Add `tag`: Manipulate tags on existing snapshots

Add integration testing.

src/cmds/restic/cmd_tag.go

@@ -0,0 +1,189 @@
+package main
+
+import (
+	"github.com/spf13/cobra"
+
+	"restic"
+	"restic/debug"
+	"restic/errors"
+	"restic/repository"
+)
+
+var cmdTag = &cobra.Command{
+	Use:   "tag [flags] [snapshot-ID ...]",
+	Short: "modifies tags on snapshots",
+	Long: `
+The "tag" command allows you to modify tags on exiting snapshots.
+
+You can either set/replace the entire set of tags on a snapshot, or
+add tags to/remove tags from the existing set.
+
+When no snapshot-ID is given, all snapshots matching the host, tag and path filter criteria are modified.
+`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return runTag(tagOptions, globalOptions, args)
+	},
+}
+
+// TagOptions bundles all options for the 'tag' command.
+type TagOptions struct {
+	Host       string
+	Paths      []string
+	Tags       []string
+	SetTags    []string
+	AddTags    []string
+	RemoveTags []string
+}
+
+var tagOptions TagOptions
+
+func init() {
+	cmdRoot.AddCommand(cmdTag)
+
+	tagFlags := cmdTag.Flags()
+	tagFlags.StringSliceVar(&tagOptions.SetTags, "set", nil, "`tag` which will replace the existing tags (can be given multiple times)")
+	tagFlags.StringSliceVar(&tagOptions.AddTags, "add", nil, "`tag` which will be added to the existing tags (can be given multiple times)")
+	tagFlags.StringSliceVar(&tagOptions.RemoveTags, "remove", nil, "`tag` which will be removed from the existing tags (can be given multiple times)")
+
+	tagFlags.StringVarP(&tagOptions.Host, "host", "H", "", `only consider snapshots for this host, when no snapshot ID is given`)
+	tagFlags.StringSliceVar(&tagOptions.Tags, "tag", nil, "only consider snapshots which include this `tag`, when no snapshot-ID is given")
+	tagFlags.StringSliceVar(&tagOptions.Paths, "path", nil, "only consider snapshots which include this (absolute) `path`, when no snapshot-ID is given")
+}
+
+func changeTags(repo *repository.Repository, snapshotID restic.ID, setTags, addTags, removeTags, tags, paths []string, host string) (bool, error) {
+	var changed bool
+
+	sn, err := restic.LoadSnapshot(repo, snapshotID)
+	if err != nil {
+		return false, err
+	}
+	if (host != "" && host != sn.Hostname) || !sn.HasTags(tags) || !restic.SamePaths(sn.Paths, paths) {
+		return false, nil
+	}
+
+	if len(setTags) != 0 {
+		// Setting the tag to an empty string really means no more tags.
+		if len(setTags) == 1 && setTags[0] == "" {
+			setTags = nil
+		}
+		sn.Tags = setTags
+		changed = true
+	} else {
+		for _, add := range addTags {
+			found := false
+			for _, tag := range sn.Tags {
+				if tag == add {
+					found = true
+					break
+				}
+			}
+			if !found {
+				sn.Tags = append(sn.Tags, add)
+				changed = true
+			}
+		}
+		for _, remove := range removeTags {
+			for i, tag := range sn.Tags {
+				if tag == remove {
+					// https://github.com/golang/go/wiki/SliceTricks
+					sn.Tags[i] = sn.Tags[len(sn.Tags)-1]
+					sn.Tags[len(sn.Tags)-1] = ""
+					sn.Tags = sn.Tags[:len(sn.Tags)-1]
+
+					changed = true
+					break
+				}
+			}
+		}
+	}
+
+	if changed {
+		// Save the new snapshot.
+		id, err := repo.SaveJSONUnpacked(restic.SnapshotFile, sn)
+		if err != nil {
+			return false, err
+		}
+
+		debug.Log("new snapshot saved as %v", id.Str())
+
+		if err = repo.Flush(); err != nil {
+			return false, err
+		}
+
+		// Remove the old snapshot.
+		h := restic.Handle{Type: restic.SnapshotFile, Name: sn.ID().String()}
+		if err = repo.Backend().Remove(h); err != nil {
+			return false, err
+		}
+
+		debug.Log("old snapshot %v removed", sn.ID())
+	}
+	return changed, nil
+}
+
+func runTag(opts TagOptions, gopts GlobalOptions, args []string) error {
+	if len(opts.SetTags) == 0 && len(opts.AddTags) == 0 && len(opts.RemoveTags) == 0 {
+		return errors.Fatal("nothing to do!")
+	}
+	if len(opts.SetTags) != 0 && (len(opts.AddTags) != 0 || len(opts.RemoveTags) != 0) {
+		return errors.Fatal("--set and --add/--remove cannot be given at the same time")
+	}
+
+	repo, err := OpenRepository(gopts)
+	if err != nil {
+		return err
+	}
+
+	if !gopts.NoLock {
+		Verbosef("Create exclusive lock for repository\n")
+		lock, err := lockRepoExclusive(repo)
+		defer unlockRepo(lock)
+		if err != nil {
+			return err
+		}
+	}
+
+	var ids restic.IDs
+	if len(args) != 0 {
+		// When explit snapshot-IDs are given, the filtering does not matter anymore.
+		opts.Host = ""
+		opts.Tags = nil
+		opts.Paths = nil
+
+		// Process all snapshot IDs given as arguments.
+		for _, s := range args {
+			snapshotID, err := restic.FindSnapshot(repo, s)
+			if err != nil {
+				Warnf("could not find a snapshot for ID %q, ignoring: %v\n", s, err)
+				continue
+			}
+			ids = append(ids, snapshotID)
+		}
+		ids = ids.Uniq()
+	} else {
+		// If there were no arguments, just get all snapshots.
+		done := make(chan struct{})
+		defer close(done)
+		for snapshotID := range repo.List(restic.SnapshotFile, done) {
+			ids = append(ids, snapshotID)
+		}
+	}
+
+	changeCnt := 0
+	for _, id := range ids {
+		changed, err := changeTags(repo, id, opts.SetTags, opts.AddTags, opts.RemoveTags, opts.Tags, opts.Paths, opts.Host)
+		if err != nil {
+			Warnf("unable to modify the tags for snapshot ID %q, ignoring: %v\n", id, err)
+			continue
+		}
+		if changed {
+			changeCnt++
+		}
+	}
+	if changeCnt == 0 {
+		Verbosef("No snapshots were modified\n")
+	} else {
+		Verbosef("Modified tags on %v snapshots\n", changeCnt)
+	}
+	return nil
+}

