_aliases=()
 }
 
+_s2i_generate()
+{
+    last_command="s2i_generate"
+    commands=()
+
+    flags=()
+    two_word_flags=()
+    local_nonpersistent_flags=()
+    flags_with_completion=()
+    flags_completion=()
+
+    flags+=("--assemble-runtime-user=")
+    local_nonpersistent_flags+=("--assemble-runtime-user=")
+    flags+=("--assemble-user=")
+    local_nonpersistent_flags+=("--assemble-user=")
+    flags+=("--env=")
+    two_word_flags+=("-e")
+    local_nonpersistent_flags+=("--env=")
+    flags+=("--quiet")
+    flags+=("-q")
+    local_nonpersistent_flags+=("--quiet")
+    flags+=("--ca=")
+    flags+=("--cert=")
+    flags+=("--key=")
+    flags+=("--loglevel=")
+    flags+=("--tls")
+    flags+=("--tlsverify")
+    flags+=("--url=")
+    two_word_flags+=("-U")
+
+    must_have_one_flag=()
+    must_have_one_noun=()
+    noun_aliases=()
+}
+
 _s2i_rebuild()
 {
     last_command="s2i_rebuild"
@@ -680,6 +715,7 @@ _s2i()
     commands+=("build")
     commands+=("completion")
     commands+=("create")
+    commands+=("generate")
     commands+=("rebuild")
     commands+=("usage")
     commands+=("version")

pkg/build/strategies/dockerfile/dockerfile.go

@@ -168,6 +168,15 @@ func (builder *Dockerfile) CreateDockerfile(config *api.Config) error {
 	for k, v := range config.Labels {
 		imageLabels[k] = v
 	}
+
+	if len(config.ScriptsURL) > 0 {
+		imageLabels[constants.ScriptsURLLabel] = config.ScriptsURL
+	}
+
+	if len(config.Destination) > 0 {
+		imageLabels[constants.DestinationLabel] = config.Destination
+	}
+
 	if len(imageLabels) > 0 {
 		first := true
 		buffer.WriteString("LABEL ")

pkg/cmd/cli/cli.go

@@ -43,6 +43,7 @@ func NewCmdCLI() *cobra.Command {
 	s2iCmd.AddCommand(cmd.NewCmdRebuild(cfg))
 	s2iCmd.AddCommand(cmd.NewCmdUsage(cfg))
 	s2iCmd.AddCommand(cmd.NewCmdCreate())
+	s2iCmd.AddCommand(cmd.NewCmdGenerate(cfg))
 	cmdutil.SetupLogger(s2iCmd.PersistentFlags())
 	basename := filepath.Base(os.Args[0])
 	// Make case-insensitive and strip executable suffix if present

