build: add support for --push

Signed-off-by: danishprakash <danish.prakash@suse.com>

define/build.go

@@ -163,6 +163,7 @@ type BuildOptions struct {
 	// It allows end user to export recently built rootfs into a directory or tar.
 	// See the documentation of 'buildah build --output' for the details of the format.
 	BuildOutput string
+	Push        bool
 	// Additional tags to add to the image that we write, if we know of a
 	// way to add them.
 	AdditionalTags []string

define/types.go

@@ -101,6 +101,8 @@ type Secret struct {
 
 // BuildOutputOptions contains the the outcome of parsing the value of a build --output flag
 type BuildOutputOption struct {
+	Type     string
+	Attrs    map[string]string
 	Path     string // Only valid if !IsStdout
 	IsDir    bool
 	IsStdout bool

imagebuildah/executor.go

@@ -73,6 +73,7 @@ type Executor struct {
 	registry                       string
 	ignoreUnrecognizedInstructions bool
 	quiet                          bool
+	push                           bool
 	runtime                        string
 	runtimeArgs                    []string
 	transientMounts                []Mount
@@ -237,6 +238,7 @@ func newExecutor(logger *logrus.Logger, logPrefix string, store storage.Store, o
 		registry:                       options.Registry,
 		ignoreUnrecognizedInstructions: options.IgnoreUnrecognizedInstructions,
 		quiet:                          options.Quiet,
+		push:                           options.Push, // TODO: not needed if planning to update buildOutput in cli/build
 		runtime:                        options.Runtime,
 		runtimeArgs:                    options.RuntimeArgs,
 		transientMounts:                transientMounts,

imagebuildah/stage_executor.go

@@ -1019,7 +1019,7 @@ func (s *StageExecutor) Execute(ctx context.Context, base string) (imgID string,
 	canGenerateBuildOutput := (s.executor.buildOutput != "" && lastStage)
 	if canGenerateBuildOutput {
 		logrus.Debugf("Generating custom build output with options %q", s.executor.buildOutput)
-		buildOutputOption, err = parse.GetBuildOutput(s.executor.buildOutput)
+		buildOutputOption, err = parse.GetBuildOutput(s.executor.buildOutput, s.executor.output)
 		if err != nil {
 			return "", nil, fmt.Errorf("failed to parse build output: %w", err)
 		}
@@ -2080,6 +2080,14 @@ func (s *StageExecutor) commit(ctx context.Context, createdBy string, emptyLayer
 }
 
 func (s *StageExecutor) generateBuildOutput(buildOutputOpts define.BuildOutputOption) error {
+	if buildOutputOpts.Type == "image" {
+		err := internalUtil.ExportFromReader(nil, s.executor.store, buildOutputOpts)
+		if err != nil {
+			return fmt.Errorf("failed to export build output: %w", err)
+		}
+		return nil
+	}
+
 	extractRootfsOpts := buildah.ExtractRootfsOptions{}
 	if unshare.IsRootless() {
 		// In order to maintain as much parity as possible
@@ -2099,7 +2107,7 @@ func (s *StageExecutor) generateBuildOutput(buildOutputOpts define.BuildOutputOp
 		return fmt.Errorf("failed to extract rootfs from given container image: %w", err)
 	}
 	defer rc.Close()
-	err = internalUtil.ExportFromReader(rc, buildOutputOpts)
+	err = internalUtil.ExportFromReader(rc, s.executor.store, buildOutputOpts)
 	if err != nil {
 		return fmt.Errorf("failed to export build output: %w", err)
 	}

internal/util/util.go

@@ -1,13 +1,17 @@
 package util
 
 import (
+	"context"
 	"fmt"
 	"io"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/containers/buildah/define"
 	"github.com/containers/common/libimage"
+	"github.com/containers/image/v5/transports"
+	"github.com/containers/image/v5/transports/alltransports"
 	"github.com/containers/image/v5/types"
 	encconfig "github.com/containers/ocicrypt/config"
 	enchelpers "github.com/containers/ocicrypt/helpers"
@@ -16,6 +20,7 @@ import (
 	"github.com/containers/storage/pkg/chrootarchive"
 	"github.com/containers/storage/pkg/unshare"
 	v1 "github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/sirupsen/logrus"
 )
 
 // LookupImage returns *Image to corresponding imagename or id
@@ -60,15 +65,51 @@ func GetTempDir() string {
 }
 
