16 "github.com/AdRoll/goamz/aws"
17 "github.com/AdRoll/goamz/s3"
21 ErrS3TrashNotAvailable = fmt.Errorf("trash is not possible because -trash-lifetime=0 and -s3-unsafe-delete=false")
23 s3AccessKeyFile string
24 s3SecretKeyFile string
29 s3RaceWindow time.Duration
35 maxClockSkew = 600 * time.Second
36 nearlyRFC1123 = "Mon, 2 Jan 2006 15:04:05 GMT"
39 type s3VolumeAdder struct {
43 func (s *s3VolumeAdder) Set(bucketName string) error {
44 if trashLifetime != 0 {
45 return ErrNotImplemented
48 return fmt.Errorf("no container name given")
50 if s3AccessKeyFile == "" || s3SecretKeyFile == "" {
51 return fmt.Errorf("-s3-access-key-file and -s3-secret-key-file arguments must given before -s3-bucket-volume")
53 region, ok := aws.Regions[s3RegionName]
56 return fmt.Errorf("unrecognized region %+q; try specifying -s3-endpoint instead", s3RegionName)
60 return fmt.Errorf("refusing to use AWS region name %+q with endpoint %+q; "+
61 "specify empty endpoint (\"-s3-endpoint=\") or use a different region name", s3RegionName, s3Endpoint)
65 S3Endpoint: s3Endpoint,
70 auth.AccessKey, err = readKeyFromFile(s3AccessKeyFile)
74 auth.SecretKey, err = readKeyFromFile(s3SecretKeyFile)
79 log.Print("Notice: -serialize is not supported by s3-bucket volumes.")
81 v := NewS3Volume(auth, region, bucketName, s3RaceWindow, flagReadonly, s3Replication)
82 if err := v.Check(); err != nil {
85 *s.volumeSet = append(*s.volumeSet, v)
89 func s3regions() (okList []string) {
90 for r := range aws.Regions {
91 okList = append(okList, r)
97 flag.Var(&s3VolumeAdder{&volumes},
99 "Use the given bucket as a storage volume. Can be given multiple times.")
104 fmt.Sprintf("AWS region used for subsequent -s3-bucket-volume arguments. Allowed values are %+q.", s3regions()))
109 "Endpoint URL used for subsequent -s3-bucket-volume arguments. If blank, use the AWS endpoint corresponding to the -s3-region argument. For Google Storage, use \"https://storage.googleapis.com\".")
112 "s3-access-key-file",
114 "File containing the access key used for subsequent -s3-bucket-volume arguments.")
117 "s3-secret-key-file",
119 "File containing the secret key used for subsequent -s3-bucket-volume arguments.")
124 "Maximum eventual consistency latency for subsequent -s3-bucket-volume arguments.")
129 "Replication level reported to clients for subsequent -s3-bucket-volume arguments.")
134 "EXPERIMENTAL. Enable deletion (garbage collection), even though there are known race conditions that can cause data loss.")
137 type S3Volume struct {
139 raceWindow time.Duration
145 // NewS3Volume returns a new S3Volume using the given auth, region,
146 // and bucket name. The replication argument specifies the replication
147 // level to report when writing data.
148 func NewS3Volume(auth aws.Auth, region aws.Region, bucket string, raceWindow time.Duration, readonly bool, replication int) *S3Volume {
151 S3: s3.New(auth, region),
154 raceWindow: raceWindow,
156 replication: replication,
161 func (v *S3Volume) Check() error {
165 func (v *S3Volume) getReaderWithFixRace(loc string) (rdr io.ReadCloser, err error) {
166 rdr, err = v.Bucket.GetReader(loc)
167 err = v.translateError(err)
168 if err == nil || !os.IsNotExist(err) {
171 _, err = v.Bucket.Head("recent/"+loc, nil)
172 err = v.translateError(err)
174 // If we can't read recent/X, there's no point in
175 // trying fixRace. Give up.
