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Refactor s3 dedupe

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Under digest bucket create 2 buckets, one for storing origin blob
and one for storing deduped blobs.

PutBlob() - puts an origin blob in both buckets
          - puts a deduped blob in deduped bucket
GetBlob() - returns blobs only from origin bucket
DeleteBlob() - deletes an origin blob from both buckets
             and moves one deduped blob into origin bucket
             - deletes a deduped blob from deduped bucket

[storage] When deleting an origin blob, next time we GetBlob() we get a
deduped blob with no content and we will move the content from
the deleted origin blob to it (inside s3.go).

Signed-off-by: Petu Eusebiu <peusebiu@cisco.com>
This commit is contained in:
Petu Eusebiu 2022-09-08 18:07:00 +03:00 • committed by Ramkumar Chinchani
parent f3faae0e09
commit 7912b6a3fb
2 changed files with 126 additions and 50 deletions
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148
pkg/storage/cache.go
View file

@ -12,11 +12,15 @@ import (
)
const (
BlobsCache = "blobs"
// global bucket.
BlobsCache = "blobs"
// bucket where we store all blobs from storage(deduped blobs + original blob).
DedupedBucket = "deduped"
/* bucket where we store only the original/source blob (used by s3 to know which is the blob with content)
it should contain only one blob, this is the only place from which we'll get blobs. */
OriginBucket = "origin"
DBExtensionName = ".db"
dbCacheLockCheckTimeout = 10 * time.Second
// always mark the first key inserted in the BlobsCache with a value.
firstKeyValue = "first"
)
type Cache struct {
@ -26,6 +30,11 @@ type Cache struct {
useRelPaths bool // weather or not to use relative paths, should be true for filesystem and false for s3
}
// Blob is a blob record.
type Blob struct {
Path string
}
func NewCache(rootDir string, name string, useRelPaths bool, log zlog.Logger) *Cache {
dbPath := path.Join(rootDir, name+DBExtensionName)
dbOpts := &bbolt.Options{
@ -85,28 +94,46 @@ func (c *Cache) PutBlob(digest, path string) error {
return err
}
var value string
bucket, err := root.CreateBucketIfNotExists([]byte(digest))
if err != nil {
// this is a serious failure
c.log.Error().Err(err).Str("bucket", digest).Msg("unable to create a bucket")
bucket := root.Bucket([]byte(digest))
if bucket == nil {
/* mark first key in bucket
in the context of s3 we need to know which blob is real
and we know that the first one is always the real, so mark them.
*/
value = firstKeyValue
bucket, err = root.CreateBucket([]byte(digest))
return err
}
// create nested deduped bucket where we store all the deduped blobs + original blob
deduped, err := bucket.CreateBucketIfNotExists([]byte(DedupedBucket))
if err != nil {
// this is a serious failure
c.log.Error().Err(err).Str("bucket", DedupedBucket).Msg("unable to create a bucket")
return err
}
if err := deduped.Put([]byte(path), nil); err != nil {
c.log.Error().Err(err).Str("bucket", DedupedBucket).Str("value", path).Msg("unable to put record")
return err
}
// create origin bucket and insert only the original blob
origin := bucket.Bucket([]byte(OriginBucket))
if origin == nil {
// if the bucket doesn't exist yet then 'path' is the original blob
origin, err := bucket.CreateBucket([]byte(OriginBucket))
if err != nil {
// this is a serious failure
c.log.Error().Err(err).Str("bucket", digest).Msg("unable to create a bucket")
c.log.Error().Err(err).Str("bucket", OriginBucket).Msg("unable to create a bucket")
return err
}
}
if err := bucket.Put([]byte(path), []byte(value)); err != nil {
c.log.Error().Err(err).Str("bucket", digest).Str("value", path).Msg("unable to put record")
if err := origin.Put([]byte(path), nil); err != nil {
c.log.Error().Err(err).Str("bucket", OriginBucket).Str("value", path).Msg("unable to put record")
return err
return err
}
}
return nil
@ -130,22 +157,10 @@ func (c *Cache) GetBlob(digest string) (string, error) {
return err
}
b := root.Bucket([]byte(digest))
if b != nil {
if err := b.ForEach(func(k, v []byte) error {
// always return the key with 'first' value
if string(v) == firstKeyValue {
blobPath.WriteString(string(k))
return nil
}
return nil
}); err != nil {
c.log.Error().Err(err).Msg("unable to access digest bucket")
return err
}
bucket := root.Bucket([]byte(digest))
if bucket != nil {
origin := bucket.Bucket([]byte(OriginBucket))
blobPath.WriteString(string(c.getOne(origin)))
return nil
}
@ -169,12 +184,17 @@ func (c *Cache) HasBlob(digest, blob string) bool {
return err
}
b := root.Bucket([]byte(digest))
if b == nil {
bucket := root.Bucket([]byte(digest))
if bucket == nil {
return errors.ErrCacheMiss
}
if b.Get([]byte(blob)) == nil {
origin := bucket.Bucket([]byte(OriginBucket))
if origin == nil {
return errors.ErrCacheMiss
}
if origin.Get([]byte(blob)) == nil {
return errors.ErrCacheMiss
}
@ -186,6 +206,17 @@ func (c *Cache) HasBlob(digest, blob string) bool {
return true
}
func (c *Cache) getOne(bucket *bbolt.Bucket) []byte {
if bucket != nil {
cursor := bucket.Cursor()
k, _ := cursor.First()
return k
}
return nil
}
func (c *Cache) DeleteBlob(digest, path string) error {
// use only relative (to rootDir) paths on blobs
var err error
@ -211,28 +242,45 @@ func (c *Cache) DeleteBlob(digest, path string) error {
return errors.ErrCacheMiss
}
value := bucket.Get([]byte(path))
deduped := bucket.Bucket([]byte(DedupedBucket))
if deduped == nil {
return errors.ErrCacheMiss
}
if err := bucket.Delete([]byte(path)); err != nil {
c.log.Error().Err(err).Str("digest", digest).Str("path", path).Msg("unable to delete")
if err := deduped.Delete([]byte(path)); err != nil {
c.log.Error().Err(err).Str("digest", digest).Str("bucket", DedupedBucket).Str("path", path).Msg("unable to delete")
return err
}
cur := bucket.Cursor()
origin := bucket.Bucket([]byte(OriginBucket))
if origin != nil {
originBlob := c.getOne(origin)
if originBlob != nil {
if err := origin.Delete([]byte(path)); err != nil {
c.log.Error().Err(err).Str("digest", digest).Str("bucket", OriginBucket).Str("path", path).Msg("unable to delete")
key, _ := cur.First()
if key == nil {
return err
}
// move next candidate to origin bucket, next GetKey will return this one and storage will move the content here
dedupedBlob := c.getOne(deduped)
if dedupedBlob != nil {
if err := origin.Put(dedupedBlob, nil); err != nil {
c.log.Error().Err(err).Str("digest", digest).Str("bucket", OriginBucket).Str("path", path).Msg("unable to put")
return err
}
}
}
}
// if no key in origin bucket then digest bucket is empty, remove it
k := c.getOne(origin)
if k == nil {
c.log.Debug().Str("digest", digest).Str("path", path).Msg("deleting empty bucket")
if err := root.DeleteBucket([]byte(digest)); err != nil {
c.log.Error().Err(err).Str("digest", digest).Str("path", path).Msg("unable to delete")
return err
}
// if deleted key has value 'first' then move this value to the next key
} else if string(value) == firstKeyValue {
if err := bucket.Put(key, value); err != nil {
c.log.Error().Err(err).Str("bucket", digest).Str("value", path).Msg("unable to put record")
c.log.Error().Err(err).Str("digest", digest).Str("bucket", digest).Str("path", path).Msg("unable to delete")
return err
}