 // ExportFromReader reads bytes from given reader and exports to external tar, directory or stdout.
-func ExportFromReader(input io.Reader, opts define.BuildOutputOption) error {
+func ExportFromReader(input io.ReadCloser, store storage.Store, opts define.BuildOutputOption) error {
 	var err error
 	if !filepath.IsAbs(opts.Path) {
 		opts.Path, err = filepath.Abs(opts.Path)
 		if err != nil {
 			return err
 		}
 	}
-	if opts.IsDir {
+	if opts.Type == "image" {
+		if opts.Attrs["push"] != "true" {
+			return nil
+		}
+
+		image := opts.Attrs["name"]
+		destSpec := opts.Attrs["name"]
+		dest, err := alltransports.ParseImageName(destSpec)
+		// add the docker:// transport to see if they neglected it.
+		if err != nil {
+			destTransport := strings.Split(destSpec, ":")[0]
+			if t := transports.Get(destTransport); t != nil {
+				return err
+			}
+
+			if strings.Contains(destSpec, "://") {
+				return err
+			}
+
+			destSpec = "docker://" + destSpec
+			dest2, err2 := alltransports.ParseImageName(destSpec)
+			if err2 != nil {
+				return err
+			}
+			dest = dest2
+			logrus.Debugf("Assuming docker:// as the transport method for DESTINATION: %s", destSpec)
+		}
+
+		libimageOptions := &libimage.PushOptions{}
+		libimageOptions.Writer = os.Stdout
+		runtime, err := libimage.RuntimeFromStore(store, &libimage.RuntimeOptions{SystemContext: &types.SystemContext{}})
+		destString := fmt.Sprintf("%s:%s", dest.Transport().Name(), dest.StringWithinTransport())
+		_, err = runtime.Push(context.Background(), image, destString, libimageOptions)
+		if err != nil {
+			return fmt.Errorf("failed while pushing image %+q: %w", dest, err)
+		}
+	} else if opts.IsDir {
 		// In order to keep this feature as close as possible to
 		// buildkit it was decided to preserve ownership when
 		// invoked as root since caller already has access to artifacts
@@ -89,21 +130,22 @@ func ExportFromReader(input io.Reader, opts define.BuildOutputOption) error {
 		err = chrootarchive.Untar(input, opts.Path, &archive.TarOptions{NoLchown: noLChown})
 		if err != nil {
 			return fmt.Errorf("failed while performing untar at %q: %w", opts.Path, err)
-		}
-	} else {
-		outFile := os.Stdout
-		if !opts.IsStdout {
-			outFile, err = os.Create(opts.Path)
+		} else {
+			outFile := os.Stdout
+			if !opts.IsStdout {
+				outFile, err = os.Create(opts.Path)
+				if err != nil {
+					return fmt.Errorf("failed while creating destination tar at %q: %w", opts.Path, err)
+				}
+				defer outFile.Close()
+			}
+			_, err = io.Copy(outFile, input)
 			if err != nil {
-				return fmt.Errorf("failed while creating destination tar at %q: %w", opts.Path, err)
+				return fmt.Errorf("failed while performing copy to %q: %w", opts.Path, err)
 			}
-			defer outFile.Close()
-		}
-		_, err = io.Copy(outFile, input)
-		if err != nil {
-			return fmt.Errorf("failed while performing copy to %q: %w", opts.Path, err)
 		}
 	}
+
 	return nil
 }
 

pkg/cli/build.go

@@ -292,14 +292,19 @@ func GenBuildOptions(c *cobra.Command, inputArgs []string, iopts BuildOptions) (
 		timestamp = &t
 	}
 	if c.Flag("output").Changed {
-		buildOption, err := parse.GetBuildOutput(iopts.BuildOutput)
+		buildOption, err := parse.GetBuildOutput(iopts.BuildOutput, output)
 		if err != nil {
 			return options, nil, nil, err
 		}
 		if buildOption.IsStdout {
 			iopts.Quiet = true
 		}
 	}
+	if c.Flag("push").Changed {
+		if len(iopts.BuildOutput) == 0 {
+			iopts.BuildOutput = "type=registry"
+		}
+	}
 	var cacheTo []reference.Named
 	var cacheFrom []reference.Named
 	cacheTo = nil
@@ -406,6 +411,7 @@ func GenBuildOptions(c *cobra.Command, inputArgs []string, iopts BuildOptions) (
 		Platforms:               platforms,
 		PullPolicy:              pullPolicy,
 		PullPushRetryDelay:      pullPushRetryDelay,
+		Push:                    iopts.Push,
 		Quiet:                   iopts.Quiet,
 		RemoveIntermediateCtrs:  iopts.Rm,
 		ReportWriter:            reporter,

