Temporarly rework genuinetools/img code for pull/unpack without Docker

pkg/installer/client/imgworker/client.go

@@ -0,0 +1,78 @@
+package imgworker
+
+// FROM Slightly adapted from genuinetools/img worker
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+
+	"github.com/containerd/containerd/namespaces"
+	"github.com/genuinetools/img/types"
+	"github.com/moby/buildkit/control"
+	"github.com/moby/buildkit/session"
+	"github.com/moby/buildkit/util/appcontext"
+	"github.com/moby/buildkit/worker/base"
+	"github.com/pkg/errors"
+)
+
+// Client holds the information for the client we will use for communicating
+// with the buildkit controller.
+type Client struct {
+	backend   string
+	localDirs map[string]string
+	root      string
+
+	sessionManager *session.Manager
+	controller     *control.Controller
+	opts           *base.WorkerOpt
+
+	sess *session.Session
+	ctx  context.Context
+}
+
+// New returns a new client for communicating with the buildkit controller.
+func New(root string) (*Client, error) {
+	// Native backend is fine, our images have just one layer. No need to depend on anything
+	backend := types.NativeBackend
+
+	// Create the root/
+	root = filepath.Join(root, "runc", backend)
+	if err := os.MkdirAll(root, 0700); err != nil {
+		return nil, err
+	}
+	c := &Client{
+		backend:   types.NativeBackend,
+		root:      root,
+		localDirs: nil,
+	}
+
+	if err := c.prepare(); err != nil {
+		return nil, errors.Wrapf(err, "failed preparing client")
+	}
+
+	// Create the start of the client.
+	return c, nil
+}
+
+func (c *Client) Close() {
+	c.sess.Close()
+}
+
+func (c *Client) prepare() error {
+	ctx := appcontext.Context()
+	sess, sessDialer, err := c.Session(ctx)
+	if err != nil {
+		return errors.Wrapf(err, "failed creating Session")
+	}
+	ctx = session.NewContext(ctx, sess.ID())
+	ctx = namespaces.WithNamespace(ctx, "buildkit")
+
+	c.ctx = ctx
+	c.sess = sess
+
+	go func() {
+		sess.Run(ctx, sessDialer)
+	}()
+	return nil
+}

pkg/installer/client/imgworker/pull.go

@@ -0,0 +1,129 @@
+package imgworker
+
+// FROM Slightly adapted from genuinetools/img worker
+
+import (
+	"fmt"
+
+	"github.com/containerd/containerd/images"
+	"github.com/containerd/containerd/platforms"
+	"github.com/docker/distribution/reference"
+	"github.com/moby/buildkit/cache"
+	"github.com/moby/buildkit/exporter"
+	imageexporter "github.com/moby/buildkit/exporter/containerimage"
+	"github.com/moby/buildkit/source"
+	"github.com/moby/buildkit/source/containerimage"
+)
+
+// ListedImage represents an image structure returuned from ListImages.
+// It extends containerd/images.Image with extra fields.
+type ListedImage struct {
+	images.Image
+	ContentSize int64
+}
+
+// Pull retrieves an image from a remote registry.
+func (c *Client) Pull(image string) (*ListedImage, error) {
+
+	ctx := c.ctx
+
+	sm, err := c.getSessionManager()
+	if err != nil {
+		return nil, err
+	}
+	// Parse the image name and tag.
+	named, err := reference.ParseNormalizedNamed(image)
+	if err != nil {
+		return nil, fmt.Errorf("parsing image name %q failed: %v", image, err)
+	}
+	// Add the latest lag if they did not provide one.
+	named = reference.TagNameOnly(named)
+	image = named.String()
+
+	// Get the identifier for the image.
+	identifier, err := source.NewImageIdentifier(image)
+	if err != nil {
+		return nil, err
+	}
+
+	// Create the worker opts.
+	opt, err := c.createWorkerOpt()
+	if err != nil {
+		return nil, fmt.Errorf("creating worker opt failed: %v", err)
+	}
+
+	cm, err := cache.NewManager(cache.ManagerOpt{
+		Snapshotter:    opt.Snapshotter,
+		MetadataStore:  opt.MetadataStore,
+		ContentStore:   opt.ContentStore,
+		LeaseManager:   opt.LeaseManager,
+		GarbageCollect: opt.GarbageCollect,
+		Applier:        opt.Applier,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	// Create the source for the pull.
+	srcOpt := containerimage.SourceOpt{
+		Snapshotter:   opt.Snapshotter,
+		ContentStore:  opt.ContentStore,
+		Applier:       opt.Applier,
+		CacheAccessor: cm,
+		ImageStore:    opt.ImageStore,
+		RegistryHosts: opt.RegistryHosts,
+		LeaseManager:  opt.LeaseManager,
+	}
+	src, err := containerimage.NewSource(srcOpt)
+	if err != nil {
+		return nil, err
+	}
+	s, err := src.Resolve(ctx, identifier, sm)
+	if err != nil {
+		return nil, err
+	}
+	ref, err := s.Snapshot(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	// Create the exporter for the pull.
+	iw, err := imageexporter.NewImageWriter(imageexporter.WriterOpt{
+		Snapshotter:  opt.Snapshotter,
+		ContentStore: opt.ContentStore,
+		Differ:       opt.Differ,
+	})
+	if err != nil {
+		return nil, err
+	}
+	expOpt := imageexporter.Opt{
+		SessionManager: sm,
+		ImageWriter:    iw,
+		Images:         opt.ImageStore,
+		RegistryHosts:  opt.RegistryHosts,
+		LeaseManager:   opt.LeaseManager,
+	}
+	exp, err := imageexporter.New(expOpt)
+	if err != nil {
+		return nil, err
+	}
+	e, err := exp.Resolve(ctx, map[string]string{"name": image})
+	if err != nil {
+		return nil, err
+	}
+	if _, err := e.Export(ctx, exporter.Source{Ref: ref}); err != nil {
+		return nil, err
+	}
+
+	// Get the image.
+	img, err := opt.ImageStore.Get(ctx, image)
+	if err != nil {
+		return nil, fmt.Errorf("getting image %s from image store failed: %v", image, err)
+	}
+	size, err := img.Size(ctx, opt.ContentStore, platforms.Default())
+	if err != nil {
+		return nil, fmt.Errorf("calculating size of image %s failed: %v", img.Name, err)
+	}
+
+	return &ListedImage{Image: img, ContentSize: size}, nil
+}

