)
var (
- ErrS3DeleteNotAvailable = fmt.Errorf("delete without -s3-unsafe-delete is not implemented")
+ ErrS3TrashNotAvailable = fmt.Errorf("trash is not possible because -trash-lifetime=0 and -s3-unsafe-delete=false")
s3AccessKeyFile string
s3SecretKeyFile string
s3Endpoint string
s3Replication int
s3UnsafeDelete bool
+ s3RaceWindow time.Duration
s3ACL = s3.Private
)
if flagSerializeIO {
log.Print("Notice: -serialize is not supported by s3-bucket volumes.")
}
- v := NewS3Volume(auth, region, bucketName, flagReadonly, s3Replication)
+ v := NewS3Volume(auth, region, bucketName, s3RaceWindow, flagReadonly, s3Replication)
if err := v.Check(); err != nil {
return err
}
"s3-secret-key-file",
"",
"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",
type S3Volume struct {
*s3.Bucket
+ raceWindow time.Duration
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 {
+func NewS3Volume(auth aws.Auth, region aws.Region, bucket string, raceWindow time.Duration, readonly bool, replication int) *S3Volume {
return &S3Volume{
Bucket: &s3.Bucket{
S3: s3.New(auth, region),
Name: bucket,
},
+ raceWindow: raceWindow,
readonly: readonly,
replication: replication,
indexPageSize: 1000,
return nil
}
+func (v *S3Volume) getReaderWithFixRace(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 {
+ log.Printf("warning: reading %s after successful fixRace: %s", loc, err)
+ err = v.translateError(err)
+ }
+ return
+}
+
func (v *S3Volume) Get(loc string, buf []byte) (int, error) {
- rdr, err := v.Bucket.GetReader(loc)
+ rdr, err := v.getReaderWithFixRace(loc)
if err != nil {
- return 0, v.translateError(err)
+ return 0, err
}
defer rdr.Close()
n, err := io.ReadFull(rdr, buf)
}
func (v *S3Volume) Compare(loc string, expect []byte) error {
- rdr, err := v.Bucket.GetReader(loc)
+ rdr, err := v.getReaderWithFixRace(loc)
if err != nil {
- return v.translateError(err)
+ return err
}
defer rdr.Close()
return v.translateError(compareReaderWithBuf(rdr, expect, loc[:32]))
}
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)
}
func (v *S3Volume) Touch(loc string) error {
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)
}
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)
}
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.UnixNano())
}
- 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
}
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 {
return nil
}
- if !s3UnsafeDelete {
- return ErrS3DeleteNotAvailable
+ if trashLifetime == 0 {
+ if !s3UnsafeDelete {
+ return ErrS3TrashNotAvailable
+ }
+ return v.Bucket.Del(loc)
+ }
+
+ // Make sure we're not in the race window.
+ {
+ 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
+ } else if err != nil {
+ // Error looking up trash/X. Unsafe to proceed
+ // without knowing whether we're in the race
+ // window
+ return err
+ } else if t, err := v.lastModified(resp); err != nil {
+ // Can't parse timestamp
+ return err
+ } else if safeWindow := t.Add(trashLifetime).Sub(time.Now().Add(v.raceWindow)); 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)
+ }
+ }
+
+ err := v.safeCopy("trash/"+loc, loc)
+ if err != nil {
+ return err
+ }
+ return v.translateError(v.Bucket.Del(loc))
+}
+
+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)
}
- return v.Bucket.Del(loc)
+ 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
}
-// TBD
func (v *S3Volume) Untrash(loc string) error {
- return ErrNotImplemented
+ return v.safeCopy(loc, "trash/"+loc)
}
func (v *S3Volume) Status() *VolumeStatus {
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 >= blobSignatureTTL {
+ // 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, 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:
// EmptyTrash looks for trashed blocks that exceeded trashLifetime
// and deletes them from the volume.
-// TBD
func (v *S3Volume) EmptyTrash() {
+ // 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".
+ now := time.Now()
+ for trash := trashL.First(); trash != nil; trash = trashL.Next() {
+ loc := trash.Key[6:]
+ if !v.isKeepBlock(loc) {
+ continue
+ }
+ recent, err := v.Bucket.Head("recent/"+loc, nil)
+ if err != nil {
+ log.Printf("warning: %s: EmptyTrash: cannot delete trash %q with no corresponding recent/* marker", v, trash.Key)
+ continue
+ }
+ trashT, err := time.Parse(time.RFC3339, trash.LastModified)
+ if err != nil {
+ continue
+ }
+ recentT, err := v.lastModified(recent)
+ if err != nil {
+ continue
+ }
+ if trashT.Sub(recentT) < blobSignatureTTL {
+ v.fixRace(loc)
+ continue
+ }
+ if now.Sub(trashT) < trashLifetime {
+ continue
+ }
+ err = v.Bucket.Del(trash.Key)
+ if err != nil {
+ log.Printf("warning: %s: EmptyTrash: deleting %q: %s", v, trash.Key, err)
+ continue
+ }
+ _, 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)
+ }
+}
+
+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
}
projects / arvados.git / commitdiff