pkg/cmd/cli/cmd/generate.go

@@ -0,0 +1,99 @@
+package cmd
+
+import (
+	"context"
+
+	"github.com/containers/image/v5/transports/alltransports"
+	"github.com/containers/image/v5/types"
+	"github.com/spf13/cobra"
+
+	"github.com/openshift/source-to-image/pkg/api"
+	"github.com/openshift/source-to-image/pkg/api/constants"
+	"github.com/openshift/source-to-image/pkg/build/strategies/dockerfile"
+	"github.com/openshift/source-to-image/pkg/util/fs"
+)
+
+// getImageLabels attempts to inspect an image existing in a remote registry.
+func getImageLabels(ctx context.Context, imageName string) (map[string]string, error) {
+	ref, err := alltransports.ParseImageName(imageName)
+	if err != nil {
+		return nil, err
+	}
+
+	img, err := ref.NewImage(ctx, &types.SystemContext{})
+	if err != nil {
+		return nil, err
+	}
+
+	imageMetadata, err := img.Inspect(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	return imageMetadata.Labels, nil
+}
+
+// generateDockerfile generates a Dockerfile with the given configuration.
+func generateDockerfile(cfg *api.Config) error {
+	fileSystem := fs.NewFileSystem()
+	builder, err := dockerfile.New(cfg, fileSystem)
+	if err != nil {
+		return err
+	}
+
+	_, err = builder.Build(cfg)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// adjustConfigWithImageLabels adjusts the configuration with given labels.
+func adjustConfigWithImageLabels(cfg *api.Config, labels map[string]string) {
+	if v, ok := labels[constants.ScriptsURLLabel]; ok {
+		cfg.ScriptsURL = v
+	}
+
+	if v, ok := labels[constants.DestinationLabel]; ok {
+		cfg.Destination = v
+	}
+
+}
+
+// NewCmdGenerate implements the S2I cli generate command.
+func NewCmdGenerate(cfg *api.Config) *cobra.Command {
+	generateCmd := &cobra.Command{
+		Use:   "generate <image> <dockerfile>",
+		Short: "Generate a Dockerfile based on the provided builder image",
+		Example: `
+# Generate a Dockerfile from a builder image:
+$ s2i generate docker://quay.io/redhat-developer/app-binding-operator Dockerfile.gen
+`,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			if cmd.Flags().NArg() != 2 {
+				return cmd.Help()
+			}
+
+			cfg.BuilderImage = cmd.Flags().Arg(0)
+			cfg.AsDockerfile = cmd.Flags().Arg(1)
+
+			ctx := context.Background()
+			var imageLabels map[string]string
+			var err error
+			if imageLabels, err = getImageLabels(ctx, cfg.BuilderImage); err != nil {
+				return err
+			}
+
+			adjustConfigWithImageLabels(cfg, imageLabels)
+			return generateDockerfile(cfg)
+		},
+	}
+
+	generateCmd.Flags().BoolVarP(&(cfg.Quiet), "quiet", "q", false, "Operate quietly. Suppress all non-error output.")
+	generateCmd.Flags().VarP(&(cfg.Environment), "env", "e", "Specify an single environment variable in NAME=VALUE format")
+	generateCmd.Flags().StringVarP(&(cfg.AssembleUser), "assemble-user", "", "", "Specify the user to run assemble with")
+	generateCmd.Flags().StringVarP(&(cfg.AssembleRuntimeUser), "assemble-runtime-user", "", "", "Specify the user to run assemble-runtime with")
+
+	return generateCmd
+}

test/integration/docker/integration_test.go

@@ -151,7 +151,7 @@ func (i integrationTest) InspectImage(name string) (*dockertypes.ImageInspect, e
 	defer cancel()
 	resp, _, err := engineClient.ImageInspectWithRaw(ctx, name)
 	if err != nil {
-		if dockerapi.IsErrImageNotFound(err) {
+		if dockerapi.IsErrNotFound(err) {
 			return nil, fmt.Errorf("no such image :%q", name)
 		}
 		return nil, err

test/integration/dockerfile/dockerfile_test.go

@@ -154,9 +154,9 @@ func TestDockerfileBuildLabels(t *testing.T) {
 		AssembleUser: "",
 		ImageWorkDir: "",
 		Source:       git.MustParse("https://github.com/sclorg/nodejs-ex"),
-		ScriptsURL:   "",
+		ScriptsURL:   "image:///scripts",
 		Injections:   api.VolumeList{},
-		Destination:  "",
+		Destination:  "/destination",
 
 		Environment: api.EnvironmentList{},
 		Labels: map[string]string{"label1": "value1",
@@ -166,6 +166,8 @@ func TestDockerfileBuildLabels(t *testing.T) {
 		AsDockerfile: filepath.Join(tempdir, "Dockerfile"),
 	}
 	expected := []string{
+		"\"io.openshift.s2i.scripts-url\"=\"image:///scripts\"",
+		"\"io.openshift.s2i.destination\"=\"/destination\"",
 		"\"io.openshift.s2i.build.commit.date\"",
 		"\"io.openshift.s2i.build.commit.id\"",
 		"\"io.openshift.s2i.build.commit.ref\"",