Add 'cache' command

changelog/unreleased/issue-1721

@@ -0,0 +1,8 @@
+Enhancement: Add `cache` command to list cache dirs
+
+The command `cache` was added, it allows listing restic's cache directoriers
+together with the last usage. It also allows removing old cache dirs without
+having to access a repo, via `restic cache --cleanup`
+
+https://github.com/restic/restic/issues/1721
+https://github.com/restic/restic/pull/1749

cmd/restic/cmd_cache.go

@@ -0,0 +1,122 @@
+package main
+
+import (
+	"fmt"
+	"path/filepath"
+	"sort"
+	"time"
+
+	"github.com/restic/restic/internal/cache"
+	"github.com/restic/restic/internal/errors"
+	"github.com/restic/restic/internal/fs"
+	"github.com/spf13/cobra"
+)
+
+var cmdCache = &cobra.Command{
+	Use:   "cache",
+	Short: "Operate on local cache directories",
+	Long: `
+The "cache" command allows listing and cleaning local cache directories.
+`,
+	DisableAutoGenTag: true,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return runCache(cacheOptions, globalOptions, args)
+	},
+}
+
+// CacheOptions bundles all options for the snapshots command.
+type CacheOptions struct {
+	Cleanup bool
+	MaxAge  uint
+}
+
+var cacheOptions CacheOptions
+
+func init() {
+	cmdRoot.AddCommand(cmdCache)
+
+	f := cmdCache.Flags()
+	f.BoolVar(&cacheOptions.Cleanup, "cleanup", false, "remove old cache directories")
+	f.UintVar(&cacheOptions.MaxAge, "max-age", 30, "max age in `days` for cache directories to be considered old")
+}
+
+func runCache(opts CacheOptions, gopts GlobalOptions, args []string) error {
+	if len(args) > 0 {
+		return errors.Fatal("the cache command has no arguments")
+	}
+
+	if gopts.NoCache {
+		return errors.Fatal("Refusing to do anything, the cache is disabled")
+	}
+
+	var (
+		cachedir = gopts.CacheDir
+		err      error
+	)
+
+	if cachedir == "" {
+		cachedir, err = cache.DefaultDir()
+		if err != nil {
+			return err
+		}
+	}
+
+	if opts.Cleanup || gopts.CleanupCache {
+		oldDirs, err := cache.OlderThan(cachedir, time.Duration(opts.MaxAge)*24*time.Hour)
+		if err != nil {
+			return err
+		}
+
+		if len(oldDirs) == 0 {
+			Verbosef("no old cache dirs found\n")
+			return nil
+		}
+
+		Verbosef("remove %d old cache directories\n", len(oldDirs))
+
+		for _, item := range oldDirs {
+			dir := filepath.Join(cachedir, item.Name())
+			err = fs.RemoveAll(dir)
+			if err != nil {
+				Warnf("unable to remove %v: %v\n", dir, err)
+			}
+		}
+
+		return nil
+	}
+
+	tab := NewTable()
+	tab.Header = fmt.Sprintf("%-14s   %-16s %s", "Repository ID", "Last Used", "Old")
+	tab.RowFormat = "%-14s   %-16s %s"
+
+	dirs, err := cache.All(cachedir)
+	if err != nil {
+		return err
+	}
+
+	if len(dirs) == 0 {
+		Printf("no cache dirs found, basedir is %v\n", cachedir)
+		return nil
+	}
+
+	sort.Slice(dirs, func(i, j int) bool {
+		return dirs[i].ModTime().Before(dirs[j].ModTime())
+	})
+
+	for _, entry := range dirs {
+		var old string
+		if cache.IsOld(entry.ModTime(), time.Duration(opts.MaxAge)*24*time.Hour) {
+			old = "yes"
+		}
+
+		tab.Rows = append(tab.Rows, []interface{}{
+			entry.Name()[:10],
+			fmt.Sprintf("%d days ago", uint(time.Since(entry.ModTime()).Hours()/24)),
+			old,
+		})
+	}
+
+	tab.Write(gopts.stdout)
+
+	return nil
+}

