tarball

Overview ¶

Package tarball provides a way to generate images using one or more layer tarballs and an optional template configuration.

An example:

package main

import (
	"context"

	cp "github.com/containers/image/v5/copy"
	"github.com/containers/image/v5/signature"
	"github.com/containers/image/v5/tarball"
	"github.com/containers/image/v5/transports/alltransports"
	"github.com/containers/image/v5/types"
	imgspecv1 "github.com/opencontainers/image-spec/specs-go/v1"
)

func imageFromTarball() {
	src, err := alltransports.ParseImageName("tarball:/var/cache/mock/fedora-26-x86_64/root_cache/cache.tar.gz")
	// - or -
	// src, err := tarball.Transport.ParseReference("/var/cache/mock/fedora-26-x86_64/root_cache/cache.tar.gz")
	if err != nil {
		panic(err)
	}
	updater, ok := src.(tarball.ConfigUpdater)
	if !ok {
		panic("unexpected: a tarball reference should implement tarball.ConfigUpdater")
	}
	config := imgspecv1.Image{
		Config: imgspecv1.ImageConfig{
			Cmd: []string{"/bin/bash"},
		},
	}
	annotations := make(map[string]string)
	annotations[imgspecv1.AnnotationDescription] = "test image built from a mock root cache"
	err = updater.ConfigUpdate(config, annotations)
	if err != nil {
		panic(err)
	}
	dest, err := alltransports.ParseImageName("docker-daemon:mock:latest")
	if err != nil {
		panic(err)
	}

	policy, err := signature.DefaultPolicy(nil)
	if err != nil {
		panic(err)
	}

	pc, err := signature.NewPolicyContext(policy)
	if err != nil {
		panic(err)
	}
	defer pc.Destroy()
	_, err = cp.Image(context.TODO(), pc, dest, src, nil)
	if err != nil {
		panic(err)
	}
}