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restic/internal/backend/cache/file_test.go
2024-08-10 19:34:49 +02:00

294 lines
6.7 KiB
Go

package cache
import (
"bytes"
"fmt"
"io"
"math/rand"
"os"
"runtime"
"testing"
"time"
"github.com/restic/restic/internal/backend"
"github.com/restic/restic/internal/errors"
"github.com/restic/restic/internal/fs"
"github.com/restic/restic/internal/restic"
rtest "github.com/restic/restic/internal/test"
"golang.org/x/sync/errgroup"
)
func generateRandomFiles(t testing.TB, random *rand.Rand, tpe backend.FileType, c *Cache) restic.IDSet {
ids := restic.NewIDSet()
for i := 0; i < random.Intn(15)+10; i++ {
buf := rtest.Random(random.Int(), 1<<19)
id := restic.Hash(buf)
h := backend.Handle{Type: tpe, Name: id.String()}
if c.Has(h) {
t.Errorf("index %v present before save", id)
}
err := c.save(h, bytes.NewReader(buf))
if err != nil {
t.Fatal(err)
}
ids.Insert(id)
}
return ids
}
// randomID returns a random ID from s.
func randomID(s restic.IDSet) restic.ID {
for id := range s {
return id
}
panic("set is empty")
}
func load(t testing.TB, c *Cache, h backend.Handle) []byte {
rd, inCache, err := c.load(h, 0, 0)
if err != nil {
t.Fatal(err)
}
rtest.Equals(t, true, inCache, "expected inCache flag to be true")
if rd == nil {
t.Fatalf("load() returned nil reader")
}
buf, err := io.ReadAll(rd)
if err != nil {
t.Fatal(err)
}
if err = rd.Close(); err != nil {
t.Fatal(err)
}
return buf
}
func listFiles(t testing.TB, c *Cache, tpe restic.FileType) restic.IDSet {
list, err := c.list(tpe)
if err != nil {
t.Errorf("listing failed: %v", err)
}
return list
}
func clearFiles(t testing.TB, c *Cache, tpe restic.FileType, valid restic.IDSet) {
if err := c.Clear(tpe, valid); err != nil {
t.Error(err)
}
}
func TestFiles(t *testing.T) {
seed := time.Now().Unix()
t.Logf("seed is %v", seed)
random := rand.New(rand.NewSource(seed))
c := TestNewCache(t)
var tests = []restic.FileType{
restic.SnapshotFile,
restic.PackFile,
restic.IndexFile,
}
for _, tpe := range tests {
t.Run(tpe.String(), func(t *testing.T) {
ids := generateRandomFiles(t, random, tpe, c)
id := randomID(ids)
h := backend.Handle{Type: tpe, Name: id.String()}
id2 := restic.Hash(load(t, c, h))
if !id.Equal(id2) {
t.Errorf("wrong data returned, want %v, got %v", id.Str(), id2.Str())
}
if !c.Has(h) {
t.Errorf("cache thinks index %v isn't present", id.Str())
}
list := listFiles(t, c, tpe)
if !ids.Equals(list) {
t.Errorf("wrong list of index IDs returned, want:\n %v\ngot:\n %v", ids, list)
}
clearFiles(t, c, tpe, restic.NewIDSet(id))
list2 := listFiles(t, c, tpe)
ids.Delete(id)
want := restic.NewIDSet(id)
if !list2.Equals(want) {
t.Errorf("ClearIndexes removed indexes, want:\n %v\ngot:\n %v", list2, want)
}
clearFiles(t, c, tpe, restic.NewIDSet())
want = restic.NewIDSet()
list3 := listFiles(t, c, tpe)
if !list3.Equals(want) {
t.Errorf("ClearIndexes returned a wrong list, want:\n %v\ngot:\n %v", want, list3)
}
})
}
}
func TestFileLoad(t *testing.T) {
seed := time.Now().Unix()
t.Logf("seed is %v", seed)
random := rand.New(rand.NewSource(seed))
c := TestNewCache(t)
// save about 5 MiB of data in the cache
data := rtest.Random(random.Int(), 5234142)
id := restic.ID{}
copy(id[:], data)
h := backend.Handle{
Type: restic.PackFile,
Name: id.String(),
