func TestRetriableReaderReturnsEOFs(t *testing.T) {
r := tools.NewRetriableReader(bytes.NewBuffer([]byte{ /* empty */ }))
var buf [1]byte
n, err := r.Read(buf[:])
assert.Equal(t, io.EOF, err)
assert.Equal(t, 0, n)
}
func TestRetriableReaderReturnsSuccessfulReads(t *testing.T) {
r := tools.NewRetriableReader(bytes.NewBuffer([]byte{0x1, 0x2, 0x3, 0x4}))
var buf [4]byte
n, err := r.Read(buf[:])
assert.Nil(t, err)
assert.Equal(t, 4, n)
assert.Equal(t, []byte{0x1, 0x2, 0x3, 0x4}, buf[:])
}
func TestRetriableReaderMakesErrorsRetriable(t *testing.T) {
expected := errors.New("example error")
r := tools.NewRetriableReader(&ErrReader{expected})
var buf [1]byte
n, err := r.Read(buf[:])
assert.Equal(t, 0, n)
assert.EqualError(t, err, "LFS: "+expected.Error())
assert.True(t, errors.IsRetriableError(err))
}
func TestRetriableReaderDoesNotRewrap(t *testing.T) {
// expected is already "retriable", as would be the case if the
// underlying reader was a *RetriableReader itself.
expected := errors.NewRetriableError(errors.New("example error"))
r := tools.NewRetriableReader(&ErrReader{expected})
var buf [1]byte
n, err := r.Read(buf[:])
assert.Equal(t, 0, n)
// errors.NewRetriableError wraps the given error with the prefix
// message "LFS", so these two errors should be equal, indicating that
// the RetriableReader did not re-wrap the error it received.
assert.EqualError(t, err, expected.Error())
assert.True(t, errors.IsRetriableError(err))
}
// download starts or resumes and download. Always closes dlFile if non-nil
func (a *basicDownloadAdapter) download(t *Transfer, cb TransferProgressCallback, authOkFunc func(), dlFile *os.File, fromByte int64, hash hash.Hash) error {
if dlFile != nil {
// ensure we always close dlFile. Note that this does not conflict with the
// early close below, as close is idempotent.
defer dlFile.Close()
}
rel, ok := t.Object.Rel("download")
if !ok {
return errors.New("Object not found on the server.")
}
req, err := httputil.NewHttpRequest("GET", rel.Href, rel.Header)
if err != nil {
return err
}
if fromByte > 0 {
if dlFile == nil || hash == nil {
return fmt.Errorf("Cannot restart %v from %d without a file & hash", t.Object.Oid, fromByte)
}
// We could just use a start byte, but since we know the length be specific
req.Header.Set("Range", fmt.Sprintf("bytes=%d-%d", fromByte, t.Object.Size-1))
}
res, err := httputil.DoHttpRequest(config.Config, req, t.Object.NeedsAuth())
if err != nil {
// Special-case status code 416 () - fall back
if fromByte > 0 && dlFile != nil && res.StatusCode == 416 {
tracerx.Printf("xfer: server rejected resume download request for %q from byte %d; re-downloading from start", t.Object.Oid, fromByte)
dlFile.Close()
os.Remove(dlFile.Name())
return a.download(t, cb, authOkFunc, nil, 0, nil)
}
return errors.NewRetriableError(err)
}
httputil.LogTransfer(config.Config, "lfs.data.download", res)
defer res.Body.Close()
// Range request must return 206 & content range to confirm
if fromByte > 0 {
rangeRequestOk := false
var failReason string
// check 206 and Content-Range, fall back if either not as expected
if res.StatusCode == 206 {
// Probably a successful range request, check Content-Range
if rangeHdr := res.Header.Get("Content-Range"); rangeHdr != "" {
regex := regexp.MustCompile(`bytes (\d+)\-.*`)
match := regex.FindStringSubmatch(rangeHdr)
if match != nil && len(match) > 1 {
contentStart, _ := strconv.ParseInt(match[1], 10, 64)
if contentStart == fromByte {
rangeRequestOk = true
} else {
failReason = fmt.Sprintf("Content-Range start byte incorrect: %s expected %d", match[1], fromByte)
}
} else {
failReason = fmt.Sprintf("badly formatted Content-Range header: %q", rangeHdr)
}
} else {
failReason = "missing Content-Range header in response"
}
} else {
failReason = fmt.Sprintf("expected status code 206, received %d", res.StatusCode)
}
if rangeRequestOk {
tracerx.Printf("xfer: server accepted resume download request: %q from byte %d", t.Object.Oid, fromByte)
advanceCallbackProgress(cb, t, fromByte)
} else {
// Abort resume, perform regular download
tracerx.Printf("xfer: failed to resume download for %q from byte %d: %s. Re-downloading from start", t.Object.Oid, fromByte, failReason)
dlFile.Close()
os.Remove(dlFile.Name())
if res.StatusCode == 200 {
// If status code was 200 then server just ignored Range header and
// sent everything. Don't re-request, use this one from byte 0
dlFile = nil
fromByte = 0
hash = nil
} else {
// re-request needed
return a.download(t, cb, authOkFunc, nil, 0, nil)
}
}
}
// Signal auth OK on success response, before starting download to free up
// other workers immediately
if authOkFunc != nil {
authOkFunc()
}
var hasher *tools.HashingReader
httpReader := tools.NewRetriableReader(res.Body)
if fromByte > 0 && hash != nil {
// pre-load hashing reader with previous content
hasher = tools.NewHashingReaderPreloadHash(httpReader, hash)
} else {
hasher = tools.NewHashingReader(httpReader)
}
if dlFile == nil {
// New file start
dlFile, err = os.OpenFile(a.downloadFilename(t), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
return err
}
defer dlFile.Close()
}
dlfilename := dlFile.Name()
// Wrap callback to give name context
ccb := func(totalSize int64, readSoFar int64, readSinceLast int) error {
if cb != nil {
return cb(t.Name, totalSize, readSoFar+fromByte, readSinceLast)
}
return nil
}
written, err := tools.CopyWithCallback(dlFile, hasher, res.ContentLength, ccb)
if err != nil {
return errors.Wrapf(err, "cannot write data to tempfile %q", dlfilename)
}
if err := dlFile.Close(); err != nil {
return fmt.Errorf("can't close tempfile %q: %v", dlfilename, err)
}
if actual := hasher.Hash(); actual != t.Object.Oid {
return fmt.Errorf("Expected OID %s, got %s after %d bytes written", t.Object.Oid, actual, written)
}
return tools.RenameFileCopyPermissions(dlfilename, t.Path)
}
