restic/cmd/restic/cmd_diff.go
2024-08-31 18:20:01 +02:00

470 lines
12 KiB
Go

package main
import (
"context"
"encoding/json"
"path"
"reflect"
"sort"
"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/errors"
"github.com/restic/restic/internal/restic"
"github.com/restic/restic/internal/ui"
"github.com/spf13/cobra"
)
var cmdDiff = &cobra.Command{
Use: "diff [flags] snapshotID snapshotID",
Short: "Show differences between two snapshots",
Long: `
The "diff" command shows differences from the first to the second snapshot. The
first characters in each line display what has happened to a particular file or
directory:
* + The item was added
* - The item was removed
* U The metadata (access mode, timestamps, ...) for the item was updated
* M The file's content was modified
* T The type was changed, e.g. a file was made a symlink
* ? Bitrot detected: The file's content has changed but all metadata is the same
Metadata comparison will likely not work if a backup was created using the
'--ignore-inode' or '--ignore-ctime' option.
To only compare files in specific subfolders, you can use the
"snapshotID:subfolder" syntax, where "subfolder" is a path within the
snapshot.
EXIT STATUS
===========
Exit status is 0 if the command was successful.
Exit status is 1 if there was any error.
Exit status is 10 if the repository does not exist.
Exit status is 11 if the repository is already locked.
Exit status is 12 if the password is incorrect.
`,
GroupID: cmdGroupDefault,
DisableAutoGenTag: true,
RunE: func(cmd *cobra.Command, args []string) error {
return runDiff(cmd.Context(), diffOptions, globalOptions, args)
},
}
// DiffOptions collects all options for the diff command.
type DiffOptions struct {
ShowMetadata bool
}
var diffOptions DiffOptions
func init() {
cmdRoot.AddCommand(cmdDiff)
f := cmdDiff.Flags()
f.BoolVar(&diffOptions.ShowMetadata, "metadata", false, "print changes in metadata")
}
func loadSnapshot(ctx context.Context, be restic.Lister, repo restic.LoaderUnpacked, desc string) (*restic.Snapshot, string, error) {
sn, subfolder, err := restic.FindSnapshot(ctx, be, repo, desc)
if err != nil {
return nil, "", errors.Fatal(err.Error())
}
return sn, subfolder, err
}
// Comparer collects all things needed to compare two snapshots.
type Comparer struct {
repo restic.BlobLoader
opts DiffOptions
printChange func(change *Change)
}
type Change struct {
MessageType string `json:"message_type"` // "change"
Path string `json:"path"`
Modifier string `json:"modifier"`
}
func NewChange(path string, mode string) *Change {
return &Change{MessageType: "change", Path: path, Modifier: mode}
}
// DiffStat collects stats for all types of items.
type DiffStat struct {
Files int `json:"files"`
Dirs int `json:"dirs"`
Others int `json:"others"`
DataBlobs int `json:"data_blobs"`
TreeBlobs int `json:"tree_blobs"`
Bytes uint64 `json:"bytes"`
}
// Add adds stats information for node to s.
func (s *DiffStat) Add(node *restic.Node) {
if node == nil {
return
}
switch node.Type {
case restic.NodeTypeFile:
s.Files++
case restic.NodeTypeDir:
s.Dirs++
default:
s.Others++
}
}
// addBlobs adds the blobs of node to s.
func addBlobs(bs restic.BlobSet, node *restic.Node) {
if node == nil {
return
}
switch node.Type {
case restic.NodeTypeFile:
for _, blob := range node.Content {
h := restic.BlobHandle{
ID: blob,
Type: restic.DataBlob,
}
bs.Insert(h)
}
case restic.NodeTypeDir:
h := restic.BlobHandle{
ID: *node.Subtree,
Type: restic.TreeBlob,
}
bs.Insert(h)
}
}
type DiffStatsContainer struct {
MessageType string `json:"message_type"` // "statistics"
SourceSnapshot string `json:"source_snapshot"`
TargetSnapshot string `json:"target_snapshot"`
ChangedFiles int `json:"changed_files"`
Added DiffStat `json:"added"`
Removed DiffStat `json:"removed"`
BlobsBefore, BlobsAfter, BlobsCommon restic.BlobSet `json:"-"`
}
// updateBlobs updates the blob counters in the stats struct.