src/cmds/restic/integration_test.go

@@ -655,6 +655,62 @@ func TestBackupTags(t *testing.T) {
 	})
 }
 
+func testRunTag(t testing.TB, opts TagOptions, gopts GlobalOptions) {
+	OK(t, runTag(opts, gopts, []string{}))
+}
+
+func TestTag(t *testing.T) {
+	withTestEnvironment(t, func(env *testEnvironment, gopts GlobalOptions) {
+		datafile := filepath.Join("testdata", "backup-data.tar.gz")
+		testRunInit(t, gopts)
+		SetupTarTestFixture(t, env.testdata, datafile)
+
+		testRunBackup(t, []string{env.testdata}, BackupOptions{}, gopts)
+		testRunCheck(t, gopts)
+		newest, _ := testRunSnapshots(t, gopts)
+		Assert(t, newest != nil, "expected a new backup, got nil")
+		Assert(t, len(newest.Tags) == 0,
+			"expected no tags, got %v", newest.Tags)
+
+		testRunTag(t, TagOptions{SetTags: []string{"NL"}}, gopts)
+		testRunCheck(t, gopts)
+		newest, _ = testRunSnapshots(t, gopts)
+		Assert(t, newest != nil, "expected a new backup, got nil")
+		Assert(t, len(newest.Tags) == 1 && newest.Tags[0] == "NL",
+			"set failed, expected one NL tag, got %v", newest.Tags)
+
+		testRunTag(t, TagOptions{AddTags: []string{"CH"}}, gopts)
+		testRunCheck(t, gopts)
+		newest, _ = testRunSnapshots(t, gopts)
+		Assert(t, newest != nil, "expected a new backup, got nil")
+		Assert(t, len(newest.Tags) == 2 && newest.Tags[0] == "NL" && newest.Tags[1] == "CH",
+			"add failed, expected CH,NL tags, got %v", newest.Tags)
+
+		testRunTag(t, TagOptions{RemoveTags: []string{"NL"}}, gopts)
+		testRunCheck(t, gopts)
+		newest, _ = testRunSnapshots(t, gopts)
+		Assert(t, newest != nil, "expected a new backup, got nil")
+		Assert(t, len(newest.Tags) == 1 && newest.Tags[0] == "CH",
+			"remove failed, expected one CH tag, got %v", newest.Tags)
+
+		testRunTag(t, TagOptions{AddTags: []string{"US", "RU"}}, gopts)
+		testRunTag(t, TagOptions{RemoveTags: []string{"CH", "US", "RU"}}, gopts)
+		testRunCheck(t, gopts)
+		newest, _ = testRunSnapshots(t, gopts)
+		Assert(t, newest != nil, "expected a new backup, got nil")
+		Assert(t, len(newest.Tags) == 0,
+			"expected no tags, got %v", newest.Tags)
+
+		// Check special case of removing all tags.
+		testRunTag(t, TagOptions{SetTags: []string{""}}, gopts)
+		testRunCheck(t, gopts)
+		newest, _ = testRunSnapshots(t, gopts)
+		Assert(t, newest != nil, "expected a new backup, got nil")
+		Assert(t, len(newest.Tags) == 0,
+			"expected no tags, got %v", newest.Tags)
+	})
+}
+
 func testRunKeyListOtherIDs(t testing.TB, gopts GlobalOptions) []string {
 	buf := bytes.NewBuffer(nil)