}
if err := c.save(h, bytes.NewReader(data)); err != nil {
t.Fatalf("Save() returned error: %v", err)
}
var tests = []struct {
offset int64
length int
}{
{0, 0},
{5, 0},
{32*1024 + 5, 0},
{0, 123},
{0, 64*1024 + 234},
{100, 5234142 - 100},
}
for _, test := range tests {
t.Run(fmt.Sprintf("%v/%v", test.length, test.offset), func(t *testing.T) {
rd, inCache, err := c.load(h, test.length, test.offset)
if err != nil {
t.Fatal(err)
}
rtest.Equals(t, true, inCache, "expected inCache flag to be true")
buf, err := io.ReadAll(rd)
if err != nil {
t.Fatal(err)
}
if err = rd.Close(); err != nil {
t.Fatal(err)
}
o := int(test.offset)
l := test.length
if test.length == 0 {
l = len(data) - o
}
if l > len(data)-o {
l = len(data) - o
}
if len(buf) != l {
t.Fatalf("wrong number of bytes returned: want %d, got %d", l, len(buf))
}
if !bytes.Equal(buf, data[o:o+l]) {
t.Fatalf("wrong data returned, want:\n %02x\ngot:\n %02x", data[o:o+16], buf[:16])
}
})
}
}
// Simulate multiple processes writing to a cache, using goroutines.
//
// The possibility of sharing a cache between multiple concurrent restic
// processes isn't guaranteed in the docs and doesn't always work on Windows, hence the
// check on GOOS. Cache sharing is considered a "nice to have" on POSIX, for now.
//
// The cache first creates a temporary file and then renames it to its final name.
// On Windows renaming internally creates a file handle with a shareMode which
// includes FILE_SHARE_DELETE. The Go runtime opens files without FILE_SHARE_DELETE,
// thus Open(fn) will fail until the file handle used for renaming was closed.
// See https://devblogs.microsoft.com/oldnewthing/20211022-00/?p=105822
// for hints on how to fix this properly.
func TestFileSaveConcurrent(t *testing.T) {
if runtime.GOOS == "windows" {
t.Skip("may not work due to FILE_SHARE_DELETE issue")
}
seed := time.Now().Unix()
t.Logf("seed is %v", seed)
random := rand.New(rand.NewSource(seed))
const nproc = 40
var (
c = TestNewCache(t)
data = rtest.Random(1, 10000)
g errgroup.Group
id restic.ID
)
random.Read(id[:])
h := backend.Handle{
Type: restic.PackFile,
Name: id.String(),
}
for i := 0; i < nproc/2; i++ {
g.Go(func() error { return c.save(h, bytes.NewReader(data)) })
// Can't use load because only the main goroutine may call t.Fatal.
g.Go(func() error {
// The timing is hard to get right, but the main thing we want to
// ensure is ENOENT or nil error.
time.Sleep(time.Duration(100+rand.Intn(200)) * time.Millisecond)
f, _, err := c.load(h, 0, 0)
t.Logf("Load error: %v", err)
switch {
case err == nil:
case errors.Is(err, os.ErrNotExist):
return nil
default:
return err
}
defer func() { _ = f.Close() }()
read, err := io.ReadAll(f)
if err == nil && !bytes.Equal(read, data) {
err = errors.New("mismatch between Save and Load")
}
return err
})
}
rtest.OK(t, g.Wait())
saved := load(t, c, h)
rtest.Equals(t, data, saved)
}
func TestFileSaveAfterDamage(t *testing.T) {
c := TestNewCache(t)
rtest.OK(t, fs.RemoveAll(c.path))
// save a few bytes of data in the cache
data := rtest.Random(123456789, 42)
id := restic.Hash(data)
h := backend.Handle{
Type: restic.PackFile,
Name: id.String(),
}
if err := c.save(h, bytes.NewReader(data)); err == nil {
t.Fatal("Missing error when saving to deleted cache directory")
}
}