restic/cmd/restic/cmd_diff.go
Michael Eischer 118a69a84b lock: replace lockRepo(Exclusive) with openWith(Read/Write/Exclusive)Lock
The new functions much better convey the intent behind the lock
request. This allows cleanly integrating noLock (for read) and dryRun
(write/exclusive) handling.

There are only minor changes to existing behavior with two exceptions:
- `tag` no longer accepts the `--no-lock` flag. As it replaces files in
  the repository, this always requires an exclusive lock.
- `debug examine` now returns an error if both `--extract-pack` and
  `--no-lock` are given.
2024-03-28 22:46:33 +01:00

453 lines
11 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, and non-zero if there was any error.
`,
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 "file":
s.Files++
case "dir":
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 "file":
for _, blob := range node.Content {
h := restic.BlobHandle{
ID: blob,
Type: restic.DataBlob,
}
bs.Insert(h)
}
case "dir":
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.ID, h.Type)
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 {
name := path.Join(prefix, node.Name)
if node.Type == "dir" {
name += "/"
}
c.printChange(NewChange(name, mode))
stats.Add(node)
addBlobs(blobs, node)
if node.Type == "dir" {
err := c.printDir(ctx, mode, stats, blobs, name, *node.Subtree)
if err != nil {
Warnf("error: %v\n", err)
}
}
}
return nil
}
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 {
addBlobs(blobs, node)
if node.Type == "dir" {
err := c.collectDir(ctx, blobs, *node.Subtree)
if err != nil {
Warnf("error: %v\n", err)
}
}
}
return nil
}
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 {
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 == "dir" {
name += "/"
}
if node1.Type == "file" &&
node2.Type == "file" &&
!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 == "dir" && node2.Type == "dir" {
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 {
Warnf("error: %v\n", err)
}
}
case t1 && !t2:
prefix := path.Join(prefix, name)
if node1.Type == "dir" {
prefix += "/"
}
c.printChange(NewChange(prefix, "-"))
stats.Removed.Add(node1)
if node1.Type == "dir" {
err := c.printDir(ctx, "-", &stats.Removed, stats.BlobsBefore, prefix, *node1.Subtree)
if err != nil {
Warnf("error: %v\n", err)
}
}
case !t1 && t2:
prefix := path.Join(prefix, name)
if node2.Type == "dir" {
prefix += "/"
}
c.printChange(NewChange(prefix, "+"))
stats.Added.Add(node2)
if node2.Type == "dir" {
err := c.printDir(ctx, "+", &stats.Added, stats.BlobsAfter, prefix, *node2.Subtree)
if err != nil {
Warnf("error: %v\n", err)
}
}
}
}
return nil
}
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
}