X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/252a5f7f290567f7cbcc9897a879c0a7ebe64e90..1d656f4f1ec1f890a7677e748bea43a08cfa0b6c:/services/keepstore/s3_volume.go diff --git a/services/keepstore/s3_volume.go b/services/keepstore/s3_volume.go index 79a680d58a..caed35b670 100644 --- a/services/keepstore/s3_volume.go +++ b/services/keepstore/s3_volume.go @@ -10,14 +10,19 @@ import ( "net/http" "os" "regexp" + "strings" + "sync" "time" + "git.curoverse.com/arvados.git/sdk/go/arvados" "github.com/AdRoll/goamz/aws" "github.com/AdRoll/goamz/s3" ) var ( - ErrS3DeleteNotAvailable = fmt.Errorf("delete without -s3-unsafe-delete is not implemented") + // ErrS3TrashDisabled is returned by Trash if that operation + // is impossible with the current config. + ErrS3TrashDisabled = fmt.Errorf("trash function is disabled because -trash-lifetime=0 and -s3-unsafe-delete=false") s3AccessKeyFile string s3SecretKeyFile string @@ -25,6 +30,7 @@ var ( s3Endpoint string s3Replication int s3UnsafeDelete bool + s3RaceWindow time.Duration s3ACL = s3.Private ) @@ -35,64 +41,50 @@ const ( ) type s3VolumeAdder struct { - *volumeSet + *Config +} + +// String implements flag.Value +func (s *s3VolumeAdder) String() string { + return "-" } func (s *s3VolumeAdder) Set(bucketName string) error { - if trashLifetime != 0 { - return ErrNotImplemented - } if bucketName == "" { return fmt.Errorf("no container name given") } if s3AccessKeyFile == "" || s3SecretKeyFile == "" { return fmt.Errorf("-s3-access-key-file and -s3-secret-key-file arguments must given before -s3-bucket-volume") } - region, ok := aws.Regions[s3RegionName] - if s3Endpoint == "" { - if !ok { - return fmt.Errorf("unrecognized region %+q; try specifying -s3-endpoint instead", s3RegionName) - } - } else { - if ok { - return fmt.Errorf("refusing to use AWS region name %+q with endpoint %+q; "+ - "specify empty endpoint (\"-s3-endpoint=\") or use a different region name", s3RegionName, s3Endpoint) - } - region = aws.Region{ - Name: s3RegionName, - S3Endpoint: s3Endpoint, - } - } - var err error - var auth aws.Auth - auth.AccessKey, err = readKeyFromFile(s3AccessKeyFile) - if err != nil { - return err - } - auth.SecretKey, err = readKeyFromFile(s3SecretKeyFile) - if err != nil { - return err - } - if flagSerializeIO { + if deprecated.flagSerializeIO { log.Print("Notice: -serialize is not supported by s3-bucket volumes.") } - v := NewS3Volume(auth, region, bucketName, flagReadonly, s3Replication) - if err := v.Check(); err != nil { - return err - } - *s.volumeSet = append(*s.volumeSet, v) + s.Config.Volumes = append(s.Config.Volumes, &S3Volume{ + Bucket: bucketName, + AccessKeyFile: s3AccessKeyFile, + SecretKeyFile: s3SecretKeyFile, + Endpoint: s3Endpoint, + Region: s3RegionName, + RaceWindow: arvados.Duration(s3RaceWindow), + S3Replication: s3Replication, + UnsafeDelete: s3UnsafeDelete, + ReadOnly: deprecated.flagReadonly, + IndexPageSize: 1000, + }) return nil } func s3regions() (okList []string) { - for r, _ := range aws.Regions { + for r := range aws.Regions { okList = append(okList, r) } return } func init() { - flag.Var(&s3VolumeAdder{&volumes}, + VolumeTypes = append(VolumeTypes, func() VolumeWithExamples { return &S3Volume{} }) + + flag.Var(&s3VolumeAdder{theConfig}, "s3-bucket-volume", "Use the given bucket as a storage volume. Can be given multiple times.") flag.StringVar( @@ -109,12 +101,17 @@ func init() { &s3AccessKeyFile, "s3-access-key-file", "", - "File containing the access key used for subsequent -s3-bucket-volume arguments.") + "`File` containing the access key used for subsequent -s3-bucket-volume