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Implements zero fill behaviour for large offset in WriteStream

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This requires a very intricate WriteStream test, which will be in the next commit.
This commit is contained in:
Andrey Kostov 2014-12-19 19:20:07 +02:00
parent 8ca960a0b5
commit 11ed0515d0
2 changed files with 225 additions and 43 deletions
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234
storagedriver/s3/s3.go
View file

@ -192,6 +192,7 @@ func (d *Driver) WriteStream(path string, offset int64, reader io.Reader) (total
}
partNumber := 1
bytesRead := 0
parts := []s3.Part{}
var part s3.Part
@ -201,6 +202,7 @@ func (d *Driver) WriteStream(path string, offset int64, reader io.Reader) (total
}
buf := make([]byte, chunkSize)
zeroBuf := make([]byte, chunkSize)
// We never want to leave a dangling multipart upload, our only consistent state is
// when there is a whole object at path. This is in order to remain consistent with
@ -211,54 +213,86 @@ func (d *Driver) WriteStream(path string, offset int64, reader io.Reader) (total
// made prior to the machine crashing.
defer func() {
if len(parts) > 0 {
err = multi.Complete(parts)
if err != nil {
if multi == nil {
// Parts should be empty if the multi is not initialized
panic("Unreachable")
} else {
if multi.Complete(parts) != nil {
multi.Abort()
}
}
}
}()
// Fills from 0 to total from current
fromSmallCurrent := func(total int64) error {
current, err := d.ReadStream(path, 0)
if err != nil {
return err
}
bytesRead = 0
for int64(bytesRead) < total {
//The loop should very rarely enter a second iteration
nn, err := io.ReadFull(current, buf[bytesRead:total])
if err != nil && err != io.ErrUnexpectedEOF && err != io.EOF {
return err
}
bytesRead += nn
}
return nil
}
// Fills from parameter to chunkSize from reader
fromReader := func(from int64) error {
bytesRead = 0
for int64(bytesRead) < chunkSize {
nn, err := io.ReadFull(reader, buf[from+int64(bytesRead):])
totalRead += int64(nn)
bytesRead += nn
if err != nil && err != io.ErrUnexpectedEOF && err != io.EOF {
return err
}
}
part, err = multi.PutPart(int(partNumber), bytes.NewReader(buf[0:int64(bytesRead)+from]))
if err != nil {
return err
}
return nil
}
if offset > 0 {
resp, err := d.Bucket.Head(d.s3Path(path), nil)
if err != nil {
if s3Err, ok := err.(*s3.Error); !ok || s3Err.Code != "NoSuchKey" {
return 0, err
}
if resp.ContentLength < offset {
return 0, storagedriver.InvalidOffsetError{Path: path, Offset: offset}
}
if resp.ContentLength < chunkSize {
// If everything written so far is less than the minimum part size of 5MB, we need
// to fill out the first part up to that minimum.
current, err := d.ReadStream(path, 0)
if err != nil {
return 0, err
currentLength := int64(0)
if err == nil {
currentLength = resp.ContentLength
}
bytesRead, err := io.ReadFull(current, buf[0:offset])
if err != nil && err != io.ErrUnexpectedEOF && err != io.EOF {
return 0, err
} else if int64(bytesRead) != offset {
//TODO Maybe a different error? I don't even think this case is reachable...
return 0, storagedriver.InvalidOffsetError{Path: path, Offset: offset}
}
bytesRead, err = io.ReadFull(reader, buf[offset:])
totalRead += int64(bytesRead)
if err != nil && err != io.ErrUnexpectedEOF && err != io.EOF {
if currentLength >= offset {
if offset < chunkSize {
// chunkSize > currentLength >= offset
if err = fromSmallCurrent(offset); err != nil {
return totalRead, err
}
part, err = multi.PutPart(int(partNumber), bytes.NewReader(buf[0:int64(bytesRead)+offset]))
if err != nil {
if err = fromReader(offset); err != nil {
return totalRead, err
}
} else {
fmt.Println("About to PutPartCopy")
// If the file that we already have is larger than 5MB, then we make it the first part
// of the new multipart upload.
_, part, err = multi.PutPartCopy(partNumber, s3.CopyOptions{}, d.Bucket.Name+"/"+d.s3Path(path))
// currentLength >= offset >= chunkSize