pkg/cli/common.go

@@ -80,6 +80,7 @@ type BudResults struct {
 	Pull                string
 	PullAlways          bool
 	PullNever           bool
+	Push                bool
 	Quiet               bool
 	IdentityLabel       bool
 	Rm                  bool
@@ -270,6 +271,7 @@ func GetBudFlags(flags *BudResults) pflag.FlagSet {
 	fs.BoolVar(&flags.Stdin, "stdin", false, "pass stdin into containers")
 	fs.StringArrayVarP(&flags.Tag, "tag", "t", []string{}, "tagged `name` to apply to the built image")
 	fs.StringVarP(&flags.BuildOutput, "output", "o", "", "output destination (format: type=local,dest=path)")
+	fs.BoolVar(&flags.Push, "push", false, "Shorthand for `--output=type=registry`")
 	fs.StringVar(&flags.Target, "target", "", "set the target build stage to build")
 	fs.Int64Var(&flags.Timestamp, "timestamp", 0, "set created timestamp to the specified epoch seconds to allow for deterministic builds, defaults to current time")
 	fs.BoolVar(&flags.TLSVerify, "tls-verify", true, "require HTTPS and verify certificates when accessing the registry")

pkg/parse/parse.go

@@ -576,25 +576,30 @@ func AuthConfig(creds string) (*types.DockerAuthConfig, error) {
 
 // GetBuildOutput is responsible for parsing custom build output argument i.e `build --output` flag.
 // Takes `buildOutput` as string and returns BuildOutputOption
-func GetBuildOutput(buildOutput string) (define.BuildOutputOption, error) {
+func GetBuildOutput(buildOutput, image string) (define.BuildOutputOption, error) {
 	if len(buildOutput) == 1 && buildOutput == "-" {
 		// Feature parity with buildkit, output tar to stdout
 		// Read more here: https://docs.docker.com/engine/reference/commandline/build/#custom-build-outputs
 		return define.BuildOutputOption{Path: "",
 			IsDir:    false,
 			IsStdout: true}, nil
 	}
-	if !strings.Contains(buildOutput, ",") {
-		// expect default --output <dirname>
-		return define.BuildOutputOption{Path: buildOutput,
-			IsDir:    true,
-			IsStdout: false}, nil
+
+	// if !strings.Contains(buildOutput, ",") {
+	// 	// expect default --output <dirname>
+	// 	return define.BuildOutputOption{Path: buildOutput,
+	// 		IsDir:    true,
+	// 		IsStdout: false}, nil
+	// }
+
+	out := define.BuildOutputOption{
+		Attrs:    map[string]string{},
+		IsStdout: false,
 	}
+
 	isDir := true
-	isStdout := false
 	typeSelected := false
 	pathSelected := false
-	path := ""
 	tokens := strings.Split(buildOutput, ",")
 	for _, option := range tokens {
 		arr := strings.SplitN(option, "=", 2)
@@ -607,29 +612,36 @@ func GetBuildOutput(buildOutput string) (define.BuildOutputOption, error) {
 				return define.BuildOutputOption{}, fmt.Errorf("duplicate %q not supported", arr[0])
 			}
 			typeSelected = true
-			if arr[1] == "local" {
-				isDir = true
-			} else if arr[1] == "tar" {
-				isDir = false
-			} else {
+			switch arr[1] {
+			case "local":
+				out.IsDir = true
+			case "tar":
+				out.IsDir = false
+			case "registry":
+				out.IsDir = true
+				out.Type = "image"
+				out.Attrs["push"] = "true"
+				out.Attrs["name"] = image
+			default:
 				return define.BuildOutputOption{}, fmt.Errorf("invalid type %q selected for build output options %q", arr[1], buildOutput)
 			}
 		case "dest":
 			if pathSelected {
 				return define.BuildOutputOption{}, fmt.Errorf("duplicate %q not supported", arr[0])
 			}
 			pathSelected = true
-			path = arr[1]
+			out.Path = arr[1]
 		default:
 			return define.BuildOutputOption{}, fmt.Errorf("unrecognized key %q in build output option: %q", arr[0], buildOutput)
 		}
 	}
 
-	if !typeSelected || !pathSelected {
+	if !typeSelected && !pathSelected {
+		// TODO: update error message
 		return define.BuildOutputOption{}, fmt.Errorf("invalid build output option %q, accepted keys are type and dest must be present", buildOutput)
 	}
 
-	if path == "-" {
+	if out.Path == "-" {
 		if isDir {
 			return define.BuildOutputOption{}, fmt.Errorf("invalid build output option %q, type=local and dest=- is not supported", buildOutput)
 		}
@@ -638,7 +650,8 @@ func GetBuildOutput(buildOutput string) (define.BuildOutputOption, error) {
 			IsStdout: true}, nil
 	}
 
-	return define.BuildOutputOption{Path: path, IsDir: isDir, IsStdout: isStdout}, nil
+	return out, nil
+	// return define.BuildOutputOption{Path: path, IsDir: isDir, IsStdout: isStdout}, nil
 }
 
 // IDMappingOptions parses the build options related to user namespaces and ID mapping.