arguments.") flag.StringVar( &s3SecretKeyFile, "s3-secret-key-file", "", - "File containing the secret key used for subsequent -s3-bucket-volume arguments.") + "`File` containing the secret key used for subsequent -s3-bucket-volume arguments.") + flag.DurationVar( + &s3RaceWindow, + "s3-race-window", + 24*time.Hour, + "Maximum eventual consistency latency for subsequent -s3-bucket-volume arguments.") flag.IntVar( &s3Replication, "s3-replication", @@ -127,60 +124,152 @@ func init() { "EXPERIMENTAL. Enable deletion (garbage collection), even though there are known race conditions that can cause data loss.") } +// S3Volume implements Volume using an S3 bucket. type S3Volume struct { - *s3.Bucket - readonly bool - replication int - indexPageSize int -} - -// NewS3Volume returns a new S3Volume using the given auth, region, -// and bucket name. The replication argument specifies the replication -// level to report when writing data. -func NewS3Volume(auth aws.Auth, region aws.Region, bucket string, readonly bool, replication int) *S3Volume { - return &S3Volume{ - Bucket: &s3.Bucket{ - S3: s3.New(auth, region), - Name: bucket, + AccessKeyFile string + SecretKeyFile string + Endpoint string + Region string + Bucket string + LocationConstraint bool + IndexPageSize int + S3Replication int + RaceWindow arvados.Duration + ReadOnly bool + UnsafeDelete bool + + bucket *s3.Bucket + + startOnce sync.Once +} + +// Examples implements VolumeWithExamples. +func (*S3Volume) Examples() []Volume { + return []Volume{ + &S3Volume{ + AccessKeyFile: "/etc/aws_s3_access_key.txt", + SecretKeyFile: "/etc/aws_s3_secret_key.txt", + Endpoint: "", + Region: "us-east-1", + Bucket: "example-bucket-name", + IndexPageSize: 1000, + S3Replication: 2, + RaceWindow: arvados.Duration(24 * time.Hour), + }, + &S3Volume{ + AccessKeyFile: "/etc/gce_s3_access_key.txt", + SecretKeyFile: "/etc/gce_s3_secret_key.txt", + Endpoint: "https://storage.googleapis.com", + Region: "", + Bucket: "example-bucket-name", + IndexPageSize: 1000, + S3Replication: 2, + RaceWindow: arvados.Duration(24 * time.Hour), }, - readonly: readonly, - replication: replication, - indexPageSize: 1000, } } -func (v *S3Volume) Check() error { +// Type implements Volume. +func (*S3Volume) Type() string { + return "S3" +} + +// Start populates private fields and verifies the configuration is +// valid. +func (v *S3Volume) Start() error { + region, ok := aws.Regions[v.Region] + if v.Endpoint == "" { + if !ok { + return fmt.Errorf("unrecognized region %+q; try specifying -s3-endpoint instead", v.Region) + } + } else if ok { + return fmt.Errorf("refusing to use AWS region name %+q with endpoint %+q; "+ + "specify empty endpoint (\"-s3-endpoint=\") or use a different region name", v.Region, v.Endpoint) + } else { + region = aws.Region{ + Name: v.Region, + S3Endpoint: v.Endpoint, + S3LocationConstraint: v.LocationConstraint, + } + } + + var err error + var auth aws.Auth + auth.AccessKey, err = readKeyFromFile(v.AccessKeyFile) + if err != nil { + return err + } + auth.SecretKey, err = readKeyFromFile(v.SecretKeyFile) + if err != nil { + return err + } + v.bucket = &s3.Bucket{ + S3: s3.New(auth, region), + Name: v.Bucket, + } return nil } -func (v *S3Volume) Get(loc string) ([]byte, error) { - rdr, err := v.Bucket.GetReader(loc) +// getReader wraps (Bucket)GetReader. +// +// In situations where (Bucket)GetReader would fail because the block +// disappeared in a Trash race, getReader calls fixRace to recover the +// data, and tries again. +func (v *S3Volume) getReader(loc string) (rdr io.ReadCloser, err error) { + rdr, err = v.bucket.GetReader(loc) + err = v.translateError(err) + if err == nil || !os.IsNotExist(err) { + return + } + _, err = v.bucket.Head("recent/"+loc, nil) + err = v.translateError(err) + if err != nil { + // If we can't read recent/X, there's no point in + // trying fixRace. Give up. + return + } + if !v.fixRace(loc) { + err = os.ErrNotExist + return + } + rdr, err = v.bucket.GetReader(loc) if err != nil { - return nil, v.translateError(err) + log.Printf("warning: reading %s after successful fixRace: %s", loc, err) + err = v.translateError(err) + } + return +} + +// Get a block: copy the block data into buf, and return the number of +// bytes copied. +func (v *S3Volume) Get(loc string, buf []byte) (int, error) { + rdr, err := v.getReader(loc) + if err != nil { + return 0, err } defer rdr.Close() - buf := bufs.Get(BlockSize) n, err := io.ReadFull(rdr, buf) switch err { case nil, io.EOF, io.ErrUnexpectedEOF: - return buf[:n], nil + return n, nil default: - bufs.Put(buf) - return nil, v.translateError(err) + return 0, v.translateError(err) } } +// Compare the given data with the stored data. func (v *S3Volume) Compare(loc string, expect []byte) error { - rdr, err := v.Bucket.GetReader(loc) + rdr, err := v.getReader(loc) if err != nil { - return v.translateError(err) + return err } defer rdr.Close() return v.translateError(compareReaderWithBuf(rdr, expect, loc[:32])) } +// Put writes a block. func (v *S3Volume) Put(loc string, block []byte) error { - if v.readonly { + if v.ReadOnly { return MethodDisabledError } var opts s3.Options @@ -191,99 +280,225 @@ func (v *S3Volume) Put(loc string, block []byte) error { } opts.ContentMD5 = base64.StdEncoding.EncodeToString(md5) } - return v.translateError( - v.Bucket.Put( - loc, block, "application/octet-stream", s3ACL, opts)) + err := v.bucket.Put(loc, block, "application/octet-stream", s3ACL, opts) + if err != nil { + return v.translateError(err) + } + err = v.bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{}) + return v.translateError(err) } +// Touch sets the timestamp for the given locator to the current time. func (v *S3Volume) Touch(loc string) error { - if v.readonly { + if v.ReadOnly { return MethodDisabledError } - result, err := v.Bucket.PutCopy(loc, s3ACL, s3.CopyOptions{ - ContentType: "application/octet-stream", - MetadataDirective: "REPLACE", - }, v.Bucket.Name+"/"+loc) - if err != nil { - return v.translateError(err) - } - t, err := time.Parse(time.RFC3339, result.LastModified) - if err != nil { + _, err := v.bucket.Head(loc, nil) + err = v.translateError(err) + if os.IsNotExist(err) && v.fixRace(loc) { + // The data object got trashed in a race, but fixRace + // rescued it. + } else if err != nil { return err } - if time.Since(t) > maxClockSkew { - return fmt.Errorf("PutCopy returned old LastModified %s => %s (%s ago)", result.LastModified, t, time.Since(t)) - } - return nil + err = v.bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{}) + return v.translateError(err) } +// Mtime returns the stored timestamp for the given locator. func (v *S3Volume) Mtime(loc string) (time.Time, error) { - resp, err := v.Bucket.Head(loc, nil) + _, err := v.bucket.Head(loc, nil) if err != nil { return zeroTime, v.translateError(err) } - hdr := resp.Header.Get("Last-Modified") - t, err := time.Parse(time.RFC1123, hdr) - if err != nil && hdr != "" { - // AWS example is "Sun, 1 Jan 2006 12:00:00 GMT", - // which isn't quite "Sun, 01 Jan 2006 12:00:00 GMT" - // as required by HTTP spec. If it's not a valid HTTP - // header value, it's probably AWS (or s3test) giving - // us a nearly-RFC1123 timestamp. - t, err = time.Parse(nearlyRFC1123, hdr) + resp, err := v.bucket.Head("recent/"+loc, nil) + err = v.translateError(err) + if os.IsNotExist(err) { + // The data object X exists, but recent/X is missing. + err = v.bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{}) + if err != nil { + log.Printf("error: creating %q: %s", "recent/"+loc, err) + return zeroTime, v.translateError(err) + } + log.Printf("info: created %q to migrate existing block to new storage scheme", "recent/"+loc) + resp, err = v.bucket.Head("recent/"+loc, nil) + if err != nil { + log.Printf("error: created %q but HEAD failed: %s", "recent/"+loc, err) + return zeroTime, v.translateError(err) + } + } else if err != nil { + // HEAD recent/X failed for some other reason. + return zeroTime, err } - return t, err + return v.lastModified(resp) } +// IndexTo writes a complete list of locators with the given prefix +// for which Get() can retrieve data. func (v *S3Volume) IndexTo(prefix string, writer io.Writer) error { - nextMarker := "" - for { - listResp, err := v.Bucket.List(prefix, "", nextMarker, v.indexPageSize) - if err != nil { - return err + // Use a merge sort to find matching sets of X and recent/X. + dataL := s3Lister{ + Bucket: v.bucket, + Prefix: prefix, + PageSize: v.IndexPageSize, + } + recentL := s3Lister{ + Bucket: v.bucket, + Prefix: "recent/" + prefix, + PageSize: v.IndexPageSize, + } + for data, recent := dataL.First(), recentL.First(); data != nil; data = dataL.Next() { + if data.Key >= "g" { + // Conveniently, "recent/*" and "trash/*" are + // lexically greater than all hex-encoded data + // hashes, so stopping here avoids iterating + // over all of them needlessly with dataL. + break } - for _, key := range listResp.Contents { - t, err := time.Parse(time.RFC3339, key.LastModified) - if err != nil { - return err - } - if !v.isKeepBlock(key.Key) { + if !v.isKeepBlock(data.Key) { + continue + } + + // stamp is the list entry we should use to report the + // last-modified time for this data block: it will be + // the recent/X entry if one exists, otherwise the + // entry for the data block itself. + stamp := data + + // Advance to the corresponding recent/X marker, if any + for recent != nil { + if cmp := strings.Compare(recent.Key[7:], data.Key); cmp < 0 { + recent = recentL.Next() continue + } else if cmp == 0 { + stamp = recent + recent = recentL.Next() + break + } else { + // recent/X marker is missing: we'll + // use the timestamp on the data + // object. + break } - fmt.Fprintf(writer, "%s+%d %d\n", key.Key, key.Size, t.Unix()) } - if !listResp.IsTruncated { - break + t, err := time.Parse(time.RFC3339, stamp.LastModified) + if err != nil { + return err } - nextMarker = listResp.NextMarker + fmt.Fprintf(writer, "%s+%d %d\n", data.Key, data.Size, t.UnixNano()) } return nil } // Trash a Keep block. func (v *S3Volume) Trash(loc string) error { - if v.readonly { + if v.ReadOnly { return MethodDisabledError } - if trashLifetime != 0 { - return ErrNotImplemented - } if t, err := v.Mtime(loc); err != nil { return err - } else if time.Since(t) < blobSignatureTTL { + } else if time.Since(t) < theConfig.BlobSignatureTTL.Duration() { + return nil + } + if theConfig.TrashLifetime == 0 { + if !s3UnsafeDelete { + return ErrS3TrashDisabled + } + return v.bucket.Del(loc) + } + err := v.checkRaceWindow(loc) + if err != nil { + return err + } + err = v.safeCopy("trash/"+loc, loc) + if err != nil { + return err + } + return v.translateError(v.bucket.Del(loc)) +} + +// checkRaceWindow returns a non-nil error if trash/loc is, or might +// be, in the race window (i.e., it's not safe to trash loc). +func (v *S3Volume) checkRaceWindow(loc