Add support for docker-archive: to skopeo list-tags

Signed-off-by: zhangguanzhang <zhangguanzhang@qq.com>

cmd/skopeo/list_tags.go

@@ -5,10 +5,12 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"sort"
 	"strings"
 
 	"github.com/containers/common/pkg/retry"
 	"github.com/containers/image/v5/docker"
+	"github.com/containers/image/v5/docker/archive"
 	"github.com/containers/image/v5/docker/reference"
 	"github.com/containers/image/v5/transports/alltransports"
 	"github.com/containers/image/v5/types"
@@ -18,7 +20,7 @@ import (
 
 // tagListOutput is the output format of (skopeo list-tags), primarily so that we can format it with a simple json.MarshalIndent.
 type tagListOutput struct {
-	Repository string
+	Repository string `json:",omitempty"`
 	Tags       []string
 }
 
@@ -28,6 +30,21 @@ type tagsOptions struct {
 	retryOpts *retry.RetryOptions
 }
 
+var transportHandlers = map[string]func(ctx context.Context, sys *types.SystemContext, opts *tagsOptions, userInput string) (repositoryName string, tagListing []string, err error){
+	docker.Transport.Name():  listDockerRepoTags,
+	archive.Transport.Name(): listDockerArchiveTags,
+}
+
+// supportedTransports returns all the supported transports
+func supportedTransports(joinStr string) string {
+	res := make([]string, 0, len(transportHandlers))
+	for handlerName := range transportHandlers {
+		res = append(res, handlerName)
+	}
+	sort.Strings(res)
+	return strings.Join(res, joinStr)
+}
+
 func tagsCmd(global *globalOptions) *cobra.Command {
 	sharedFlags, sharedOpts := sharedImageFlags()
 	imageFlags, imageOpts := dockerImageFlags(global, sharedOpts, nil, "", "")
@@ -38,13 +55,14 @@ func tagsCmd(global *globalOptions) *cobra.Command {
 		image:     imageOpts,
 		retryOpts: retryOpts,
 	}
+
 	cmd := &cobra.Command{
-		Use:   "list-tags [command options] REPOSITORY-NAME",
-		Short: "List tags in the transport/repository specified by the REPOSITORY-NAME",
-		Long: `Return the list of tags from the transport/repository "REPOSITORY-NAME"
+		Use:   "list-tags [command options] SOURCE-IMAGE",
+		Short: "List tags in the transport/repository specified by the SOURCE-IMAGE",
+		Long: `Return the list of tags from the transport/repository "SOURCE-IMAGE"
 
 Supported transports:
-docker
+` + supportedTransports(" ") + `
 
 See skopeo-list-tags(1) section "REPOSITORY NAMES" for the expected format
 `,
@@ -95,6 +113,58 @@ func listDockerTags(ctx context.Context, sys *types.SystemContext, imgRef types.
 	return repositoryName, tags, nil
 }
 
+// return the tagLists from a docker repo
+func listDockerRepoTags(ctx context.Context, sys *types.SystemContext, opts *tagsOptions, userInput string) (repositoryName string, tagListing []string, err error) {
+	// Do transport-specific parsing and validation to get an image reference
+	imgRef, err := parseDockerRepositoryReference(userInput)
+	if err != nil {
+		return
+	}
+	if err = retry.RetryIfNecessary(ctx, func() error {
+		repositoryName, tagListing, err = listDockerTags(ctx, sys, imgRef)
+		return err
+	}, opts.retryOpts); err != nil {
+		return
+	}
+	return
+}
+
+// return the tagLists from a docker archive file
+func listDockerArchiveTags(ctx context.Context, sys *types.SystemContext, opts *tagsOptions, userInput string) (repositoryName string, tagListing []string, err error) {
+	ref, err := alltransports.ParseImageName(userInput)
+	if err != nil {
+		return
+	}
+
+	tarReader, _, err := archive.NewReaderForReference(sys, ref)
+	if err != nil {
+		return
+	}
+	defer tarReader.Close()
+
+	imageRefs, err := tarReader.List()
+	if err != nil {
+		return
+	}
+
+	var repoTags []string
+	for imageIndex, items := range imageRefs {
+		for _, ref := range items {
+			repoTags, err = tarReader.ManifestTagsForReference(ref)
+			if err != nil {
+				return
+			}
+			// handle for each untagged image
+			if len(repoTags) == 0 {
+				repoTags = []string{fmt.Sprintf("@%d", imageIndex)}
+			}
+			tagListing = append(tagListing, repoTags...)
+		}
+	}
+
+	return
+}
+
 func (opts *tagsOptions) run(args []string, stdout io.Writer) (retErr error) {
 	ctx, cancel := opts.global.commandTimeoutContext()
 	defer cancel()
@@ -113,23 +183,17 @@ func (opts *tagsOptions) run(args []string, stdout io.Writer) (retErr error) {
 		return fmt.Errorf("Invalid %q: does not specify a transport", args[0])
 	}
 
