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As mentioned in issue [#1560](https://github.com/restic/restic/pull/1560#issuecomment-364689346) this changes the signature for `backend.Save()`. It now takes a parameter of interface type `RewindReader`, so that the backend implementations or our `RetryBackend` middleware can reset the reader to the beginning and then retry an upload operation. The `RewindReader` interface also provides a `Length()` method, which is used in the backend to get the size of the data to be saved. This removes several ugly hacks we had to do to pull the size back out of the `io.Reader` passed to `Save()` before. In the `s3` and `rest` backend this is actively used.
250 lines
5.6 KiB
Go
250 lines
5.6 KiB
Go
package backend
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import (
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"bytes"
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"context"
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"io"
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"io/ioutil"
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"testing"
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"github.com/restic/restic/internal/errors"
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"github.com/restic/restic/internal/mock"
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"github.com/restic/restic/internal/restic"
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"github.com/restic/restic/internal/test"
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)
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func TestBackendSaveRetry(t *testing.T) {
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buf := bytes.NewBuffer(nil)
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errcount := 0
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be := &mock.Backend{
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SaveFn: func(ctx context.Context, h restic.Handle, rd restic.RewindReader) error {
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if errcount == 0 {
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errcount++
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_, err := io.CopyN(ioutil.Discard, rd, 120)
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if err != nil {
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return err
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}
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return errors.New("injected error")
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}
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_, err := io.Copy(buf, rd)
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return err
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},
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}
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retryBackend := RetryBackend{
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Backend: be,
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}
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data := test.Random(23, 5*1024*1024+11241)
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err := retryBackend.Save(context.TODO(), restic.Handle{}, restic.NewByteReader(data))
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if err != nil {
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t.Fatal(err)
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}
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if len(data) != buf.Len() {
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t.Errorf("wrong number of bytes written: want %d, got %d", len(data), buf.Len())
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}
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if !bytes.Equal(data, buf.Bytes()) {
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t.Errorf("wrong data written to backend")
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}
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}
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func TestBackendListRetry(t *testing.T) {
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const (
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ID1 = "id1"
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ID2 = "id2"
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)
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retry := 0
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be := &mock.Backend{
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ListFn: func(ctx context.Context, t restic.FileType, fn func(restic.FileInfo) error) error {
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// fail during first retry, succeed during second
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retry++
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if retry == 1 {
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fn(restic.FileInfo{Name: ID1})
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return errors.New("test list error")
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}
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fn(restic.FileInfo{Name: ID1})
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fn(restic.FileInfo{Name: ID2})
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return nil
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},
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}
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retryBackend := RetryBackend{
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Backend: be,
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}
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var listed []string
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err := retryBackend.List(context.TODO(), restic.DataFile, func(fi restic.FileInfo) error {
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listed = append(listed, fi.Name)
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return nil
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})
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test.OK(t, err) // assert overall success
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test.Equals(t, 2, retry) // assert retried once
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test.Equals(t, []string{ID1, ID2}, listed) // assert no duplicate files
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}
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func TestBackendListRetryErrorFn(t *testing.T) {
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var names = []string{"id1", "id2", "foo", "bar"}
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be := &mock.Backend{
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ListFn: func(ctx context.Context, tpe restic.FileType, fn func(restic.FileInfo) error) error {
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t.Logf("List called for %v", tpe)
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for _, name := range names {
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err := fn(restic.FileInfo{Name: name})
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if err != nil {
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return err
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}
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}
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return nil
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},
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}
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retryBackend := RetryBackend{
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Backend: be,
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}
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var ErrTest = errors.New("test error")
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var listed []string
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run := 0
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err := retryBackend.List(context.TODO(), restic.DataFile, func(fi restic.FileInfo) error {
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t.Logf("fn called for %v", fi.Name)
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run++
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// return an error for the third item in the list
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if run == 3 {
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t.Log("returning an error")
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return ErrTest
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}
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listed = append(listed, fi.Name)
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return nil
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})
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if err != ErrTest {
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t.Fatalf("wrong error returned, want %v, got %v", ErrTest, err)
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}
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// processing should stop after the error was returned, so run should be 3
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if run != 3 {
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t.Fatalf("function was called %d times, wanted %v", run, 3)
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}
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test.Equals(t, []string{"id1", "id2"}, listed)
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}
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func TestBackendListRetryErrorBackend(t *testing.T) {
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var names = []string{"id1", "id2", "foo", "bar"}
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var ErrBackendTest = errors.New("test error")
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retries := 0
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be := &mock.Backend{
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ListFn: func(ctx context.Context, tpe restic.FileType, fn func(restic.FileInfo) error) error {
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t.Logf("List called for %v, retries %v", tpe, retries)
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retries++
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for i, name := range names {
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if i == 2 {
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return ErrBackendTest
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}
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err := fn(restic.FileInfo{Name: name})
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if err != nil {
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return err
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}
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}
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return nil
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},
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}
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const maxRetries = 2
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retryBackend := RetryBackend{
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MaxTries: maxRetries,
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Backend: be,
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}
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var listed []string
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err := retryBackend.List(context.TODO(), restic.DataFile, func(fi restic.FileInfo) error {
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t.Logf("fn called for %v", fi.Name)
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listed = append(listed, fi.Name)
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return nil
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})
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if err != ErrBackendTest {
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t.Fatalf("wrong error returned, want %v, got %v", ErrBackendTest, err)
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}
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if retries != maxRetries+1 {
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t.Fatalf("List was called %d times, wanted %v", retries, maxRetries+1)
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}
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test.Equals(t, names[:2], listed)
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}
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// failingReader returns an error after reading limit number of bytes
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type failingReader struct {
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data []byte
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pos int
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limit int
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}
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func (r failingReader) Read(p []byte) (n int, err error) {
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i := 0
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for ; i < len(p) && i+r.pos < r.limit; i++ {
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p[i] = r.data[r.pos+i]
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}
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r.pos += i
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if r.pos >= r.limit {
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return i, errors.Errorf("reader reached limit of %d", r.limit)
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}
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return i, nil
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}
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func (r failingReader) Close() error {
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return nil
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}
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// closingReader adapts io.Reader to io.ReadCloser interface
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type closingReader struct {
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rd io.Reader
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}
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func (r closingReader) Read(p []byte) (n int, err error) {
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return r.rd.Read(p)
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}
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func (r closingReader) Close() error {
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return nil
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}
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func TestBackendLoadRetry(t *testing.T) {
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data := test.Random(23, 1024)
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limit := 100
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attempt := 0
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be := mock.NewBackend()
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be.OpenReaderFn = func(ctx context.Context, h restic.Handle, length int, offset int64) (io.ReadCloser, error) {
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// returns failing reader on first invocation, good reader on subsequent invocations
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attempt++
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if attempt > 1 {
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return closingReader{rd: bytes.NewReader(data)}, nil
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}
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return failingReader{data: data, limit: limit}, nil
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}
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retryBackend := RetryBackend{
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Backend: be,
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}
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var buf []byte
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err := retryBackend.Load(context.TODO(), restic.Handle{}, 0, 0, func(rd io.Reader) (err error) {
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buf, err = ioutil.ReadAll(rd)
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return err
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})
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test.OK(t, err)
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test.Equals(t, data, buf)
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test.Equals(t, 2, attempt)
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}
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