string) error { + resp, err := v.bucket.Head("trash/"+loc, nil) + err = v.translateError(err) + if os.IsNotExist(err) { + // OK, trash/X doesn't exist so we're not in the race + // window return nil + } else if err != nil { + // Error looking up trash/X. We don't know whether + // we're in the race window + return err + } + t, err := v.lastModified(resp) + if err != nil { + // Can't parse timestamp + return err + } + safeWindow := t.Add(theConfig.TrashLifetime.Duration()).Sub(time.Now().Add(time.Duration(v.RaceWindow))) + if safeWindow <= 0 { + // We can't count on "touch trash/X" to prolong + // trash/X's lifetime. The new timestamp might not + // become visible until now+raceWindow, and EmptyTrash + // is allowed to delete trash/X before then. + return fmt.Errorf("same block is already in trash, and safe window ended %s ago", -safeWindow) + } + // trash/X exists, but it won't be eligible for deletion until + // after now+raceWindow, so it's safe to overwrite it. + return nil +} + +// safeCopy calls PutCopy, and checks the response to make sure the +// copy succeeded and updated the timestamp on the destination object +// (PutCopy returns 200 OK if the request was received, even if the +// copy failed). +func (v *S3Volume) safeCopy(dst, src string) error { + resp, err := v.bucket.PutCopy(dst, s3ACL, s3.CopyOptions{ + ContentType: "application/octet-stream", + MetadataDirective: "REPLACE", + }, v.bucket.Name+"/"+src) + err = v.translateError(err) + if err != nil { + return err + } + if t, err := time.Parse(time.RFC3339Nano, resp.LastModified); err != nil { + return fmt.Errorf("PutCopy succeeded but did not return a timestamp: %q: %s", resp.LastModified, err) + } else if time.Now().Sub(t) > maxClockSkew { + return fmt.Errorf("PutCopy succeeded but returned an old timestamp: %q: %s", resp.LastModified, t) } - if !s3UnsafeDelete { - return ErrS3DeleteNotAvailable + return nil +} + +// Get the LastModified header from resp, and parse it as RFC1123 or +// -- if it isn't valid RFC1123 -- as Amazon's variant of RFC1123. +func (v *S3Volume) lastModified(resp *http.Response) (t time.Time, err error) { + s := resp.Header.Get("Last-Modified") + t, err = time.Parse(time.RFC1123, s) + if err != nil && s != "" { + // AWS example is "Sun, 1 Jan 2006 12:00:00 GMT", + // which isn't quite "Sun, 01 Jan 2006 12:00:00 GMT" + // as required by HTTP spec. If it's not a valid HTTP + // header value, it's probably AWS (or s3test) giving + // us a nearly-RFC1123 timestamp. + t, err = time.Parse(nearlyRFC1123, s) } - return v.Bucket.Del(loc) + return } -// TBD +// Untrash moves block from trash back into store func (v *S3Volume) Untrash(loc string) error { - return ErrNotImplemented + err := v.safeCopy(loc, "trash/"+loc) + if err != nil { + return err + } + err = v.bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{}) + return v.translateError(err) } +// Status returns a *VolumeStatus representing the current in-use +// storage capacity and a fake available capacity that doesn't make +// the volume seem full or nearly-full. func (v *S3Volume) Status() *VolumeStatus { return &VolumeStatus{ DeviceNum: 1, @@ -292,15 +507,21 @@ func (v *S3Volume) Status() *VolumeStatus { } } +// String implements fmt.Stringer. func (v *S3Volume) String() string { - return fmt.Sprintf("s3-bucket:%+q", v.Bucket.Name) + return fmt.Sprintf("s3-bucket:%+q", v.bucket.Name) } +// Writable returns false if all future Put, Mtime, and Delete calls +// are expected to fail. func (v *S3Volume) Writable() bool { - return !v.readonly + return !v.ReadOnly } + +// Replication returns the storage redundancy of the underlying +// device. Configured via command line flag. func (v *S3Volume) Replication() int { - return v.replication + return v.S3Replication } var s3KeepBlockRegexp = regexp.MustCompile(`^[0-9a-f]{32}$`) @@ -309,10 +530,57 @@ func (v *S3Volume) isKeepBlock(s string) bool { return s3KeepBlockRegexp.MatchString(s) } +// fixRace(X) is called when "recent/X" exists but "X" doesn't +// exist. If the timestamps on "recent/"+loc and "trash/"+loc indicate +// there was a race between Put and Trash, fixRace recovers from the +// race by Untrashing the block. +func (v *S3Volume) fixRace(loc string) bool { + trash, err := v.bucket.Head("trash/"+loc, nil) + if err != nil { + if !os.IsNotExist(v.translateError(err)) { + log.Printf("error: fixRace: HEAD %q: %s", "trash/"+loc, err) + } + return false + } + trashTime, err := v.lastModified(trash) + if err != nil { + log.Printf("error: fixRace: parse %q: %s", trash.Header.Get("Last-Modified"), err) + return false + } + + recent, err := v.bucket.Head("recent/"+loc, nil) + if err != nil { + log.Printf("error: fixRace: HEAD %q: %s", "recent/"+loc, err) + return false + } + recentTime, err := v.lastModified(recent) + if err != nil { + log.Printf("error: fixRace: parse %q: %s", recent.Header.Get("Last-Modified"), err) + return false + } + + ageWhenTrashed := trashTime.Sub(recentTime) + if ageWhenTrashed >= theConfig.BlobSignatureTTL.Duration() { + // No evidence of a race: block hasn't been written + // since it became eligible for Trash. No fix needed. + return false + } + + log.Printf("notice: fixRace: %q: trashed at %s but touched at %s (age when trashed = %s < %s)", loc, trashTime, recentTime, ageWhenTrashed, theConfig.BlobSignatureTTL) + log.Printf("notice: fixRace: copying %q to %q to recover from race between Put/Touch and Trash", "recent/"+loc, loc) + err = v.safeCopy(loc, "trash/"+loc) + if err != nil { + log.Printf("error: fixRace: %s", err) + return false + } + return true +} + func (v *S3Volume) translateError(err error) error { switch err := err.(type) { case *s3.Error: - if err.StatusCode == http.StatusNotFound && err.Code == "NoSuchKey" { + if (err.StatusCode == http.StatusNotFound && err.Code == "NoSuchKey") || + strings.Contains(err.Error(), "Not Found") { return os.ErrNotExist } // Other 404 errors like NoSuchVersion and @@ -323,8 +591,154 @@ func (v *S3Volume) translateError(err error) error { return err } -// EmptyTrash looks for trashed blocks that exceeded trashLifetime +// EmptyTrash looks for trashed blocks that exceeded TrashLifetime // and deletes them from the volume. -// TBD func (v *S3Volume) EmptyTrash() { + var bytesInTrash, blocksInTrash, bytesDeleted, blocksDeleted int64 + + // Use a merge sort to find matching sets of trash/X and recent/X. + trashL := s3Lister{ + Bucket: v.bucket, + Prefix: "trash/", + PageSize: v.IndexPageSize, + } + // Define "ready to delete" as "...when EmptyTrash started". + startT := time.Now() + for trash := trashL.First(); trash != nil; trash = trashL.Next() { + loc := trash.Key[6:] + if !v.isKeepBlock(loc) { + continue + } + bytesInTrash += trash.Size + blocksInTrash++ + + trashT, err := time.Parse(time.RFC3339, trash.LastModified) + if err != nil { + log.Printf("warning: %s: EmptyTrash: %q: parse %q: %s", v, trash.Key, trash.LastModified, err) + continue + } + recent, err := v.bucket.Head("recent/"+loc, nil) + if err != nil && os.IsNotExist(v.translateError(err)) { + log.Printf("warning: %s: EmptyTrash: found trash marker %q but no %q (%s); calling Untrash", v, trash.Key, "recent/"+loc, err) + err = v.Untrash(loc) + if err != nil { + log.Printf("error: %s: EmptyTrash: Untrash(%q): %s", v, loc, err) + } + continue + } else if err != nil { + log.Printf("warning: %s: EmptyTrash: HEAD %q: %s", v, "recent/"+loc, err) + continue + } + recentT, err := v.lastModified(recent) + if err != nil { + log.Printf("warning: %s: EmptyTrash: %q: parse %q: %s", v, "recent/"+loc, recent.Header.Get("Last-Modified"), err) + continue + } + if trashT.Sub(recentT) < theConfig.BlobSignatureTTL.Duration() { + if age := startT.Sub(recentT); age >= theConfig.BlobSignatureTTL.Duration()-time.Duration(v.RaceWindow) { + // recent/loc is too old to protect + // loc from being Trashed again during + // the raceWindow that starts if we + // delete trash/X now. + // + // Note this means (TrashCheckInterval + // < BlobSignatureTTL - raceWindow) is + // necessary to avoid starvation. + log.Printf("notice: %s: EmptyTrash: detected old race for %q, calling fixRace + Touch", v, loc) + v.fixRace(loc) + v.Touch(loc) + continue + } else if _, err := v.bucket.Head(loc, nil); os.IsNotExist(err) { + log.Printf("notice: %s: EmptyTrash: detected recent race for %q, calling fixRace", v, loc) + v.fixRace(loc) + continue + } else if err != nil { + log.Printf("warning: %s: EmptyTrash: HEAD %q: %s", v, loc, err) + continue + } + } + if startT.Sub(trashT) < theConfig.TrashLifetime.Duration() { + continue + } + err = v.bucket.Del(trash.Key) + if err != nil { + log.Printf("warning: %s: EmptyTrash: deleting %q: %s", v, trash.Key, err) + continue + } + bytesDeleted += trash.Size + blocksDeleted++ + + _, err = v.bucket.Head(loc, nil) + if os.IsNotExist(err) { + err = v.bucket.Del("recent/" + loc) + if err != nil { + log.Printf("warning: %s: EmptyTrash: deleting %q: %s", v, "recent/"+loc, err) + } + } else if err != nil { + log.Printf("warning: %s: EmptyTrash: HEAD %q: %s", v, "recent/"+loc, err) + } + } + if err := trashL.Error(); err != nil { + log.Printf("error: %s: EmptyTrash: lister: %s", v, err) + } + log.Printf("EmptyTrash stats for %v: Deleted %v bytes in %v blocks. Remaining in trash: %v bytes in %v blocks.", v.String(), bytesDeleted, blocksDeleted, bytesInTrash-bytesDeleted, blocksInTrash-blocksDeleted) +} + +type s3Lister struct { + Bucket *s3.Bucket + Prefix string + PageSize int + nextMarker string + buf []s3.Key + err error +} + +// First fetches the first page and returns the first item. It returns +// nil if the response is the empty set or an error occurs. +func (lister *s3Lister) First() *s3.Key { + lister.getPage() + return lister.pop() +} + +// Next returns the next item, fetching the next page if necessary. It +// returns nil if the last available item has already been fetched, or +// an error occurs. +func (lister *s3Lister) Next() *s3.Key { + if len(lister.buf) == 0 && lister.nextMarker != "" { + lister.getPage() + } + return lister.pop() +} + +// Return the most recent error encountered by First or Next. +func (lister *s3Lister) Error() error { + return lister.err +} + +func (lister *s3Lister) getPage() { + resp, err := lister.Bucket.List(lister.Prefix, "", lister.nextMarker, lister.PageSize) + lister.nextMarker = "" + if err != nil { + lister.err = err + return + } + if resp.IsTruncated { + lister.nextMarker = resp.NextMarker + } + lister.buf = make([]s3.Key, 0, len(resp.Contents)) + for _, key := range resp.Contents { + if !strings.HasPrefix(key.Key, lister.Prefix) { + log.Printf("warning: s3Lister: S3 Bucket.List(prefix=%q) returned key %q", lister.Prefix, key.Key) + continue + } + lister.buf = append(lister.buf, key) + } +} + +func (lister *s3Lister) pop() (k *s3.Key) { + if len(lister.buf) > 0 { + k = &lister.buf[0] + lister.buf = lister.buf[1:] + } + return }