refactor(storage): refactor storage into a single ImageStore (#1656)

unified both local and s3 ImageStore logic into a single ImageStore
added a new driver interface for common file/dirs manipulations
to be implemented by different storage types

refactor(gc): drop umoci dependency, implemented internal gc

added retentionDelay config option that specifies
the garbage collect delay for images without tags

this will also clean manifests which are part of an index image
(multiarch) that no longer exist.

fix(dedupe): skip blobs under .sync/ directory

if startup dedupe is running while also syncing is running
ignore blobs under sync's temporary storage

fix(storage): do not allow image indexes modifications

when deleting a manifest verify that it is not part of a multiarch image
and throw a MethodNotAllowed error to the client if it is.
we don't want to modify multiarch images

Signed-off-by: Petu Eusebiu <peusebiu@cisco.com>

pkg/api/config/config.go

@@ -23,15 +23,17 @@ var (
 )
 
 type StorageConfig struct {
-	RootDirectory string
-	Dedupe        bool
-	RemoteCache   bool
-	GC            bool
-	Commit        bool
-	GCDelay       time.Duration
-	GCInterval    time.Duration
-	StorageDriver map[string]interface{} `mapstructure:",omitempty"`
-	CacheDriver   map[string]interface{} `mapstructure:",omitempty"`
+	RootDirectory               string
+	Dedupe                      bool
+	RemoteCache                 bool
+	GC                          bool
+	Commit                      bool
+	GCDelay                     time.Duration
+	GCInterval                  time.Duration
+	GCReferrers                 bool
+	UntaggedImageRetentionDelay time.Duration
+	StorageDriver               map[string]interface{} `mapstructure:",omitempty"`
+	CacheDriver                 map[string]interface{} `mapstructure:",omitempty"`
 }
 
 type TLSConfig struct {
@@ -188,8 +190,9 @@ func New() *Config {
 		BinaryType:      BinaryType,
 		Storage: GlobalStorageConfig{
 			StorageConfig: StorageConfig{
-				GC: true, GCDelay: storageConstants.DefaultGCDelay,
-				GCInterval: storageConstants.DefaultGCInterval, Dedupe: true,
+				GC: true, GCReferrers: true, GCDelay: storageConstants.DefaultGCDelay,
+				UntaggedImageRetentionDelay: storageConstants.DefaultUntaggedImgeRetentionDelay,
+				GCInterval:                  storageConstants.DefaultGCInterval, Dedupe: true,
 			},
 		},
 		HTTP: HTTPConfig{Address: "127.0.0.1", Port: "8080", Auth: &AuthConfig{FailDelay: 0}},