182 rdr, err = v.Bucket.GetReader(loc)
184 log.Printf("warning: reading %s after successful fixRace: %s", loc, err)
185 err = v.translateError(err)
190 func (v *S3Volume) Get(loc string, buf []byte) (int, error) {
191 rdr, err := v.getReaderWithFixRace(loc)
196 n, err := io.ReadFull(rdr, buf)
198 case nil, io.EOF, io.ErrUnexpectedEOF:
201 return 0, v.translateError(err)
205 func (v *S3Volume) Compare(loc string, expect []byte) error {
206 rdr, err := v.getReaderWithFixRace(loc)
211 return v.translateError(compareReaderWithBuf(rdr, expect, loc[:32]))
214 func (v *S3Volume) Put(loc string, block []byte) error {
216 return MethodDisabledError
220 md5, err := hex.DecodeString(loc)
224 opts.ContentMD5 = base64.StdEncoding.EncodeToString(md5)
226 err := v.Bucket.Put(loc, block, "application/octet-stream", s3ACL, opts)
228 return v.translateError(err)
230 err = v.Bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{})
231 return v.translateError(err)
234 func (v *S3Volume) Touch(loc string) error {
236 return MethodDisabledError
238 _, err := v.Bucket.Head(loc, nil)
239 err = v.translateError(err)
240 if os.IsNotExist(err) && v.fixRace(loc) {
241 // The data object got trashed in a race, but fixRace
243 } else if err != nil {
246 err = v.Bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{})
247 return v.translateError(err)
250 func (v *S3Volume) Mtime(loc string) (time.Time, error) {
251 _, err := v.Bucket.Head(loc, nil)
253 return zeroTime, v.translateError(err)
255 resp, err := v.Bucket.Head("recent/"+loc, nil)
256 err = v.translateError(err)
257 if os.IsNotExist(err) {
258 // The data object X exists, but recent/X is missing.
259 err = v.Bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{})
261 log.Printf("error: creating %q: %s", "recent/"+loc, err)
262 return zeroTime, v.translateError(err)
264 log.Printf("info: created %q to migrate existing block to new storage scheme", "recent/"+loc)
265 resp, err = v.Bucket.Head("recent/"+loc, nil)
267 log.Printf("error: created %q but HEAD failed: %s", "recent/"+loc, err)
268 return zeroTime, v.translateError(err)
270 } else if err != nil {
271 // HEAD recent/X failed for some other reason.
274 return v.lastModified(resp)
277 func (v *S3Volume) IndexTo(prefix string, writer io.Writer) error {
278 // Use a merge sort to find matching sets of X and recent/X.
282 PageSize: v.indexPageSize,
286 Prefix: "recent/"+prefix,
287 PageSize: v.indexPageSize,
289 for data, recent := dataL.First(), recentL.First(); data != nil; data = dataL.Next() {
291 // Conveniently, "recent/*" and "trash/*" are
292 // lexically greater than all hex-encoded data
293 // hashes, so stopping here avoids iterating
294 // over all of them needlessly with dataL.
297 if !v.isKeepBlock(data.Key) {
301 // stamp is the list entry we should use to report the
302 // last-modified time for this data block: it will be
303 // the recent/X entry if one exists, otherwise the
304 // entry for the data block itself.
307 // Advance to the corresponding recent/X marker, if any
309 if cmp := strings.Compare(recent.Key[7:], data.Key); cmp < 0 {
310 recent = recentL.Next()
314 recent = recentL.Next()
317 // recent/X marker is missing: we'll
318 // use the timestamp on the data
323 t, err := time.Parse(time.RFC3339, stamp.LastModified)
327 fmt.Fprintf(writer, "%s+%d %d\n", data.Key, data.Size, t.UnixNano())
332 // Trash a Keep block.
333 func (v *S3Volume) Trash(loc string) error {
335 return MethodDisabledError
337 if t, err := v.Mtime(loc); err != nil {
339 } else if time.Since(t) < blobSignatureTTL {
342 if trashLifetime == 0 {
344 return ErrS3TrashNotAvailable
346 return v.Bucket.Del(loc)
349 // Make sure we're not in the race window.
