16 "github.com/AdRoll/goamz/aws"
17 "github.com/AdRoll/goamz/s3"
21 ErrS3TrashDisabled = fmt.Errorf("trash function is disabled 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 // getReader wraps (Bucket)GetReader.
167 // In situations where (Bucket)GetReader would fail because the block
168 // disappeared in a Trash race, getReader calls fixRace to recover the
169 // data, and tries again.
170 func (v *S3Volume) getReader(loc string) (rdr io.ReadCloser, err error) {
171 rdr, err = v.Bucket.GetReader(loc)
172 err = v.translateError(err)
173 if err == nil || !os.IsNotExist(err) {
176 _, err = v.Bucket.Head("recent/"+loc, nil)
177 err = v.translateError(err)
179 // If we can't read recent/X, there's no point in
180 // trying fixRace. Give up.
187 rdr, err = v.Bucket.GetReader(loc)
189 log.Printf("warning: reading %s after successful fixRace: %s", loc, err)
190 err = v.translateError(err)
195 func (v *S3Volume) Get(loc string, buf []byte) (int, error) {
196 rdr, err := v.getReader(loc)
201 n, err := io.ReadFull(rdr, buf)
203 case nil, io.EOF, io.ErrUnexpectedEOF:
206 return 0, v.translateError(err)
210 func (v *S3Volume) Compare(loc string, expect []byte) error {
211 rdr, err := v.getReader(loc)
216 return v.translateError(compareReaderWithBuf(rdr, expect, loc[:32]))
219 func (v *S3Volume) Put(loc string, block []byte) error {
221 return MethodDisabledError
225 md5, err := hex.DecodeString(loc)
229 opts.ContentMD5 = base64.StdEncoding.EncodeToString(md5)
231 err := v.Bucket.Put(loc, block, "application/octet-stream", s3ACL, opts)
233 return v.translateError(err)
235 err = v.Bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{})
236 return v.translateError(err)
239 func (v *S3Volume) Touch(loc string) error {
241 return MethodDisabledError
243 _, err := v.Bucket.Head(loc, nil)
244 err = v.translateError(err)
245 if os.IsNotExist(err) && v.fixRace(loc) {
246 // The data object got trashed in a race, but fixRace
248 } else if err != nil {
251 err = v.Bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{})
252 return v.translateError(err)
255 func (v *S3Volume) Mtime(loc string) (time.Time, error) {
256 _, err := v.Bucket.Head(loc, nil)
258 return zeroTime, v.translateError(err)
260 resp, err := v.Bucket.Head("recent/"+loc, nil)
261 err = v.translateError(err)
262 if os.IsNotExist(err) {
263 // The data object X exists, but recent/X is missing.
264 err = v.Bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{})
266 log.Printf("error: creating %q: %s", "recent/"+loc, err)
267 return zeroTime, v.translateError(err)
269 log.Printf("info: created %q to migrate existing block to new storage scheme", "recent/"+loc)
270 resp, err = v.Bucket.Head("recent/"+loc, nil)
272 log.Printf("error: created %q but HEAD failed: %s", "recent/"+loc, err)
273 return zeroTime, v.translateError(err)
275 } else if err != nil {
276 // HEAD recent/X failed for some other reason.
279 return v.lastModified(resp)
282 func (v *S3Volume) IndexTo(prefix string, writer io.Writer) error {
283 // Use a merge sort to find matching sets of X and recent/X.
287 PageSize: v.indexPageSize,
291 Prefix: "recent/"+prefix,
292 PageSize: v.indexPageSize,
294 for data, recent := dataL.First(), recentL.First(); data != nil; data = dataL.Next() {
296 // Conveniently, "recent/*" and "trash/*" are
297 // lexically greater than all hex-encoded data
298 // hashes, so stopping here avoids iterating
299 // over all of them needlessly with dataL.
302 if !v.isKeepBlock(data.Key) {
306 // stamp is the list entry we should use to report the
307 // last-modified time for this data block: it will be
308 // the recent/X entry if one exists, otherwise the
309 // entry for the data block itself.
312 // Advance to the corresponding recent/X marker, if any
314 if cmp := strings.Compare(recent.Key[7:], data.Key); cmp < 0 {
315 recent = recentL.Next()
319 recent = recentL.Next()
322 // recent/X marker is missing: we'll
323 // use the timestamp on the data
328 t, err := time.Parse(time.RFC3339, stamp.LastModified)
332 fmt.Fprintf(writer, "%s+%d %d\n", data.Key, data.Size, t.UnixNano())
337 // Trash a Keep block.
