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// Copyright 2013 Canonical Ltd. This software is licensed under the
// GNU Lesser General Public License version 3 (see the file COPYING).
package gwacl
// This file contains higher level operations necessary to work with the Azure
// file storage API.
import (
"bytes"
"encoding/base64"
"fmt"
"io"
. "launchpad.net/gwacl/logging"
"strconv"
"strings"
)
// UploadBlockBlob uses PutBlock and PutBlockList API operations to upload
// arbitrarily large files, 1MB at a time.
func (context *StorageContext) UploadBlockBlob(
container, filename string, data io.Reader) error {
buffer := make([]byte, 1024*1024) // 1MB buffer
blockList := &BlockList{}
// Upload the file in chunks.
for blockNum := int64(0); ; blockNum++ {
blockSize, err := data.Read(buffer)
if err == io.EOF {
break
}
if err != nil {
return err
}
block := bytes.NewReader(buffer[:blockSize])
blockID := strconv.FormatInt(blockNum, 36)
Debugf("Uploading block %d (size=%d, id=%s).\n",
blockNum, blockSize, blockID)
err = context.PutBlock(container, filename, blockID, block)
if err != nil {
return err
}
blockList.Add(BlockListLatest, blockID)
}
// Commit those blocks by writing the block list.
Debugf("Committing %d blocks.\n", len(blockList.Items))
return context.PutBlockList(container, filename, blockList)
}
// ListAllBlobs requests from the API a list of blobs in a container.
func (context *StorageContext) ListAllBlobs(request *ListBlobsRequest) (*BlobEnumerationResults, error) {
blobs := make([]Blob, 0)
var batch *BlobEnumerationResults
// Request the initial result, using the empty marker. Then, for as long
// as the result has a nonempty NextMarker, request the next batch using
// that marker.
// This loop is very similar to the one in ListAllContainers().
for marker, nextMarker := "", "x"; nextMarker != ""; marker = nextMarker {
var err error
// Don't use := here or you'll shadow variables from the function's
// outer scopes.
request.Marker = marker
batch, err = context.ListBlobs(request)
if err != nil {
return nil, err
}
// The response may contain a NextMarker field, to let us request a
// subsequent batch of results. The XML parser won't trim whitespace out
// of the marker tag, so we do that here.
nextMarker = strings.TrimSpace(batch.NextMarker)
blobs = append(blobs, batch.Blobs...)
}
// There's more in a BlobsEnumerationResults than just the blobs.
// Return the latest batch, but give it the full cumulative blobs list
// instead of just the last batch.
// To the caller, this will look like they made one call to Azure's
// List Blobs method, but batch size was unlimited.
batch.Blobs = blobs
return batch, nil
}
type DeleteAllBlobsRequest struct {
Container string
// Other params possible, add later.
}
// RemoveAllBlobs requests a deletion of all the blobs in a container.
// The blobs are not deleted immediately, so when this call returns they
// may still be present for a while.
func (context *StorageContext) DeleteAllBlobs(request *DeleteAllBlobsRequest) error {
blobs, err := context.ListAllBlobs(&ListBlobsRequest{
Container: request.Container})
if err != nil {
return err
}
for _, blob := range blobs.Blobs {
err := context.DeleteBlob(request.Container, blob.Name)
if err != nil {
return err
}
}
return nil
}
// ListAllContainers requests from the storage service a list of containers
// in the storage account.
func (context *StorageContext) ListAllContainers() (*ContainerEnumerationResults, error) {
containers := make([]Container, 0)
var batch *ContainerEnumerationResults
// Request the initial result, using the empty marker. Then, for as long
// as the result has a nonempty NextMarker, request the next batch using
// that marker.
for marker, nextMarker := "", "x"; nextMarker != ""; marker = nextMarker {
var err error
// Don't use := here or you'll shadow variables from the function's
// outer scopes.
request := &ListContainersRequest{Marker: marker}
batch, err = context.ListContainers(request)
if err != nil {
return nil, err
}
// The response may contain a NextMarker field, to let us request a
// subsequent batch of results. The XML parser won't trim whitespace out
// of the marker tag, so we do that here.
nextMarker = strings.TrimSpace(batch.NextMarker)
containers = append(containers, batch.Containers...)
}
// There's more in a ContainerEnumerationResults than just the containers.
// Return the latest batch, but give it the full cumulative containers list
// instead of just the last batch.
// To the caller, this will look like they made one call to Azure's
// List Containers method, but batch size was unlimited.
batch.Containers = containers
return batch, nil
}
type CreateVHDRequest struct {
Container string // Container name in the storage account
Filename string // Specify the filename in which to store the VHD
FilesystemData io.Reader // A formatted filesystem, e.g. iso9660.
Size int // How many bytes from the Filesystem data to upload. *Must* be a multiple of 512.
}
// CreateInstanceDataVHD will take the supplied filesystem data and create an
// Azure VHD in a page blob out of it. The data cannot be bigger than
// gwacl.VHD_SIZE-512. This is intended to be used as a way of passing
// arbitrary data to a new instance - create a disk here and then attach it to
// the new instance.
func (context *StorageContext) CreateInstanceDataVHD(req *CreateVHDRequest) error {
// We need several steps:
// 1. Create an empty page blob of exactly VHD_SIZE bytes (see
// vhd_footer.go)
// 2. Upload VHD_FOOTER to the last page of the blob.
// 3. Upload the supplied FilesystemData from the start of the blob.
var err error
if req.Size%512 != 0 {
return fmt.Errorf("Size must be a multiple of 512")
}
if req.Size > VHD_SIZE-512 {
// Protect against writing over the VHD footer.
return fmt.Errorf("Size cannot be bigger than %d", VHD_SIZE-512)
}
// Step 1.
err = context.PutBlob(&PutBlobRequest{
Container: req.Container,
BlobType: "page",
Filename: req.Filename,
Size: VHD_SIZE,
})
if err != nil {
return err
}
// Step 2.
data, err := base64.StdEncoding.DecodeString(VHD_FOOTER)
if err != nil {
// This really shouldn't ever happen since there's a test to make sure
// it can be decoded.
panic(err)
}
dataReader := bytes.NewReader(data)
err = context.PutPage(&PutPageRequest{
Container: req.Container,
Filename: req.Filename,
StartRange: VHD_SIZE - 512, // last page of the blob
EndRange: VHD_SIZE - 1,
Data: dataReader,
})
if err != nil {
return err
}
// Step 3.
err = context.PutPage(&PutPageRequest{
Container: req.Container,
Filename: req.Filename,
StartRange: 0,
EndRange: req.Size - 1,
Data: req.FilesystemData,
})
if err != nil {
return err
}
return nil
}
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