_, part, err = multi.PutPartCopy(partNumber,
s3.CopyOptions{CopySourceOptions: "bytes=0-" + strconv.FormatInt(offset-1, 10)},
d.Bucket.Name+"/"+d.s3Path(path))
if err != nil {
return 0, err
}
@ -270,6 +304,150 @@ func (d *Driver) WriteStream(path string, offset int64, reader io.Reader) (total
if totalRead+offset < chunkSize {
return totalRead, nil
}
} else {
// Fills between parameters with 0s but only when to - from <= chunkSize
fromZeroFillSmall := func(from, to int64) error {
bytesRead = 0
for from+int64(bytesRead) < to {
nn, err := io.ReadFull(bytes.NewReader(zeroBuf), buf[from+int64(bytesRead):to])
bytesRead += nn
if err != nil && err != io.ErrUnexpectedEOF && err != io.EOF {
return err
}
}
return nil
}
// Fills between parameters with 0s, making new parts
fromZeroFillLarge := func(from, to int64) error {
bytesRead64 := int64(0)
for to-(from+bytesRead64) >= chunkSize {
part, err := multi.PutPart(int(partNumber), bytes.NewReader(zeroBuf))
if err != nil {
return err
}
bytesRead64 += chunkSize
parts = append(parts, part)
partNumber++
}
bytesRead = 0
for from+bytesRead64+int64(bytesRead) < to {
nn, err := io.ReadFull(bytes.NewReader(zeroBuf), buf[0+bytesRead:(to-from)%chunkSize])
bytesRead64 += int64(nn)
if err != nil && err != io.ErrUnexpectedEOF && err != io.EOF {
return err
}
}
return nil
}
// currentLength < offset
if currentLength < chunkSize {
if offset < chunkSize {
// chunkSize > offset > currentLength
if err = fromSmallCurrent(currentLength); err != nil {
return totalRead, err
}
if err = fromZeroFillSmall(currentLength, offset); err != nil {
return totalRead, err
}
if err = fromReader(offset); err != nil {
return totalRead, err
}
part, err = multi.PutPart(int(partNumber), bytes.NewReader(buf))
if err != nil {
return totalRead, err
}
parts = append(parts, part)
partNumber++
if totalRead+offset < chunkSize {
return totalRead, nil
}
} else {
// offset >= chunkSize > currentLength
if err = fromSmallCurrent(currentLength); err != nil {
return totalRead, err
}
if err = fromZeroFillSmall(currentLength, chunkSize); err != nil {
return totalRead, err
}
part, err = multi.PutPart(int(partNumber), bytes.NewReader(buf))
if err != nil {
return totalRead, err
}
parts = append(parts, part)
partNumber++
//Zero fill from chunkSize up to offset, then some reader
if err = fromZeroFillLarge(chunkSize, offset); err != nil {
return totalRead, err
}
if err = fromReader(offset % chunkSize); err != nil {
return totalRead, err
}
part, err = multi.PutPart(int(partNumber), bytes.NewReader(buf))
if err != nil {
return totalRead, err
}
parts = append(parts, part)
partNumber++
if totalRead+(offset%chunkSize) < chunkSize {
return totalRead, nil
}
}
} else {
// offset > currentLength >= chunkSize
_, part, err = multi.PutPartCopy(partNumber,
s3.CopyOptions{CopySourceOptions: "bytes=0-" + strconv.FormatInt(currentLength-1, 10)},
d.Bucket.Name+"/"+d.s3Path(path))
if err != nil {
return 0, err
}
parts = append(parts, part)
partNumber++
//Zero fill from currentLength up to offset, then some reader
if err = fromZeroFillLarge(currentLength, offset); err != nil {
return totalRead, err
}
if err = fromReader((offset - currentLength) % chunkSize); err != nil {
return totalRead, err
}
part, err = multi.PutPart(int(partNumber), bytes.NewReader(buf))
if err != nil {
return totalRead, err
}
parts = append(parts, part)
partNumber++
if totalRead+((offset-currentLength)%chunkSize) < chunkSize {
return totalRead, nil
}
}
}
}
for {

6
storagedriver/testsuites/testsuites.go
View file

@ -916,9 +916,13 @@ func (suite *DriverSuite) testFileStreams(c *check.C, size int64) {
tf.Sync()
tf.Seek(0, os.SEEK_SET)
totalRead := int64(0)
for totalRead < size {
nn, err := suite.StorageDriver.WriteStream(filename, 0, tf)
c.Assert(err, check.IsNil)
c.Assert(nn, check.Equals, size)
totalRead += nn
}
c.Assert(totalRead, check.Equals, size)
reader, err := suite.StorageDriver.ReadStream(filename, 0)
c.Assert(err, check.IsNil)