17 "github.com/curoverse/azure-sdk-for-go/storage"
22 azureStorageAccountName string
23 azureStorageAccountKeyFile string
24 azureStorageReplication int
25 azureWriteRaceInterval = 15 * time.Second
26 azureWriteRacePollTime = time.Second
29 func readKeyFromFile(file string) (string, error) {
30 buf, err := ioutil.ReadFile(file)
32 return "", errors.New("reading key from " + file + ": " + err.Error())
34 accountKey := strings.TrimSpace(string(buf))
36 return "", errors.New("empty account key in " + file)
38 return accountKey, nil
41 type azureVolumeAdder struct {
45 func (s *azureVolumeAdder) Set(containerName string) error {
46 if trashLifetime <= 0 {
47 log.Print("Missing required configuration parameter: trash-lifetime")
48 return ErrNotImplemented
51 if containerName == "" {
52 return errors.New("no container name given")
54 if azureStorageAccountName == "" || azureStorageAccountKeyFile == "" {
55 return errors.New("-azure-storage-account-name and -azure-storage-account-key-file arguments must given before -azure-storage-container-volume")
57 accountKey, err := readKeyFromFile(azureStorageAccountKeyFile)
61 azClient, err := storage.NewBasicClient(azureStorageAccountName, accountKey)
63 return errors.New("creating Azure storage client: " + err.Error())
66 log.Print("Notice: -serialize is not supported by azure-blob-container volumes.")
68 v := NewAzureBlobVolume(azClient, containerName, flagReadonly, azureStorageReplication)
69 if err := v.Check(); err != nil {
72 *s.volumeSet = append(*s.volumeSet, v)
77 flag.Var(&azureVolumeAdder{&volumes},
78 "azure-storage-container-volume",
79 "Use the given container as a storage volume. Can be given multiple times.")
81 &azureStorageAccountName,
82 "azure-storage-account-name",
84 "Azure storage account name used for subsequent --azure-storage-container-volume arguments.")
86 &azureStorageAccountKeyFile,
87 "azure-storage-account-key-file",
89 "File containing the account key used for subsequent --azure-storage-container-volume arguments.")
91 &azureStorageReplication,
92 "azure-storage-replication",
94 "Replication level to report to clients when data is stored in an Azure container.")
97 "azure-max-get-bytes",
99 fmt.Sprintf("Maximum bytes to request in a single GET request. If smaller than %d, use multiple concurrent range requests to retrieve a block.", BlockSize))
102 // An AzureBlobVolume stores and retrieves blocks in an Azure Blob
104 type AzureBlobVolume struct {
105 azClient storage.Client
106 bsClient storage.BlobStorageClient
112 // NewAzureBlobVolume returns a new AzureBlobVolume using the given
113 // client and container name. The replication argument specifies the
114 // replication level to report when writing data.
115 func NewAzureBlobVolume(client storage.Client, containerName string, readonly bool, replication int) *AzureBlobVolume {
116 return &AzureBlobVolume{
118 bsClient: client.GetBlobService(),
119 containerName: containerName,
121 replication: replication,
125 // Check returns nil if the volume is usable.
126 func (v *AzureBlobVolume) Check() error {
127 ok, err := v.bsClient.ContainerExists(v.containerName)
132 return errors.New("container does not exist")
137 // Get reads a Keep block that has been stored as a block blob in the
140 // If the block is younger than azureWriteRaceInterval and is
141 // unexpectedly empty, assume a PutBlob operation is in progress, and
142 // wait for it to finish writing.
143 func (v *AzureBlobVolume) Get(loc string) ([]byte, error) {
144 var deadline time.Time
145 haveDeadline := false
146 buf, err := v.get(loc)
147 for err == nil && len(buf) == 0 && loc != "d41d8cd98f00b204e9800998ecf8427e" {
148 // Seeing a brand new empty block probably means we're
149 // in a race with CreateBlob, which under the hood
150 // (apparently) does "CreateEmpty" and "CommitData"
151 // with no additional transaction locking.
153 t, err := v.Mtime(loc)
155 log.Print("Got empty block (possible race) but Mtime failed: ", err)
158 deadline = t.Add(azureWriteRaceInterval)
159 if time.Now().After(deadline) {
162 log.Printf("Race? Block %s is 0 bytes, %s old. Polling until %s", loc, time.Since(t), deadline)
164 } else if time.Now().After(deadline) {
168 time.Sleep(azureWriteRacePollTime)
169 buf, err = v.get(loc)
172 log.Printf("Race ended with len(buf)==%d", len(buf))
177 func (v *AzureBlobVolume) get(loc string) ([]byte, error) {
178 expectSize := BlockSize
179 if azureMaxGetBytes < BlockSize {
180 // Unfortunately the handler doesn't tell us how long the blob
181 // is expected to be, so we have to ask Azure.
182 props, err := v.bsClient.GetBlobProperties(v.containerName, loc)
184 return nil, v.translateError(err)
186 if props.ContentLength > int64(BlockSize) || props.ContentLength < 0 {
187 return nil, fmt.Errorf("block %s invalid size %d (max %d)", loc, props.ContentLength, BlockSize)
189 expectSize = int(props.ContentLength)
192 buf := bufs.Get(expectSize)
197 // We'll update this actualSize if/when we get the last piece.