351 resp, err := v.Bucket.Head("trash/"+loc, nil)
352 err = v.translateError(err)
353 if os.IsNotExist(err) {
354 // OK, trash/X doesn't exist so we're not in
356 } else if err != nil {
357 // Error looking up trash/X. Unsafe to proceed
358 // without knowing whether we're in the race
361 } else if t, err := v.lastModified(resp); err != nil {
362 // Can't parse timestamp
364 } else if safeWindow := t.Add(trashLifetime).Sub(time.Now().Add(v.raceWindow)); safeWindow <= 0 {
365 // We can't count on "touch trash/X" to
366 // prolong trash/X's lifetime. The new
367 // timestamp might not become visible until
368 // now+raceWindow, and EmptyTrash is allowed
369 // to delete trash/X before then.
370 return fmt.Errorf("same block is already in trash, and safe window ended %s ago", -safeWindow)
374 err := v.safeCopy("trash/"+loc, loc)
378 return v.translateError(v.Bucket.Del(loc))
381 func (v *S3Volume) safeCopy(dst, src string) error {
382 resp, err := v.Bucket.PutCopy(dst, s3ACL, s3.CopyOptions{
383 ContentType: "application/octet-stream",
384 MetadataDirective: "REPLACE",
385 }, v.Bucket.Name+"/"+src)
386 err = v.translateError(err)
390 if t, err := time.Parse(time.RFC3339Nano, resp.LastModified); err != nil {
391 return fmt.Errorf("PutCopy succeeded but did not return a timestamp: %q: %s", resp.LastModified, err)
392 } else if time.Now().Sub(t) > maxClockSkew {
393 return fmt.Errorf("PutCopy succeeded but returned an old timestamp: %q: %s", resp.LastModified, t)
398 // Get the LastModified header from resp, and parse it as RFC1123 or
399 // -- if it isn't valid RFC1123 -- as Amazon's variant of RFC1123.
400 func (v *S3Volume) lastModified(resp *http.Response) (t time.Time, err error) {
401 s := resp.Header.Get("Last-Modified")
402 t, err = time.Parse(time.RFC1123, s)
403 if err != nil && s != "" {
404 // AWS example is "Sun, 1 Jan 2006 12:00:00 GMT",
405 // which isn't quite "Sun, 01 Jan 2006 12:00:00 GMT"
406 // as required by HTTP spec. If it's not a valid HTTP
407 // header value, it's probably AWS (or s3test) giving
408 // us a nearly-RFC1123 timestamp.
409 t, err = time.Parse(nearlyRFC1123, s)
414 func (v *S3Volume) Untrash(loc string) error {
415 return v.safeCopy(loc, "trash/"+loc)
418 func (v *S3Volume) Status() *VolumeStatus {
419 return &VolumeStatus{
421 BytesFree: BlockSize * 1000,
426 func (v *S3Volume) String() string {
427 return fmt.Sprintf("s3-bucket:%+q", v.Bucket.Name)
430 func (v *S3Volume) Writable() bool {
433 func (v *S3Volume) Replication() int {
437 var s3KeepBlockRegexp = regexp.MustCompile(`^[0-9a-f]{32}$`)
439 func (v *S3Volume) isKeepBlock(s string) bool {
440 return s3KeepBlockRegexp.MatchString(s)
443 // fixRace(X) is called when "recent/X" exists but "X" doesn't
444 // exist. If the timestamps on "recent/"+loc and "trash/"+loc indicate
445 // there was a race between Put and Trash, fixRace recovers from the
446 // race by Untrashing the block.
447 func (v *S3Volume) fixRace(loc string) bool {
448 trash, err := v.Bucket.Head("trash/"+loc, nil)
450 if !os.IsNotExist(v.translateError(err)) {
451 log.Printf("error: fixRace: HEAD %q: %s", "trash/"+loc, err)
455 trashTime, err := v.lastModified(trash)
457 log.Printf("error: fixRace: parse %q: %s", trash.Header.Get("Last-Modified"), err)
461 recent, err := v.Bucket.Head("recent/"+loc, nil)
463 log.Printf("error: fixRace: HEAD %q: %s", "recent/"+loc, err)
466 recentTime, err := v.lastModified(recent)
468 log.Printf("error: fixRace: parse %q: %s", recent.Header.Get("Last-Modified"), err)
472 ageWhenTrashed := trashTime.Sub(recentTime)
473 if ageWhenTrashed >= blobSignatureTTL {
474 // No evidence of a race: block hasn't been written
475 // since it became eligible for Trash. No fix needed.