func updateBlobs(repo restic.Loader, blobs restic.BlobSet, stats *DiffStat) {
for h := range blobs {
switch h.Type {
case restic.DataBlob:
stats.DataBlobs++
case restic.TreeBlob:
stats.TreeBlobs++
}
size, found := repo.LookupBlobSize(h.Type, h.ID)
if !found {
Warnf("unable to find blob size for %v\n", h)
continue
}
stats.Bytes += uint64(size)
}
}
func (c *Comparer) printDir(ctx context.Context, mode string, stats *DiffStat, blobs restic.BlobSet, prefix string, id restic.ID) error {
debug.Log("print %v tree %v", mode, id)
tree, err := restic.LoadTree(ctx, c.repo, id)
if err != nil {
return err
}
for _, node := range tree.Nodes {
if ctx.Err() != nil {
return ctx.Err()
}
name := path.Join(prefix, node.Name)
if node.Type == restic.NodeTypeDir {
name += "/"
}
c.printChange(NewChange(name, mode))
stats.Add(node)
addBlobs(blobs, node)
if node.Type == restic.NodeTypeDir {
err := c.printDir(ctx, mode, stats, blobs, name, *node.Subtree)
if err != nil && err != context.Canceled {
Warnf("error: %v\n", err)
}
}
}
return ctx.Err()
}
func (c *Comparer) collectDir(ctx context.Context, blobs restic.BlobSet, id restic.ID) error {
debug.Log("print tree %v", id)
tree, err := restic.LoadTree(ctx, c.repo, id)
if err != nil {
return err
}
for _, node := range tree.Nodes {
if ctx.Err() != nil {
return ctx.Err()
}
addBlobs(blobs, node)
if node.Type == restic.NodeTypeDir {
err := c.collectDir(ctx, blobs, *node.Subtree)
if err != nil && err != context.Canceled {
Warnf("error: %v\n", err)
}
}
}
return ctx.Err()
}
func uniqueNodeNames(tree1, tree2 *restic.Tree) (tree1Nodes, tree2Nodes map[string]*restic.Node, uniqueNames []string) {
names := make(map[string]struct{})
tree1Nodes = make(map[string]*restic.Node)
for _, node := range tree1.Nodes {
tree1Nodes[node.Name] = node
names[node.Name] = struct{}{}
}
tree2Nodes = make(map[string]*restic.Node)
for _, node := range tree2.Nodes {
tree2Nodes[node.Name] = node
names[node.Name] = struct{}{}
}
uniqueNames = make([]string, 0, len(names))
for name := range names {
uniqueNames = append(uniqueNames, name)
}
sort.Strings(uniqueNames)
return tree1Nodes, tree2Nodes, uniqueNames
}
func (c *Comparer) diffTree(ctx context.Context, stats *DiffStatsContainer, prefix string, id1, id2 restic.ID) error {
debug.Log("diffing %v to %v", id1, id2)
tree1, err := restic.LoadTree(ctx, c.repo, id1)
if err != nil {
return err
}
tree2, err := restic.LoadTree(ctx, c.repo, id2)
if err != nil {
return err
}
tree1Nodes, tree2Nodes, names := uniqueNodeNames(tree1, tree2)
for _, name := range names {
if ctx.Err() != nil {
return ctx.Err()
}
node1, t1 := tree1Nodes[name]
node2, t2 := tree2Nodes[name]
addBlobs(stats.BlobsBefore, node1)
addBlobs(stats.BlobsAfter, node2)
switch {
case t1 && t2:
name := path.Join(prefix, name)
mod := ""
if node1.Type != node2.Type {
mod += "T"
}
if node2.Type == restic.NodeTypeDir {
name += "/"
}
if node1.Type == restic.NodeTypeFile &&
node2.Type == restic.NodeTypeFile &&
!reflect.DeepEqual(node1.Content, node2.Content) {
mod += "M"
stats.ChangedFiles++
node1NilContent := *node1
node2NilContent := *node2
node1NilContent.Content = nil
node2NilContent.Content = nil
// the bitrot detection may not work if `backup --ignore-inode` or `--ignore-ctime` were used
if node1NilContent.Equals(node2NilContent) {
// probable bitrot detected
mod += "?"