199 pieces := (expectSize + azureMaxGetBytes - 1) / azureMaxGetBytes
200 errors := make([]error, pieces)
201 var wg sync.WaitGroup
203 for p := 0; p < pieces; p++ {
206 startPos := p * azureMaxGetBytes
207 endPos := startPos + azureMaxGetBytes
208 if endPos > expectSize {
211 var rdr io.ReadCloser
213 if startPos == 0 && endPos == expectSize {
214 rdr, err = v.bsClient.GetBlob(v.containerName, loc)
216 rdr, err = v.bsClient.GetBlobRange(v.containerName, loc, fmt.Sprintf("%d-%d", startPos, endPos-1))
223 n, err := io.ReadFull(rdr, buf[startPos:endPos])
224 if pieces == 1 && (err == io.ErrUnexpectedEOF || err == io.EOF) {
225 // If we don't know the actual size,
226 // and just tried reading 64 MiB, it's
227 // normal to encounter EOF.
228 } else if err != nil {
232 actualSize = startPos + n
237 for _, err := range errors {
240 return nil, v.translateError(err)
243 return buf[:actualSize], nil
246 // Compare the given data with existing stored data.
247 func (v *AzureBlobVolume) Compare(loc string, expect []byte) error {
248 rdr, err := v.bsClient.GetBlob(v.containerName, loc)
250 return v.translateError(err)
253 return compareReaderWithBuf(rdr, expect, loc[:32])
256 // Put stores a Keep block as a block blob in the container.
257 func (v *AzureBlobVolume) Put(loc string, block []byte) error {
259 return MethodDisabledError
261 return v.bsClient.CreateBlockBlobFromReader(v.containerName, loc, uint64(len(block)), bytes.NewReader(block))
264 // Touch updates the last-modified property of a block blob.
265 func (v *AzureBlobVolume) Touch(loc string) error {
267 return MethodDisabledError
269 return v.bsClient.SetBlobMetadata(v.containerName, loc, map[string]string{
270 "touch": fmt.Sprintf("%d", time.Now()),
274 // Mtime returns the last-modified property of a block blob.
275 func (v *AzureBlobVolume) Mtime(loc string) (time.Time, error) {
276 props, err := v.bsClient.GetBlobProperties(v.containerName, loc)
278 return time.Time{}, err
280 return time.Parse(time.RFC1123, props.LastModified)
283 // IndexTo writes a list of Keep blocks that are stored in the
285 func (v *AzureBlobVolume) IndexTo(prefix string, writer io.Writer) error {
286 params := storage.ListBlobsParameters{
290 resp, err := v.bsClient.ListBlobs(v.containerName, params)
294 for _, b := range resp.Blobs {
295 t, err := time.Parse(time.RFC1123, b.Properties.LastModified)
299 if !v.isKeepBlock(b.Name) {
302 if b.Properties.ContentLength == 0 && t.Add(azureWriteRaceInterval).After(time.Now()) {
303 // A new zero-length blob is probably
304 // just a new non-empty blob that
305 // hasn't committed its data yet (see
306 // Get()), and in any case has no
310 fmt.Fprintf(writer, "%s+%d %d\n", b.Name, b.Properties.ContentLength, t.Unix())
312 if resp.NextMarker == "" {
315 params.Marker = resp.NextMarker
319 // Trash a Keep block.
320 func (v *AzureBlobVolume) Trash(loc string) error {
322 return MethodDisabledError
324 // Ideally we would use If-Unmodified-Since, but that
325 // particular condition seems to be ignored by Azure. Instead,
326 // we get the Etag before checking Mtime, and use If-Match to
327 // ensure we don't delete data if Put() or Touch() happens
328 // between our calls to Mtime() and DeleteBlob().
329 props, err := v.bsClient.GetBlobProperties(v.containerName, loc)
333 if t, err := v.Mtime(loc); err != nil {
335 } else if time.Since(t) < blobSignatureTTL {
338 return v.bsClient.DeleteBlob(v.containerName, loc, map[string]string{
339 "If-Match": props.Etag,
343 // Untrash a Keep block.
345 func (v *AzureBlobVolume) Untrash(loc string) error {
349 // Status returns a VolumeStatus struct with placeholder data.
350 func (v *AzureBlobVolume) Status() *VolumeStatus {
351 return &VolumeStatus{
353 BytesFree: BlockSize * 1000,
358 // String returns a volume label, including the container name.
359 func (v *AzureBlobVolume) String() string {
360 return fmt.Sprintf("azure-storage-container:%+q", v.containerName)
363 // Writable returns true, unless the -readonly flag was on when the
365 func (v *AzureBlobVolume) Writable() bool {
369 // Replication returns the replication level of the container, as
370 // specified by the -azure-storage-replication argument.
371 func (v *AzureBlobVolume) Replication() int {
375 // If possible, translate an Azure SDK error to a recognizable error
376 // like os.ErrNotExist.
377 func (v *AzureBlobVolume) translateError(err error) error {
381 case strings.Contains(err.Error(), "404 Not Found"):
382 // "storage: service returned without a response body (404 Not Found)"
383 return os.ErrNotExist
389 var keepBlockRegexp = regexp.MustCompile(`^[0-9a-f]{32}$`)
391 func (v *AzureBlobVolume) isKeepBlock(s string) bool {
392 return keepBlockRegexp.MatchString(s)