479 log.Printf("notice: fixRace: %q: trashed at %s but touched at %s (age when trashed = %s < %s)", loc, trashTime, recentTime, ageWhenTrashed, blobSignatureTTL)
480 log.Printf("notice: fixRace: copying %q to %q to recover from race between Put/Touch and Trash", "recent/"+loc, loc)
481 err = v.safeCopy(loc, "trash/"+loc)
483 log.Printf("error: fixRace: %s", err)
489 func (v *S3Volume) translateError(err error) error {
490 switch err := err.(type) {
492 if (err.StatusCode == http.StatusNotFound && err.Code == "NoSuchKey") ||
493 strings.Contains(err.Error(), "Not Found") {
494 return os.ErrNotExist
496 // Other 404 errors like NoSuchVersion and
497 // NoSuchBucket are different problems which should
498 // get called out downstream, so we don't convert them
499 // to os.ErrNotExist.
504 // EmptyTrash looks for trashed blocks that exceeded trashLifetime
505 // and deletes them from the volume.
506 func (v *S3Volume) EmptyTrash() {
507 // Use a merge sort to find matching sets of trash/X and recent/X.
511 PageSize: v.indexPageSize,
513 // Define "ready to delete" as "...when EmptyTrash started".
515 for trash := trashL.First(); trash != nil; trash = trashL.Next() {
517 if !v.isKeepBlock(loc) {
520 recent, err := v.Bucket.Head("recent/"+loc, nil)
522 log.Printf("warning: %s: EmptyTrash: cannot delete trash %q with no corresponding recent/* marker", v, trash.Key)
525 trashT, err := time.Parse(time.RFC3339, trash.LastModified)
529 recentT, err := v.lastModified(recent)
533 if trashT.Sub(recentT) < blobSignatureTTL {
537 if now.Sub(trashT) < trashLifetime {
540 err = v.Bucket.Del(trash.Key)
542 log.Printf("warning: %s: EmptyTrash: deleting %q: %s", v, trash.Key, err)
545 _, err = v.Bucket.Head(loc, nil)
546 if os.IsNotExist(err) {
547 err = v.Bucket.Del("recent/"+loc)
549 log.Printf("warning: %s: EmptyTrash: deleting %q: %s", v, "recent/"+loc, err)
551 } else if err != nil {
552 log.Printf("warning: %s: EmptyTrash: HEAD %q: %s", v, "recent/"+loc, err)
555 if err := trashL.Error(); err != nil {
556 log.Printf("error: %s: EmptyTrash: lister: %s", v, err)
560 type s3Lister struct {
569 // First fetches the first page and returns the first item. It returns
570 // nil if the response is the empty set or an error occurs.
571 func (lister *s3Lister) First() *s3.Key {
576 // Next returns the next item, fetching the next page if necessary. It
577 // returns nil if the last available item has already been fetched, or
579 func (lister *s3Lister) Next() *s3.Key {
580 if len(lister.buf) == 0 && lister.nextMarker != "" {
586 // Return the most recent error encountered by First or Next.
587 func (lister *s3Lister) Error() error {
591 func (lister *s3Lister) getPage() {
592 resp, err := lister.Bucket.List(lister.Prefix, "", lister.nextMarker, lister.PageSize)
593 lister.nextMarker = ""
598 if resp.IsTruncated {
599 lister.nextMarker = resp.NextMarker
601 lister.buf = make([]s3.Key, 0, len(resp.Contents))
602 for _, key := range resp.Contents {
603 if !strings.HasPrefix(key.Key, lister.Prefix) {
604 log.Printf("warning: s3Lister: S3 Bucket.List(prefix=%q) returned key %q", lister.Prefix, key.Key)
607 lister.buf = append(lister.buf, key)
611 func (lister *s3Lister) pop() (k *s3.Key) {
612 if len(lister.buf) > 0 {
614 lister.buf = lister.buf[1:]