-	if transport.Name() != docker.Transport.Name() {
-		return fmt.Errorf("Unsupported transport '%v' for tag listing. Only '%v' currently supported", transport.Name(), docker.Transport.Name())
-	}
-
-	// Do transport-specific parsing and validation to get an image reference
-	imgRef, err := parseDockerRepositoryReference(args[0])
-	if err != nil {
-		return err
-	}
-
 	var repositoryName string
 	var tagListing []string
-	if err = retry.RetryIfNecessary(ctx, func() error {
-		repositoryName, tagListing, err = listDockerTags(ctx, sys, imgRef)
-		return err
-	}, opts.retryOpts); err != nil {
-		return err
+
+	if val, ok := transportHandlers[transport.Name()]; ok {
+		repositoryName, tagListing, err = val(ctx, sys, opts, args[0])
+		if err != nil {
+			return err
+		}
+	} else {
+		return fmt.Errorf("Unsupported transport '%s' for tag listing. Only supported: %s",
+			transport.Name(), supportedTransports(", "))
 	}
 
 	outputData := tagListOutput{

docs/skopeo-list-tags.1.md

@@ -1,14 +1,14 @@
 % skopeo-list-tags(1)
 
 ## NAME
-skopeo\-list\-tags - List tags in the transport-specific image repository.
+skopeo\-list\-tags - List image names in a transport-specific collection of images.
 
 ## SYNOPSIS
-**skopeo list-tags** [*options*] _repository-name_
+**skopeo list-tags** [*options*] _source-image_
 
-Return a list of tags from _repository-name_ in a registry.
+Return a list of tags from _source-image_ in a registry or a local docker-archive file.
 
-  _repository-name_ name of repository to retrieve tag listing from
+  _source-image_ name of the repository to retrieve a tag listing from or a local docker-archive file.
 
 ## OPTIONS
 
@@ -53,7 +53,7 @@ The password to access the registry.
 
 ## REPOSITORY NAMES
 
-Repository names are transport-specific references as each transport may have its own concept of a "repository" and "tags". Currently, only the Docker transport is supported.
+Repository names are transport-specific references as each transport may have its own concept of a "repository" and "tags".
 
 This commands refers to repositories using a _transport_`:`_details_ format. The following formats are supported:
 
@@ -72,6 +72,8 @@ This commands refers to repositories using a _transport_`:`_details_ format. The
         "docker.io/myuser/myimage:v1.0"
         "docker.io/myuser/myimage@sha256:f48c4cc192f4c3c6a069cb5cca6d0a9e34d6076ba7c214fd0cc3ca60e0af76bb"
 
+  **docker-archive:path[:docker-reference]
+  more than one images were stored in a docker save-formatted file. 
 
 ## EXAMPLES
 
@@ -121,8 +123,48 @@ $ skopeo list-tags docker://localhost:5000/fedora
 
 ```
 
+### Docker-archive Transport
+
+To list the tags in a local docker-archive file:
+
+```sh
+$ skopeo list-tags docker-archive:/tmp/busybox.tar.gz
+{
+    "Tags": [
+        "busybox:1.28.3"
+    ]
+}
+```
+
+Also supports more than one tags in an archive:
+
+```sh
+$ skopeo list-tags docker-archive:/tmp/docker-two-images.tar.gz
+{
+    "Tags": [
+        "example.com/empty:latest",
+        "example.com/empty/but:different"
+    ]
+}
+```
+
+Will include a source-index entry for each untagged image:
+
+```sh
+$ skopeo list-tags docker-archive:/tmp/four-tags-with-an-untag.tar
+{
+    "Tags": [
+        "image1:tag1",
+        "image2:tag2",
+        "@2",
+        "image4:tag4"
+    ]
+}
+```
+
+
 # SEE ALSO
-skopeo(1), skopeo-login(1), docker-login(1), containers-auth.json(5)
+skopeo(1), skopeo-login(1), docker-login(1), containers-auth.json(5), containers-transports(1)
 
 ## AUTHORS
 

docs/skopeo.1.md

@@ -102,7 +102,7 @@ Print the version number
 | [skopeo-copy(1)](skopeo-copy.1.md)        | Copy an image (manifest, filesystem layers, signatures) from one location to another. |
 | [skopeo-delete(1)](skopeo-delete.1.md)    | Mark the _image-name_ for later deletion by the registry's garbage collector.  |
 | [skopeo-inspect(1)](skopeo-inspect.1.md)  | Return low-level information about _image-name_ in a registry.                 |
-| [skopeo-list-tags(1)](skopeo-list-tags.1.md)  | List tags in the transport-specific image repository.                      |
+| [skopeo-list-tags(1)](skopeo-list-tags.1.md)  | List image names in a transport-specific collection of images.|
 | [skopeo-login(1)](skopeo-login.1.md)  | Login to a container registry. |
 | [skopeo-logout(1)](skopeo-logout.1.md)  | Logout of a container registry. |
 | [skopeo-manifest-digest(1)](skopeo-manifest-digest.1.md)    | Compute a manifest digest for a manifest-file and write it to standard output. |

systemtest/070-list-tags.bats

@@ -0,0 +1,28 @@
+#!/usr/bin/env bats
+#
+# list-tags tests
+#
+
+load helpers
+
+# list from registry
+@test "list-tags: remote repository on a registry" {
+    local remote_image=quay.io/libpod/alpine_labels
+
+    run_skopeo list-tags "docker://${remote_image}"
+    expect_output --substring "quay.io/libpod/alpine_labels"
+    expect_output --substring "latest"
+}
+
+# list from a local docker-archive file
+@test "list-tags: from a docker-archive file" {
+    local file_name=${TEST_SOURCE_DIR}/testdata/docker-two-images.tar.xz
+
+    run_skopeo list-tags docker-archive:$file_name
+    expect_output --substring "example.com/empty:latest"
+    expect_output --substring "example.com/empty/but:different"
+
+}
+
+
+# vim: filetype=sh