cmd/restic/global.go

@@ -390,7 +390,7 @@ func OpenRepository(opts GlobalOptions) (*repository.Repository, error) {
 		Printf("removing %d old cache dirs from %v\n", len(oldCacheDirs), c.Base)
 
 		for _, item := range oldCacheDirs {
-			dir := filepath.Join(c.Base, item)
+			dir := filepath.Join(c.Base, item.Name())
 			err = fs.RemoveAll(dir)
 			if err != nil {
 				Warnf("unable to remove %v: %v\n", dir, err)

internal/cache/cache.go

@@ -5,6 +5,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strconv"
 	"time"
 
@@ -156,14 +157,25 @@ func updateTimestamp(d string) error {
 	return fs.Chtimes(d, t, t)
 }
 
-const maxCacheAge = 30 * 24 * time.Hour
+// MaxCacheAge is the default age (30 days) after which cache directories are considered old.
+const MaxCacheAge = 30 * 24 * time.Hour
 
-// Old returns a list of cache directories with a modification time of more
-// than 30 days ago.
-func Old(basedir string) ([]string, error) {
-	var oldCacheDirs []string
+func validCacheDirName(s string) bool {
+	r := regexp.MustCompile(`^[a-fA-F0-9]{64}$`)
+	if !r.MatchString(s) {
+		return false
+	}
 
+	return true
+}
+
+// listCacheDirs returns the list of cache directories.
+func listCacheDirs(basedir string) ([]os.FileInfo, error) {
 	f, err := fs.Open(basedir)
+	if err != nil && os.IsNotExist(errors.Cause(err)) {
+		return nil, nil
+	}
+
 	if err != nil {
 		return nil, err
 	}
@@ -173,29 +185,65 @@ func Old(basedir string) ([]string, error) {
 		return nil, err
 	}
 
-	oldest := time.Now().Add(-maxCacheAge)
-	for _, fi := range entries {
-		if !fi.IsDir() {
-			continue
-		}
-
-		if !fi.ModTime().Before(oldest) {
-			continue
-		}
-
-		oldCacheDirs = append(oldCacheDirs, fi.Name())
-	}
-
 	err = f.Close()
 	if err != nil {
 		return nil, err
 	}
 
+	result := make([]os.FileInfo, 0, len(entries))
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			continue
+		}
+
+		if !validCacheDirName(entry.Name()) {
+			continue
+		}
+
+		result = append(result, entry)
+	}
+
+	return result, nil
+}
+
+// All returns a list of cache directories.
+func All(basedir string) (dirs []os.FileInfo, err error) {
+	return listCacheDirs(basedir)
+}
+
+// OlderThan returns the list of cache directories older than max.
+func OlderThan(basedir string, max time.Duration) ([]os.FileInfo, error) {
+	entries, err := listCacheDirs(basedir)
+	if err != nil {
+		return nil, err
+	}
+
+	var oldCacheDirs []os.FileInfo
+	for _, fi := range entries {
+		if !IsOld(fi.ModTime(), max) {
+			continue
+		}
+
+		oldCacheDirs = append(oldCacheDirs, fi)
+	}
+
 	debug.Log("%d old cache dirs found", len(oldCacheDirs))
 
 	return oldCacheDirs, nil
 }
 
+// Old returns a list of cache directories with a modification time of more
+// than 30 days ago.
+func Old(basedir string) ([]os.FileInfo, error) {
+	return OlderThan(basedir, MaxCacheAge)
+}
+
+// IsOld returns true if the timestamp is considered old.
+func IsOld(t time.Time, maxAge time.Duration) bool {
+	oldest := time.Now().Add(-maxAge)
+	return t.Before(oldest)
+}
+
 // errNoSuchFile is returned when a file is not cached.
 type errNoSuchFile struct {
 	Type string