Add a "tag" command

Add a "tag" command, for adding names to locally-stored images.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

Closes: #110
Approved by: rhatdan

cmd/buildah/main.go

@@ -83,6 +83,7 @@ func main() {
 		rmiCommand,
 		budCommand,
 		inspectCommand,
+		tagCommand,
 	}
 	err := app.Run(os.Args)
 	if err != nil {

cmd/buildah/tag.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/projectatomic/buildah/util"
+	"github.com/urfave/cli"
+)
+
+var (
+	tagDescription = "Adds one or more additional names to locally-stored image"
+	tagCommand     = cli.Command{
+		Name:        "tag",
+		Usage:       "Add an additional name to a local image",
+		Description: tagDescription,
+		Action:      tagCmd,
+		ArgsUsage:   "IMAGE-NAME [IMAGE-NAME ...]",
+	}
+)
+
+func tagCmd(c *cli.Context) error {
+	args := c.Args()
+	if len(args) < 2 {
+		return fmt.Errorf("image name and at least one new name must be specified")
+	}
+	store, err := getStore(c)
+	if err != nil {
+		return err
+	}
+	img, err := util.FindImage(store, args[0])
+	if err != nil {
+		return fmt.Errorf("error finding local image %q: %v", args[0], err)
+	}
+	err = util.AddImageNames(store, img, args[1:])
+	if err != nil {
+		return fmt.Errorf("error adding names %v to image %q: %v", args[1:], args[0], err)
+	}
+	return nil
+}

commit.go

@@ -1,15 +1,15 @@
 package buildah
 
 import (
-	"fmt"
 	"io"
 
+	"github.com/Sirupsen/logrus"
 	"github.com/containers/image/copy"
-	"github.com/containers/image/docker/reference"
 	"github.com/containers/image/signature"
 	"github.com/containers/image/storage"
 	"github.com/containers/image/types"
 	"github.com/containers/storage/pkg/archive"
+	"github.com/projectatomic/buildah/util"
 )
 
 // CommitOptions can be used to alter how an image is committed.
@@ -33,23 +33,6 @@ type CommitOptions struct {
 	ReportWriter io.Writer
 }
 
-func expandTags(tags []string) ([]string, error) {
-	expanded := []string{}
-	for _, tag := range tags {
-		name, err := reference.ParseNormalizedNamed(tag)
-		if err != nil {
-			return nil, fmt.Errorf("error parsing tag %q: %v", tag, err)
-		}
-		name = reference.TagNameOnly(name)
-		tag = ""
-		if tagged, ok := name.(reference.NamedTagged); ok {
-			tag = ":" + tagged.Tag()
-		}
-		expanded = append(expanded, name.Name()+tag)
-	}
-	return expanded, nil
-}
-
 // Commit writes the contents of the container, along with its updated
 // configuration, to a new image in the specified location, and if we know how,
 // add any additional tags that were specified.
@@ -67,20 +50,23 @@ func (b *Builder) Commit(dest types.ImageReference, options CommitOptions) error
 		return err
 	}
 	err = copy.Image(policyContext, dest, src, getCopyOptions(options.ReportWriter))
-	switch dest.Transport().Name() {
-	case storage.Transport.Name():
-		tags, err := expandTags(options.AdditionalTags)
 	if err != nil {
 		return err
 	}
+	if len(options.AdditionalTags) > 0 {
+		switch dest.Transport().Name() {
+		case storage.Transport.Name():
 			img, err := storage.Transport.GetStoreImage(b.store, dest)
 			if err != nil {
 				return err
 			}
-		err = b.store.SetNames(img.ID, append(img.Names, tags...))
+			err = util.AddImageNames(b.store, img, options.AdditionalTags)
 			if err != nil {
-			return fmt.Errorf("error setting image names to %v: %v", append(img.Names, tags...), err)
-		}
-	}
 				return err
+			}
+		default:
+			logrus.Warnf("don't know how to add tags to images stored in %q transport", dest.Transport().Name())
+		}
+	}
+	return nil
 }