338 func (v *S3Volume) Trash(loc string) error {
340 return MethodDisabledError
342 if t, err := v.Mtime(loc); err != nil {
344 } else if time.Since(t) < blobSignatureTTL {
347 if trashLifetime == 0 {
349 return ErrS3TrashDisabled
351 return v.Bucket.Del(loc)
353 err := v.checkRaceWindow(loc)
357 err = v.safeCopy("trash/"+loc, loc)
361 return v.translateError(v.Bucket.Del(loc))
364 // checkRaceWindow returns a non-nil error if trash/loc is, or might
365 // be, in the race window (i.e., it's not safe to trash loc).
366 func (v *S3Volume) checkRaceWindow(loc string) error {
367 resp, err := v.Bucket.Head("trash/"+loc, nil)
368 err = v.translateError(err)
369 if os.IsNotExist(err) {
370 // OK, trash/X doesn't exist so we're not in the race
373 } else if err != nil {
374 // Error looking up trash/X. We don't know whether
375 // we're in the race window
378 t, err := v.lastModified(resp)
380 // Can't parse timestamp
383 safeWindow := t.Add(trashLifetime).Sub(time.Now().Add(v.raceWindow))
385 // We can't count on "touch trash/X" to prolong
386 // trash/X's lifetime. The new timestamp might not
387 // become visible until now+raceWindow, and EmptyTrash
388 // is allowed to delete trash/X before then.
389 return fmt.Errorf("same block is already in trash, and safe window ended %s ago", -safeWindow)
391 // trash/X exists, but it won't be eligible for deletion until
392 // after now+raceWindow, so it's safe to overwrite it.
396 func (v *S3Volume) safeCopy(dst, src string) error {
397 resp, err := v.Bucket.PutCopy(dst, s3ACL, s3.CopyOptions{
398 ContentType: "application/octet-stream",
399 MetadataDirective: "REPLACE",
400 }, v.Bucket.Name+"/"+src)
401 err = v.translateError(err)
405 if t, err := time.Parse(time.RFC3339Nano, resp.LastModified); err != nil {
406 return fmt.Errorf("PutCopy succeeded but did not return a timestamp: %q: %s", resp.LastModified, err)
407 } else if time.Now().Sub(t) > maxClockSkew {
408 return fmt.Errorf("PutCopy succeeded but returned an old timestamp: %q: %s", resp.LastModified, t)
413 // Get the LastModified header from resp, and parse it as RFC1123 or
414 // -- if it isn't valid RFC1123 -- as Amazon's variant of RFC1123.
415 func (v *S3Volume) lastModified(resp *http.Response) (t time.Time, err error) {
416 s := resp.Header.Get("Last-Modified")
417 t, err = time.Parse(time.RFC1123, s)
418 if err != nil && s != "" {
419 // AWS example is "Sun, 1 Jan 2006 12:00:00 GMT",
420 // which isn't quite "Sun, 01 Jan 2006 12:00:00 GMT"
421 // as required by HTTP spec. If it's not a valid HTTP
422 // header value, it's probably AWS (or s3test) giving
423 // us a nearly-RFC1123 timestamp.
424 t, err = time.Parse(nearlyRFC1123, s)
429 func (v *S3Volume) Untrash(loc string) error {
430 err := v.safeCopy(loc, "trash/"+loc)
434 err = v.Bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{})
435 return v.translateError(err)
438 func (v *S3Volume) Status() *VolumeStatus {
439 return &VolumeStatus{
441 BytesFree: BlockSize * 1000,
446 func (v *S3Volume) String() string {
447 return fmt.Sprintf("s3-bucket:%+q", v.Bucket.Name)
450 func (v *S3Volume) Writable() bool {
453 func (v *S3Volume) Replication() int {
457 var s3KeepBlockRegexp = regexp.MustCompile(`^[0-9a-f]{32}$`)
459 func (v *S3Volume) isKeepBlock(s string) bool {
460 return s3KeepBlockRegexp.MatchString(s)
463 // fixRace(X) is called when "recent/X" exists but "X" doesn't
464 // exist. If the timestamps on "recent/"+loc and "trash/"+loc indicate
465 // there was a race between Put and Trash, fixRace recovers from the
466 // race by Untrashing the block.
467 func (v *S3Volume) fixRace(loc string) bool {
468 trash, err := v.Bucket.Head("trash/"+loc, nil)
470 if !os.IsNotExist(v.translateError(err)) {
471 log.Printf("error: fixRace: HEAD %q: %s", "trash/"+loc, err)
475 trashTime, err := v.lastModified(trash)
477 log.Printf("error: fixRace: parse %q: %s", trash.Header.Get("Last-Modified"), err)
481 recent, err := v.Bucket.Head("recent/"+loc, nil)
483 log.Printf("error: fixRace: HEAD %q: %s", "recent/"+loc, err)
486 recentTime, err := v.lastModified(recent)
488 log.Printf("error: fixRace: parse %q: %s", recent.Header.Get("Last-Modified"), err)
492 ageWhenTrashed := trashTime.Sub(recentTime)
493 if ageWhenTrashed >= blobSignatureTTL {
494 // No evidence of a race: block hasn't been written
495 // since it became eligible for Trash. No fix needed.
