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// Copyright 2018 Google LLC All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package cmd
import (
"errors"
"fmt"
"log"
"github.com/google/go-containerregistry/pkg/crane"
"github.com/google/go-containerregistry/pkg/logs"
"github.com/google/go-containerregistry/pkg/name"
v1 "github.com/google/go-containerregistry/pkg/v1"
"github.com/google/go-containerregistry/pkg/v1/mutate"
specsv1 "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/spf13/cobra"
)
// NewCmdRebase creates a new cobra.Command for the rebase subcommand.
func NewCmdRebase(options *[]crane.Option) *cobra.Command {
var orig, oldBase, newBase, rebased string
rebaseCmd := &cobra.Command{
Use: "rebase",
Short: "Rebase an image onto a new base image",
Args: cobra.MinimumNArgs(1),
RunE: func(cmd *cobra.Command, args []string) error {
if orig == "" {
orig = args[0]
} else if len(args) != 0 || args[0] != "" {
return fmt.Errorf("cannot use --original with positional argument")
}
// If the new ref isn't provided, write over the original image.
// If that ref was provided by digest (e.g., output from
// another crane command), then strip that and push the
// mutated image by digest instead.
if rebased == "" {
rebased = orig
}
// Stupid hack to support insecure flag.
nameOpt := []name.Option{}
if ok, err := cmd.Parent().PersistentFlags().GetBool("insecure"); err != nil {
log.Fatalf("flag problems: %v", err)
} else if ok {
nameOpt = append(nameOpt, name.Insecure)
}
r, err := name.ParseReference(rebased, nameOpt...)
if err != nil {
log.Fatalf("parsing %s: %v", rebased, err)
}
desc, err := crane.Head(orig, *options...)
if err != nil {
log.Fatalf("checking %s: %v", orig, err)
}
if !cmd.Parent().PersistentFlags().Changed("platform") && desc.MediaType.IsIndex() {
log.Fatalf("rebasing an index is not yet supported")
}
origImg, err := crane.Pull(orig, *options...)
if err != nil {
return err
}
origMf, err := origImg.Manifest()
if err != nil {
return err
}
anns := origMf.Annotations
if newBase == "" && anns != nil {
newBase = anns[specsv1.AnnotationBaseImageName]
}
if newBase == "" {
return errors.New("could not determine new base image from annotations")
}
newBaseRef, err := name.ParseReference(newBase)
if err != nil {
return err
}
if oldBase == "" && anns != nil {
oldBaseDigest := anns[specsv1.AnnotationBaseImageDigest]
oldBase = newBaseRef.Context().Digest(oldBaseDigest).String()
}
if oldBase == "" {
return errors.New("could not determine old base image by digest from annotations")
}
rebasedImg, err := rebaseImage(origImg, oldBase, newBase, *options...)
if err != nil {
return fmt.Errorf("rebasing image: %w", err)
}
rebasedDigest, err := rebasedImg.Digest()
if err != nil {
return fmt.Errorf("digesting new image: %w", err)
}
origDigest, err := origImg.Digest()
if err != nil {
return err
}
if rebasedDigest == origDigest {
logs.Warn.Println("rebasing was no-op")
}
if _, ok := r.(name.Digest); ok {
rebased = r.Context().Digest(rebasedDigest.String()).String()
}
logs.Progress.Println("pushing rebased image as", rebased)
if err := crane.Push(rebasedImg, rebased, *options...); err != nil {
log.Fatalf("pushing %s: %v", rebased, err)
}
fmt.Println(r.Context().Digest(rebasedDigest.String()))
return nil
},
}
rebaseCmd.Flags().StringVar(&orig, "original", "", "Original image to rebase (DEPRECATED: use positional arg instead)")
rebaseCmd.Flags().StringVar(&oldBase, "old_base", "", "Old base image to remove")
rebaseCmd.Flags().StringVar(&newBase, "new_base", "", "New base image to insert")
rebaseCmd.Flags().StringVar(&rebased, "rebased", "", "Tag to apply to rebased image (DEPRECATED: use --tag)")
rebaseCmd.Flags().StringVarP(&rebased, "tag", "t", "", "Tag to apply to rebased image")
return rebaseCmd
}
// rebaseImage parses the references and uses them to perform a rebase on the
// original image.
//
// If oldBase or newBase are "", rebaseImage attempts to derive them using
// annotations in the original image. If those annotations are not found,
// rebaseImage returns an error.
//
// If rebasing is successful, base image annotations are set on the resulting
// image to facilitate implicit rebasing next time.
func rebaseImage(orig v1.Image, oldBase, newBase string, opt ...crane.Option) (v1.Image, error) {
m, err := orig.Manifest()
if err != nil {
return nil, err
}
if newBase == "" && m.Annotations != nil {
newBase = m.Annotations[specsv1.AnnotationBaseImageName]
if newBase != "" {
logs.Debug.Printf("Detected new base from %q annotation: %s", specsv1.AnnotationBaseImageName, newBase)
}
}
if newBase == "" {
return nil, fmt.Errorf("either new base or %q annotation is required", specsv1.AnnotationBaseImageName)
}
newBaseImg, err := crane.Pull(newBase, opt...)
if err != nil {
return nil, err
}
if oldBase == "" && m.Annotations != nil {
oldBase = m.Annotations[specsv1.AnnotationBaseImageDigest]
if oldBase != "" {
newBaseRef, err := name.ParseReference(newBase)
if err != nil {
return nil, err
}
oldBase = newBaseRef.Context().Digest(oldBase).String()
logs.Debug.Printf("Detected old base from %q annotation: %s", specsv1.AnnotationBaseImageDigest, oldBase)
}
}
if oldBase == "" {
return nil, fmt.Errorf("either old base or %q annotation is required", specsv1.AnnotationBaseImageDigest)
}
oldBaseImg, err := crane.Pull(oldBase, opt...)
if err != nil {
return nil, err
}
// NB: if newBase is an index, we need to grab the index's digest to
// annotate the resulting image, even though we pull the
// platform-specific image to rebase.
// crane.Digest will pull a platform-specific image, so use crane.Head
// here instead.
newBaseDesc, err := crane.Head(newBase, opt...)
if err != nil {
return nil, err
}
newBaseDigest := newBaseDesc.Digest.String()
rebased, err := mutate.Rebase(orig, oldBaseImg, newBaseImg)
if err != nil {
return nil, err
}
// Update base image annotations for the new image manifest.
logs.Debug.Printf("Setting annotation %q: %q", specsv1.AnnotationBaseImageDigest, newBaseDigest)
logs.Debug.Printf("Setting annotation %q: %q", specsv1.AnnotationBaseImageName, newBase)
return mutate.Annotations(rebased, map[string]string{
specsv1.AnnotationBaseImageDigest: newBaseDigest,
specsv1.AnnotationBaseImageName: newBase,
}).(v1.Image), nil
}
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