pkg/installer/client/imgworker/session.go

@@ -0,0 +1,51 @@
+package imgworker
+
+// FROM Slightly adapted from genuinetools/img worker
+
+import (
+	"context"
+	"os"
+
+	"github.com/moby/buildkit/session"
+	"github.com/moby/buildkit/session/auth/authprovider"
+	"github.com/moby/buildkit/session/filesync"
+	"github.com/moby/buildkit/session/testutil"
+	"github.com/pkg/errors"
+)
+
+func (c *Client) getSessionManager() (*session.Manager, error) {
+	if c.sessionManager == nil {
+		var err error
+		c.sessionManager, err = session.NewManager()
+		if err != nil {
+			return nil, err
+		}
+	}
+	return c.sessionManager, nil
+}
+
+// Session creates the session manager and returns the session and it's
+// dialer.
+func (c *Client) Session(ctx context.Context) (*session.Session, session.Dialer, error) {
+	m, err := c.getSessionManager()
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "failed to create session manager")
+	}
+	sessionName := "img"
+	s, err := session.NewSession(ctx, sessionName, "")
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "failed to create session")
+	}
+	syncedDirs := make([]filesync.SyncedDir, 0, len(c.localDirs))
+	for name, d := range c.localDirs {
+		syncedDirs = append(syncedDirs, filesync.SyncedDir{Name: name, Dir: d})
+	}
+	s.Allow(filesync.NewFSSyncProvider(syncedDirs))
+	s.Allow(authprovider.NewDockerAuthProvider(os.Stderr))
+	return s, sessionDialer(s, m), err
+}
+
+func sessionDialer(s *session.Session, m *session.Manager) session.Dialer {
+	// FIXME: rename testutil
+	return session.Dialer(testutil.TestStream(testutil.Handler(m.HandleConn)))
+}

pkg/installer/client/imgworker/unpack.go

@@ -0,0 +1,79 @@
+package imgworker
+
+// FROM Slightly adapted from genuinetools/img worker
+
+import (
+	"errors"
+	"fmt"
+	"os"
+
+	"github.com/containerd/containerd/content"
+	"github.com/containerd/containerd/images"
+	"github.com/containerd/containerd/platforms"
+	"github.com/docker/distribution/reference"
+	"github.com/docker/docker/pkg/archive"
+	"github.com/sirupsen/logrus"
+)
+
+// Unpack exports an image to a rootfs destination directory.
+func (c *Client) Unpack(image, dest string) error {
+
+	ctx := c.ctx
+	if len(dest) < 1 {
+		return errors.New("destination directory for rootfs cannot be empty")
+	}
+
+	if _, err := os.Stat(dest); err == nil {
+		return fmt.Errorf("destination directory already exists: %s", dest)
+	}
+
+	// Parse the image name and tag.
+	named, err := reference.ParseNormalizedNamed(image)
+	if err != nil {
+		return fmt.Errorf("parsing image name %q failed: %v", image, err)
+	}
+	// Add the latest lag if they did not provide one.
+	named = reference.TagNameOnly(named)
+	image = named.String()
+
+	// Create the worker opts.
+	opt, err := c.createWorkerOpt()
+	if err != nil {
+		return fmt.Errorf("creating worker opt failed: %v", err)
+	}
+
+	if opt.ImageStore == nil {
+		return errors.New("image store is nil")
+	}
+
+	img, err := opt.ImageStore.Get(ctx, image)
+	if err != nil {
+		return fmt.Errorf("getting image %s from image store failed: %v", image, err)
+	}
+
+	manifest, err := images.Manifest(ctx, opt.ContentStore, img.Target, platforms.Default())
+	if err != nil {
+		return fmt.Errorf("getting image manifest failed: %v", err)
+	}
+
+	for _, desc := range manifest.Layers {
+		logrus.Debugf("Unpacking layer %s", desc.Digest.String())
+
+		// Read the blob from the content store.
+		layer, err := opt.ContentStore.ReaderAt(ctx, desc)
+		if err != nil {
+			return fmt.Errorf("getting reader for digest %s failed: %v", desc.Digest.String(), err)
+		}
+
+		// Unpack the tarfile to the rootfs path.
+		// FROM: https://godoc.org/github.com/moby/moby/pkg/archive#TarOptions
+		if err := archive.Untar(content.NewReader(layer), dest, &archive.TarOptions{
+			NoLchown:        true,
+			ExcludePatterns: []string{"dev/"}, // prevent 'operation not permitted'
+		}); err != nil {
+			return fmt.Errorf("extracting tar for %s to directory %s failed: %v", desc.Digest.String(), dest, err)
+		}
+	}
+
+	return nil
+}