}
} else if c.opts.ShowMetadata && !node1.Equals(*node2) {
mod += "U"
}
if mod != "" {
c.printChange(NewChange(name, mod))
}
if node1.Type == restic.NodeTypeDir && node2.Type == restic.NodeTypeDir {
var err error
if (*node1.Subtree).Equal(*node2.Subtree) {
err = c.collectDir(ctx, stats.BlobsCommon, *node1.Subtree)
} else {
err = c.diffTree(ctx, stats, name, *node1.Subtree, *node2.Subtree)
}
if err != nil && err != context.Canceled {
Warnf("error: %v\n", err)
}
}
case t1 && !t2:
prefix := path.Join(prefix, name)
if node1.Type == restic.NodeTypeDir {
prefix += "/"
}
c.printChange(NewChange(prefix, "-"))
stats.Removed.Add(node1)
if node1.Type == restic.NodeTypeDir {
err := c.printDir(ctx, "-", &stats.Removed, stats.BlobsBefore, prefix, *node1.Subtree)
if err != nil && err != context.Canceled {
Warnf("error: %v\n", err)
}
}
case !t1 && t2:
prefix := path.Join(prefix, name)
if node2.Type == restic.NodeTypeDir {
prefix += "/"
}
c.printChange(NewChange(prefix, "+"))
stats.Added.Add(node2)
if node2.Type == restic.NodeTypeDir {
err := c.printDir(ctx, "+", &stats.Added, stats.BlobsAfter, prefix, *node2.Subtree)
if err != nil && err != context.Canceled {
Warnf("error: %v\n", err)
}
}
}
}
return ctx.Err()
}
func runDiff(ctx context.Context, opts DiffOptions, gopts GlobalOptions, args []string) error {
if len(args) != 2 {
return errors.Fatalf("specify two snapshot IDs")
}
ctx, repo, unlock, err := openWithReadLock(ctx, gopts, gopts.NoLock)
if err != nil {
return err
}
defer unlock()
// cache snapshots listing
be, err := restic.MemorizeList(ctx, repo, restic.SnapshotFile)
if err != nil {
return err
}
sn1, subfolder1, err := loadSnapshot(ctx, be, repo, args[0])
if err != nil {
return err
}
sn2, subfolder2, err := loadSnapshot(ctx, be, repo, args[1])
if err != nil {
return err
}
if !gopts.JSON {
Verbosef("comparing snapshot %v to %v:\n\n", sn1.ID().Str(), sn2.ID().Str())
}
bar := newIndexProgress(gopts.Quiet, gopts.JSON)
if err = repo.LoadIndex(ctx, bar); err != nil {
return err
}
if sn1.Tree == nil {
return errors.Errorf("snapshot %v has nil tree", sn1.ID().Str())
}
if sn2.Tree == nil {
return errors.Errorf("snapshot %v has nil tree", sn2.ID().Str())
}
sn1.Tree, err = restic.FindTreeDirectory(ctx, repo, sn1.Tree, subfolder1)
if err != nil {
return err
}
sn2.Tree, err = restic.FindTreeDirectory(ctx, repo, sn2.Tree, subfolder2)
if err != nil {
return err
}
c := &Comparer{
repo: repo,
opts: opts,
printChange: func(change *Change) {
Printf("%-5s%v\n", change.Modifier, change.Path)
},
}
if gopts.JSON {
enc := json.NewEncoder(globalOptions.stdout)
c.printChange = func(change *Change) {
err := enc.Encode(change)
if err != nil {
Warnf("JSON encode failed: %v\n", err)
}
}
}
if gopts.Quiet {
c.printChange = func(_ *Change) {}
}
stats := &DiffStatsContainer{
MessageType: "statistics",
SourceSnapshot: args[0],
TargetSnapshot: args[1],
BlobsBefore: restic.NewBlobSet(),
BlobsAfter: restic.NewBlobSet(),
BlobsCommon: restic.NewBlobSet(),
}
stats.BlobsBefore.Insert(restic.BlobHandle{Type: restic.TreeBlob, ID: *sn1.Tree})
stats.BlobsAfter.Insert(restic.BlobHandle{Type: restic.TreeBlob, ID: *sn2.Tree})
err = c.diffTree(ctx, stats, "/", *sn1.Tree, *sn2.Tree)
if err != nil {
return err
}
both := stats.BlobsBefore.Intersect(stats.BlobsAfter)
updateBlobs(repo, stats.BlobsBefore.Sub(both).Sub(stats.BlobsCommon), &stats.Removed)
updateBlobs(repo, stats.BlobsAfter.Sub(both).Sub(stats.BlobsCommon), &stats.Added)
if gopts.JSON {
err := json.NewEncoder(globalOptions.stdout).Encode(stats)
if err != nil {
Warnf("JSON encode failed: %v\n", err)
}
} else {
Printf("\n")
Printf("Files: %5d new, %5d removed, %5d changed\n", stats.Added.Files, stats.Removed.Files, stats.ChangedFiles)
Printf("Dirs: %5d new, %5d removed\n", stats.Added.Dirs, stats.Removed.Dirs)
Printf("Others: %5d new, %5d removed\n", stats.Added.Others, stats.Removed.Others)
Printf("Data Blobs: %5d new, %5d removed\n", stats.Added.DataBlobs, stats.Removed.DataBlobs)
Printf("Tree Blobs: %5d new, %5d removed\n", stats.Added.TreeBlobs, stats.Removed.TreeBlobs)
Printf(" Added: %-5s\n", ui.FormatBytes(uint64(stats.Added.Bytes)))
Printf(" Removed: %-5s\n", ui.FormatBytes(uint64(stats.Removed.Bytes)))
}
return nil
}