499 log.Printf("notice: fixRace: %q: trashed at %s but touched at %s (age when trashed = %s < %s)", loc, trashTime, recentTime, ageWhenTrashed, blobSignatureTTL)
500 log.Printf("notice: fixRace: copying %q to %q to recover from race between Put/Touch and Trash", "recent/"+loc, loc)
501 err = v.safeCopy(loc, "trash/"+loc)
503 log.Printf("error: fixRace: %s", err)
509 func (v *S3Volume) translateError(err error) error {
510 switch err := err.(type) {
512 if (err.StatusCode == http.StatusNotFound && err.Code == "NoSuchKey") ||
513 strings.Contains(err.Error(), "Not Found") {
514 return os.ErrNotExist
516 // Other 404 errors like NoSuchVersion and
517 // NoSuchBucket are different problems which should
518 // get called out downstream, so we don't convert them
519 // to os.ErrNotExist.
524 // EmptyTrash looks for trashed blocks that exceeded trashLifetime
525 // and deletes them from the volume.
526 func (v *S3Volume) EmptyTrash() {
527 // Use a merge sort to find matching sets of trash/X and recent/X.
531 PageSize: v.indexPageSize,
533 // Define "ready to delete" as "...when EmptyTrash started".
535 for trash := trashL.First(); trash != nil; trash = trashL.Next() {
537 if !v.isKeepBlock(loc) {
540 recent, err := v.Bucket.Head("recent/"+loc, nil)
542 log.Printf("warning: %s: EmptyTrash: cannot delete trash %q with no corresponding recent/* marker", v, trash.Key)
545 trashT, err := time.Parse(time.RFC3339, trash.LastModified)
547 log.Printf("warning: %s: EmptyTrash: %q: parse %q: %s", v, trash.Key, trash.LastModified, err)
550 recentT, err := v.lastModified(recent)
552 log.Printf("warning: %s: EmptyTrash: %q: parse %q: %s", v, "recent/"+loc, recent.Header.Get("Last-Modified"), err)
555 if trashT.Sub(recentT) < blobSignatureTTL {
559 if now.Sub(trashT) < trashLifetime {
562 err = v.Bucket.Del(trash.Key)
564 log.Printf("warning: %s: EmptyTrash: deleting %q: %s", v, trash.Key, err)
567 _, err = v.Bucket.Head(loc, nil)
568 if os.IsNotExist(err) {
569 err = v.Bucket.Del("recent/"+loc)
571 log.Printf("warning: %s: EmptyTrash: deleting %q: %s", v, "recent/"+loc, err)
573 } else if err != nil {
574 log.Printf("warning: %s: EmptyTrash: HEAD %q: %s", v, "recent/"+loc, err)
577 if err := trashL.Error(); err != nil {
578 log.Printf("error: %s: EmptyTrash: lister: %s", v, err)
582 type s3Lister struct {
591 // First fetches the first page and returns the first item. It returns
592 // nil if the response is the empty set or an error occurs.
593 func (lister *s3Lister) First() *s3.Key {
598 // Next returns the next item, fetching the next page if necessary. It
599 // returns nil if the last available item has already been fetched, or
601 func (lister *s3Lister) Next() *s3.Key {
602 if len(lister.buf) == 0 && lister.nextMarker != "" {
608 // Return the most recent error encountered by First or Next.
609 func (lister *s3Lister) Error() error {
613 func (lister *s3Lister) getPage() {
614 resp, err := lister.Bucket.List(lister.Prefix, "", lister.nextMarker, lister.PageSize)
615 lister.nextMarker = ""
620 if resp.IsTruncated {
621 lister.nextMarker = resp.NextMarker
623 lister.buf = make([]s3.Key, 0, len(resp.Contents))
624 for _, key := range resp.Contents {
625 if !strings.HasPrefix(key.Key, lister.Prefix) {
626 log.Printf("warning: s3Lister: S3 Bucket.List(prefix=%q) returned key %q", lister.Prefix, key.Key)
629 lister.buf = append(lister.buf, key)
633 func (lister *s3Lister) pop() (k *s3.Key) {
634 if len(lister.buf) > 0 {
636 lister.buf = lister.buf[1:]