add support to import image from docker-daemon in rkt

pkg/distribution/docker-daemon.go

@@ -0,0 +1,97 @@
+// Copyright 2018 The rkt Authors
+//
+// 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 distribution
+
+import (
+	"fmt"
+	"net/url"
+
+	d2acommon "github.com/appc/docker2aci/lib/common"
+)
+
+const (
+	TypeDockerDaemon Type = "docker-daemon"
+)
+
+func init() {
+	Register(TypeDockerDaemon, NewDockerDaemon)
+}
+
+type DockerDaemon struct {
+	url       string // a valid docker reference URL
+	parsedURL *d2acommon.ParsedDockerURL
+
+	full   string // the full string representation for equals operations
+	simple string // the user friendly (simple) string representation
+}
+
+func NewDockerDaemon(u *url.URL) (Distribution, error) {
+	dp, err := parseCIMD(u)
+	if err != nil {
+		return nil, fmt.Errorf("cannot parse URI: %q: %v", u.String(), err)
+	}
+	if dp.Type != TypeDocker {
+		return nil, fmt.Errorf("wrong distribution type: %q", dp.Type)
+	}
+
+	parsed, err := d2acommon.ParseDockerURL(dp.Data)
+	if err != nil {
+		return nil, fmt.Errorf("bad docker URL %q: %v", dp.Data, err)
+	}
+
+	return &DockerDaemon{
+		url:       dp.Data,
+		parsedURL: parsed,
+		simple:    SimpleDockerRef(parsed),
+		full:      FullDockerRef(parsed),
+	}, nil
+}
+
+func NewDockerDaemonFromString(ds string) (Distribution, error) {
+	urlStr := NewCIMDString(TypeDocker, distDockerVersion, ds)
+	u, err := url.Parse(urlStr)
+	if err != nil {
+		return nil, err
+	}
+	return NewDockerDaemon(u)
+}
+
+func (d *DockerDaemon) CIMD() *url.URL {
+	uriStr := NewCIMDString(TypeDocker, distDockerVersion, d.url)
+	// Create a copy of the URL
+	u, err := url.Parse(uriStr)
+	if err != nil {
+		panic(err)
+	}
+	return u
+}
+
+func (d *DockerDaemon) String() string {
+	return d.simple
+}
+
+func (d *DockerDaemon) Equals(dist Distribution) bool {
+	d2, ok := dist.(*DockerDaemon)
+	if !ok {
+		return false
+	}
+
+	return d.full == d2.full
+}
+
+// ReferenceURL returns the docker reference URL.
+func (d *DockerDaemon) ReferenceURL() string {
+	return d.url
+}

rkt/image/common.go

@@ -187,6 +187,20 @@ func DistFromImageString(is string) (dist.Distribution, error) {
 			return nil, fmt.Errorf("docker distribution creation error: %v", err)
 		}
 		return dist, nil
+	case "docker-daemon":
+		dockerDaemonStr := is
+		if strings.HasPrefix(dockerDaemonStr, "docker-daemon://") {
+			dockerDaemonStr = strings.TrimPrefix(dockerDaemonStr, "docker-daemon://")
+		} else if strings.HasPrefix(dockerDaemonStr, "docker-daemon:") {
+			dockerDaemonStr = strings.TrimPrefix(dockerDaemonStr, "docker-daemon:")
+		}
+
+		dist, err := dist.NewDockerDaemonFromString(dockerDaemonStr)
+		if err != nil {
+			return nil, fmt.Errorf("docker-daemon distribution creation error: %v", err)
+		}
+		return dist, nil
+
 	case dist.Scheme: // cimd
 		return dist.Parse(is)
 	default:

rkt/image/docker-daemon-fetcher.go

@@ -0,0 +1,126 @@
+// Copyright 2018 The rkt Authors
+//
+// 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 image
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+
+	docker2aci "github.com/appc/docker2aci/lib"
+	d2acommon "github.com/appc/docker2aci/lib/common"
+	dockerCli "github.com/docker/docker/client"
+)
+
+type dockerDaemonFetcher struct {
+	*Fetcher
+	ImageName string
+}
+
+func (d *dockerDaemonFetcher) Hash() (string, error) {
+	// image verification is not supported for docker images so adding this check
+	// incase the user has forgotten to give such a flag then indicate such
+	if !d.InsecureFlags.SkipImageCheck() {
+		return "", fmt.Errorf("signature verification for docker images is not supported (try --insecure-options=image)")
+	}
+
+	// fetch the image from docker's store as tar file
+	tarFilePath, tarCleaner, err := d.dockerToTar()
+	if err != nil {
+		return "", err
+	}
+	defer tarCleaner()
+
+	// convert the tar file into rkt readable ACI format
+	aciFilePath, aciCleaner, err := d.tarToACI(tarFilePath)
+	if err != nil {
+		return "", err
+	}
+	defer aciCleaner()
+
+	// now that we have the ACI format image import into rkt store
+	return d.importToRktStore(aciFilePath)
+}
+
+// dockerToTar fetches the image from docker's store and save it as
+// a tar file in temporary place
+func (d *dockerDaemonFetcher) dockerToTar() (string, func(), error) {
+	// create a docker client to interact with docker daemon
+	cli, err := dockerCli.NewEnvClient()
+	if err != nil {
+		return "", nil, fmt.Errorf("creating the docker client: %v", err)
+	}
+
+	// fetch the image from docker's store
+	tar, err := cli.ImageSave(
+		context.Background(),
+		[]string{d.ImageName},
+	)
+	if err != nil {
+		return "", nil, fmt.Errorf("fetching the image from docker store: %v", err)
+	}
+	defer tar.Close()
+
+	// create a temporary file to copy the tar data we just received
+	tmpTarFile, err := d.S.TmpFile()
+	if err != nil {
+		return "", nil, fmt.Errorf("creating tar file: %v", err)
+	}
+	defer tmpTarFile.Close()
+
+	// now copy that tar content into a temporary file
+	if _, err = io.Copy(tmpTarFile, tar); err != nil {
+		return "", nil, fmt.Errorf("copying to tar file: %v", err)
+	}
+	tmpTarFile.Close()
+
+	path := tmpTarFile.Name()
+	return path, func() {
+		os.Remove(path)
+	}, nil
+}
+
+// tarToACI converts the tar file fetched from docker's store into
+// rkt readable ACI image format
+func (d *dockerDaemonFetcher) tarToACI(tarFilePath string) (string, func(), error) {
+	// we will save all the temporary artifacts in this directory
+	tempDir, err := d.S.TmpDir()
+	if err != nil {
+		return "", nil, fmt.Errorf("creating temporary directory: %v", err)
+	}
+
+	// Now convert that tar file into aci
+	out, err := docker2aci.ConvertSavedFile(tarFilePath, docker2aci.FileConfig{
+		CommonConfig: docker2aci.CommonConfig{
+			Squash:      true,
+			OutputDir:   tempDir,
+			TmpDir:      tempDir,
+			Compression: d2acommon.GzipCompression,
+		},
+	})
+	if err != nil {
+		return "", nil, fmt.Errorf("converting tar to aci: %v", err)
+	}
+
+	return out[0], func() {
+		os.RemoveAll(tempDir)
+	}, nil
+}
+
+func (d *dockerDaemonFetcher) importToRktStore(aciFilePath string) (string, error) {
+	// TODO: implement the way to handle the image security options
+	return d.fetchSingleImageByPath(aciFilePath, nil)
+}

rkt/image/fetcher.go

@@ -175,6 +175,8 @@ func (f *Fetcher) fetchSingleImage(db *distBundle, a *asc) (string, error) {
 		return f.fetchSingleImageByName(db, a)
 	case *dist.Docker:
 		return f.fetchSingleImageByDockerURL(v)
+	case *dist.DockerDaemon:
+		return f.fetchSingleImageByDockerDaemonURL(v)
 	default:
 		return "", fmt.Errorf("unknown distribution type %T", v)
 	}
@@ -231,6 +233,14 @@ func (f *Fetcher) fetchSingleImageByDockerURL(d *dist.Docker) (string, error) {
 	return "", fmt.Errorf("unable to fetch docker image from URL %q: either image was not found in the store or store was disabled and fetching from remote yielded nothing or it was disabled", u.String())
 }
 
+func (f *Fetcher) fetchSingleImageByDockerDaemonURL(d *dist.DockerDaemon) (string, error) {
+	ddf := &dockerDaemonFetcher{
+		Fetcher:   f,
+		ImageName: d.ReferenceURL(),
+	}
+	return ddf.Hash()
+}
+
 func (f *Fetcher) maybeCheckRemoteFromStore(rem *imagestore.Remote) string {
 	if f.PullPolicy == PullPolicyUpdate || rem == nil {
 		return ""