28
pkg/storage/local_test.go
View file

@ -1056,6 +1056,34 @@ func TestDedupeLinks(t *testing.T) {
fi2, err := os.Stat(path.Join(dir, "dedupe2", "blobs", "sha256", blobDigest2))
So(err, ShouldBeNil)
So(os.SameFile(fi1, fi2), ShouldBeTrue)
Convey("storage and cache inconsistency", func() {
// delete blobs
err = os.Remove(path.Join(dir, "dedupe1", "blobs", "sha256", blobDigest1))
So(err, ShouldBeNil)
err := os.Remove(path.Join(dir, "dedupe2", "blobs", "sha256", blobDigest2))
So(err, ShouldBeNil)
// now cache is inconsistent with storage (blobs present in cache but not in storage)
upload, err = imgStore.NewBlobUpload("dedupe3")
So(err, ShouldBeNil)
So(upload, ShouldNotBeEmpty)
content = []byte("test-data3")
buf = bytes.NewBuffer(content)
buflen = buf.Len()
digest = godigest.FromBytes(content)
blob, err = imgStore.PutBlobChunkStreamed("dedupe3", upload, buf)
So(err, ShouldBeNil)
So(blob, ShouldEqual, buflen)
blobDigest2 := strings.Split(digest.String(), ":")[1]
So(blobDigest2, ShouldNotBeEmpty)
err = imgStore.FinishBlobUpload("dedupe3", upload, buf, digest.String())
So(err, ShouldBeNil)
So(blob, ShouldEqual, buflen)
})
})
}