pkg/installer/client/imgworker/workeropts.go

@@ -0,0 +1,106 @@
+package imgworker
+
+// FROM Slightly adapted from genuinetools/img worker
+
+import (
+	"context"
+	"fmt"
+	"path/filepath"
+
+	"github.com/containerd/containerd/content/local"
+	"github.com/containerd/containerd/diff/apply"
+	"github.com/containerd/containerd/diff/walking"
+	ctdmetadata "github.com/containerd/containerd/metadata"
+	"github.com/containerd/containerd/platforms"
+	"github.com/containerd/containerd/remotes/docker"
+	ctdsnapshot "github.com/containerd/containerd/snapshots"
+	"github.com/containerd/containerd/snapshots/native"
+	"github.com/moby/buildkit/cache/metadata"
+	containerdsnapshot "github.com/moby/buildkit/snapshot/containerd"
+	"github.com/moby/buildkit/util/binfmt_misc"
+	"github.com/moby/buildkit/util/leaseutil"
+	"github.com/moby/buildkit/worker/base"
+	specs "github.com/opencontainers/image-spec/specs-go/v1"
+	bolt "go.etcd.io/bbolt"
+)
+
+// createWorkerOpt creates a base.WorkerOpt to be used for a new worker.
+func (c *Client) createWorkerOpt() (opt base.WorkerOpt, err error) {
+
+	if c.opts != nil {
+		return *c.opts, nil
+	}
+
+	// Create the metadata store.
+	md, err := metadata.NewStore(filepath.Join(c.root, "metadata.db"))
+	if err != nil {
+		return opt, err
+	}
+
+	snapshotRoot := filepath.Join(c.root, "snapshots")
+
+	s, err := native.NewSnapshotter(snapshotRoot)
+	if err != nil {
+		return opt, fmt.Errorf("creating %s snapshotter failed: %v", c.backend, err)
+	}
+
+	// Create the content store locally.
+	contentStore, err := local.NewStore(filepath.Join(c.root, "content"))
+	if err != nil {
+		return opt, err
+	}
+
+	// Open the bolt database for metadata.
+	db, err := bolt.Open(filepath.Join(c.root, "containerdmeta.db"), 0644, nil)
+	if err != nil {
+		return opt, err
+	}
+
+	// Create the new database for metadata.
+	mdb := ctdmetadata.NewDB(db, contentStore, map[string]ctdsnapshot.Snapshotter{
+		c.backend: s,
+	})
+	if err := mdb.Init(context.TODO()); err != nil {
+		return opt, err
+	}
+
+	// Create the image store.
+	imageStore := ctdmetadata.NewImageStore(mdb)
+
+	contentStore = containerdsnapshot.NewContentStore(mdb.ContentStore(), "buildkit")
+
+	id, err := base.ID(c.root)
+	if err != nil {
+		return opt, err
+	}
+
+	xlabels := base.Labels("oci", c.backend)
+
+	var supportedPlatforms []specs.Platform
+	for _, p := range binfmt_misc.SupportedPlatforms(false) {
+		parsed, err := platforms.Parse(p)
+		if err != nil {
+			return opt, err
+		}
+		supportedPlatforms = append(supportedPlatforms, platforms.Normalize(parsed))
+	}
+
+	opt = base.WorkerOpt{
+		ID:             id,
+		Labels:         xlabels,
+		MetadataStore:  md,
+		Snapshotter:    containerdsnapshot.NewSnapshotter(c.backend, mdb.Snapshotter(c.backend), "buildkit", nil),
+		ContentStore:   contentStore,
+		Applier:        apply.NewFileSystemApplier(contentStore),
+		Differ:         walking.NewWalkingDiff(contentStore),
+		ImageStore:     imageStore,
+		Platforms:      supportedPlatforms,
+		RegistryHosts:  docker.ConfigureDefaultRegistries(),
+		LeaseManager:   leaseutil.WithNamespace(ctdmetadata.NewLeaseManager(mdb), "buildkit"),
+		GarbageCollect: mdb.GarbageCollect,
+	}
+
+	c.opts = &opt
+
+	return opt, err
+}