contrib/completions/bash/buildah

@@ -537,6 +537,19 @@ return 1
      esac
  }
 
+ _buildah_tag() {
+     local options_with_args="
+     "
+
+     local all_options="$options_with_args"
+
+     case "$cur" in
+         -*)
+             COMPREPLY=($(compgen -W "$options_with_args" -- "$cur"))
+             ;;
+     esac
+ }
+
  _buildah_from() {
      local boolean_options="
      --help
@@ -583,6 +596,7 @@ return 1
        rm
        rmi
        run
+       tag
        umount
        unmount
    )

docs/buildah-tag.md

@@ -0,0 +1,18 @@
+## buildah-tag "1" "May 2017" "buildah"
+
+## NAME
+buildah tag - Add additional names to local images.
+
+## SYNOPSIS
+**buildah** **tag** **name** **new-name** [...]
+
+## DESCRIPTION
+Adds additional names to locally-stored images.
+
+## EXAMPLE
+
+buildah tag imageName firstNewName
+buildah tag imageName firstNewName SecondNewName
+
+## SEE ALSO
+buildah(1)

tests/tag.bats

@@ -0,0 +1,19 @@
+#!/usr/bin/env bats
+
+load helpers
+
+@test "tag" {
+  cid=$(buildah from --pull=false --signature-policy ${TESTSDIR}/policy.json scratch)
+  run buildah commit --signature-policy ${TESTSDIR}/policy.json "$cid" scratch-image
+  [ "$status" -eq 0 ]
+  run buildah inspect --type image tagged-image
+  [ "$status" -ne 0 ]
+  run buildah tag scratch-image tagged-image tagged-also-image named-image
+  [ "$status" -eq 0 ]
+  run buildah inspect --type image tagged-image
+  [ "$status" -eq 0 ]
+  run buildah inspect --type image tagged-also-image
+  [ "$status" -eq 0 ]
+  run buildah inspect --type image named-image
+  [ "$status" -eq 0 ]
+}

util/util.go

@@ -0,0 +1,54 @@
+package util
+
+import (
+	"fmt"
+
+	"github.com/containers/image/docker/reference"
+	is "github.com/containers/image/storage"
+	"github.com/containers/storage"
+)
+
+// ExpandTags takes unqualified names, parses them as image names, and returns
+// the fully expanded result, including a tag.
+func ExpandTags(tags []string) ([]string, error) {
+	expanded := []string{}
+	for _, tag := range tags {
+		name, err := reference.ParseNormalizedNamed(tag)
+		if err != nil {
+			return nil, fmt.Errorf("error parsing tag %q: %v", tag, err)
+		}
+		name = reference.TagNameOnly(name)
+		tag = ""
+		if tagged, ok := name.(reference.NamedTagged); ok {
+			tag = ":" + tagged.Tag()
+		}
+		expanded = append(expanded, name.Name()+tag)
+	}
+	return expanded, nil
+}
+
+// FindImage locates the locally-stored image which corresponds to a given name.
+func FindImage(store storage.Store, image string) (*storage.Image, error) {
+	ref, err := is.Transport.ParseStoreReference(store, image)
+	if err != nil {
+		return nil, fmt.Errorf("error parsing reference to image %q: %v", image, err)
+	}
+	img, err := is.Transport.GetStoreImage(store, ref)
+	if err != nil {
+		return nil, fmt.Errorf("unable to locate image: %v", err)
+	}
+	return img, nil
+}
+
+// AddImageNames adds the specified names to the specified image.
+func AddImageNames(store storage.Store, image *storage.Image, addNames []string) error {
+	names, err := ExpandTags(addNames)
+	if err != nil {
+		return err
+	}
+	err = store.SetNames(image.ID, append(image.Names, names...))
+	if err != nil {
+		return fmt.Errorf("error adding names (%v) to image %q: %v", names, image.ID, err)
+	}
+	return nil
+}