cloud drive: add support for Azure

weed/remote_storage/azure/azure_highlevel.go

@@ -0,0 +1,120 @@
+package azure
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"github.com/Azure/azure-pipeline-go/pipeline"
+	. "github.com/Azure/azure-storage-blob-go/azblob"
+	"io"
+	"sync"
+)
+
+// copied from https://github.com/Azure/azure-storage-blob-go/blob/master/azblob/highlevel.go#L73:6
+// uploadReaderAtToBlockBlob was not public
+
+// uploadReaderAtToBlockBlob uploads a buffer in blocks to a block blob.
+func uploadReaderAtToBlockBlob(ctx context.Context, reader io.ReaderAt, readerSize int64,
+	blockBlobURL BlockBlobURL, o UploadToBlockBlobOptions) (CommonResponse, error) {
+	if o.BlockSize == 0 {
+		// If bufferSize > (BlockBlobMaxStageBlockBytes * BlockBlobMaxBlocks), then error
+		if readerSize > BlockBlobMaxStageBlockBytes*BlockBlobMaxBlocks {
+			return nil, errors.New("buffer is too large to upload to a block blob")
+		}
+		// If bufferSize <= BlockBlobMaxUploadBlobBytes, then Upload should be used with just 1 I/O request
+		if readerSize <= BlockBlobMaxUploadBlobBytes {
+			o.BlockSize = BlockBlobMaxUploadBlobBytes // Default if unspecified
+		} else {
+			o.BlockSize = readerSize / BlockBlobMaxBlocks   // buffer / max blocks = block size to use all 50,000 blocks
+			if o.BlockSize < BlobDefaultDownloadBlockSize { // If the block size is smaller than 4MB, round up to 4MB
+				o.BlockSize = BlobDefaultDownloadBlockSize
+			}
+			// StageBlock will be called with blockSize blocks and a Parallelism of (BufferSize / BlockSize).
+		}
+	}
+
+	if readerSize <= BlockBlobMaxUploadBlobBytes {
+		// If the size can fit in 1 Upload call, do it this way
+		var body io.ReadSeeker = io.NewSectionReader(reader, 0, readerSize)
+		if o.Progress != nil {
+			body = pipeline.NewRequestBodyProgress(body, o.Progress)
+		}
+		return blockBlobURL.Upload(ctx, body, o.BlobHTTPHeaders, o.Metadata, o.AccessConditions, o.BlobAccessTier, o.BlobTagsMap, o.ClientProvidedKeyOptions)
+	}
+
+	var numBlocks = uint16(((readerSize - 1) / o.BlockSize) + 1)
+
+	blockIDList := make([]string, numBlocks) // Base-64 encoded block IDs
+	progress := int64(0)
+	progressLock := &sync.Mutex{}
+
+	err := DoBatchTransfer(ctx, BatchTransferOptions{
+		OperationName: "uploadReaderAtToBlockBlob",
+		TransferSize:  readerSize,
+		ChunkSize:     o.BlockSize,
+		Parallelism:   o.Parallelism,
+		Operation: func(offset int64, count int64, ctx context.Context) error {
+			// This function is called once per block.
+			// It is passed this block's offset within the buffer and its count of bytes
+			// Prepare to read the proper block/section of the buffer
+			var body io.ReadSeeker = io.NewSectionReader(reader, offset, count)
+			blockNum := offset / o.BlockSize
+			if o.Progress != nil {
+				blockProgress := int64(0)
+				body = pipeline.NewRequestBodyProgress(body,
+					func(bytesTransferred int64) {
+						diff := bytesTransferred - blockProgress
+						blockProgress = bytesTransferred
+						progressLock.Lock() // 1 goroutine at a time gets a progress report
+						progress += diff
+						o.Progress(progress)
+						progressLock.Unlock()
+					})
+			}
+
+			// Block IDs are unique values to avoid issue if 2+ clients are uploading blocks
+			// at the same time causing PutBlockList to get a mix of blocks from all the clients.
+			blockIDList[blockNum] = base64.StdEncoding.EncodeToString(newUUID().bytes())
+			_, err := blockBlobURL.StageBlock(ctx, blockIDList[blockNum], body, o.AccessConditions.LeaseAccessConditions, nil, o.ClientProvidedKeyOptions)
+			return err
+		},
+	})
+	if err != nil {
+		return nil, err
+	}
+	// All put blocks were successful, call Put Block List to finalize the blob
+	return blockBlobURL.CommitBlockList(ctx, blockIDList, o.BlobHTTPHeaders, o.Metadata, o.AccessConditions, o.BlobAccessTier, o.BlobTagsMap, o.ClientProvidedKeyOptions)
+}
+
+// The UUID reserved variants.
+const (
+	reservedNCS       byte = 0x80
+	reservedRFC4122   byte = 0x40
+	reservedMicrosoft byte = 0x20
+	reservedFuture    byte = 0x00
+)
+
+type uuid [16]byte
+
+// NewUUID returns a new uuid using RFC 4122 algorithm.
+func newUUID() (u uuid) {
+	u = uuid{}
+	// Set all bits to randomly (or pseudo-randomly) chosen values.
+	rand.Read(u[:])
+	u[8] = (u[8] | reservedRFC4122) & 0x7F // u.setVariant(ReservedRFC4122)
+
+	var version byte = 4
+	u[6] = (u[6] & 0xF) | (version << 4) // u.setVersion(4)
+	return
+}
+
+// String returns an unparsed version of the generated UUID sequence.
+func (u uuid) String() string {
+	return fmt.Sprintf("%x-%x-%x-%x-%x", u[0:4], u[4:6], u[6:8], u[8:10], u[10:])
+}
+
+func (u uuid) bytes() []byte {
+	return u[:]
+}