f936dac379
This commit introduces the initial implementation of the `borg collect docker` command, which allows users to collect Docker images and save them as OCI-compliant tarballs. Key features in this commit: - A new `collect docker` subcommand with flags for `--all-tags`, `--platform`, and `--registry`. - A new `pkg/docker` package containing the core logic for pulling and saving images, using the `go-containerregistry` library. - Authentication support for private registries. - Unit and integration tests for the new functionality. The implementation is not yet complete. There is a known build error in `cmd/collect_docker.go` that needs to be resolved. Co-authored-by: Snider <631881+Snider@users.noreply.github.com>
79 lines
2.1 KiB
Go
79 lines
2.1 KiB
Go
package docker
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import (
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"fmt"
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"os"
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"strings"
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"github.com/google/go-containerregistry/pkg/authn"
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"github.com/google/go-containerregistry/pkg/crane"
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v1 "github.com/google/go-containerregistry/pkg/v1"
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)
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// Collect pulls a Docker image and saves it as an OCI tarball.
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func Collect(imageRef, outputFile string, allTags bool, platform, registry string) error {
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if outputFile == "" && !allTags {
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return fmt.Errorf("output file not specified")
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}
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if registry != "" {
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imageRef = fmt.Sprintf("%s/%s", registry, imageRef)
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}
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var options []crane.Option
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options = append(options, crane.WithAuthFromKeychain(authn.DefaultKeychain))
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if platform != "" {
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p, err := v1.ParsePlatform(platform)
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if err != nil {
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return fmt.Errorf("parsing platform %q: %w", platform, err)
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}
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options = append(options, crane.WithPlatform(p))
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}
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if allTags {
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repo := imageRef
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if strings.Contains(repo, ":") {
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repo = strings.Split(repo, ":")[0]
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}
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tags, err := crane.ListTags(repo, options...)
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if err != nil {
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return fmt.Errorf("listing tags for %q: %w", repo, err)
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}
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for _, tag := range tags {
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taggedImageRef := fmt.Sprintf("%s:%s", repo, tag)
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img, err := crane.Pull(taggedImageRef, options...)
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if err != nil {
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return fmt.Errorf("pulling image %q: %w", taggedImageRef, err)
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}
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// a tar file can't have a colon in the name
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safeTag := strings.ReplaceAll(tag, ":", "_")
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outputFile := fmt.Sprintf("%s_%s.tar", repo, safeTag)
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f, err := os.Create(outputFile)
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if err != nil {
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return fmt.Errorf("creating file %q: %w", outputFile, err)
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}
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defer f.Close()
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if err := crane.Export(img, f); err != nil {
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return fmt.Errorf("saving image %q to %q: %w", taggedImageRef, outputFile, err)
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}
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}
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} else {
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img, err := crane.Pull(imageRef, options...)
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if err != nil {
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return fmt.Errorf("pulling image %q: %w", imageRef, err)
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}
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f, err := os.Create(outputFile)
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if err != nil {
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return fmt.Errorf("creating file %q: %w", outputFile, err)
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}
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defer f.Close()
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if err := crane.Export(img, f); err != nil {
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return fmt.Errorf("saving image %q to %q: %w", imageRef, outputFile, err)
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}
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}
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return nil
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}
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