WIP: Add metadata to store record (#1604)

* Add metadata to store record

* Add metadata to cockroach store

* add metadata to store service implementation

* fix breaking cache test

* Test/fix cockroach metadata usage

* fix store memory metadata bug

store/memory/memory.go

@@ -33,9 +33,10 @@ type memoryStore struct {
 	store *cache.Cache
 }
 
-type internalRecord struct {
+type storeRecord struct {
 	key       string
 	value     []byte
+	metadata  map[string]interface{}
 	expiresAt time.Time
 }
 
@@ -56,26 +57,36 @@ func (m *memoryStore) prefix(database, table string) string {
 func (m *memoryStore) get(prefix, key string) (*store.Record, error) {
 	key = m.key(prefix, key)
 
-	var storedRecord *internalRecord
+	var storedRecord *storeRecord
 	r, found := m.store.Get(key)
 	if !found {
 		return nil, store.ErrNotFound
 	}
 
-	storedRecord, ok := r.(*internalRecord)
+	storedRecord, ok := r.(*storeRecord)
 	if !ok {
-		return nil, errors.New("Retrieved a non *internalRecord from the cache")
+		return nil, errors.New("Retrieved a non *storeRecord from the cache")
 	}
 
 	// Copy the record on the way out
 	newRecord := &store.Record{}
 	newRecord.Key = strings.TrimPrefix(storedRecord.key, prefix+"/")
 	newRecord.Value = make([]byte, len(storedRecord.value))
+	newRecord.Metadata = make(map[string]interface{})
+
+	// copy the value into the new record
 	copy(newRecord.Value, storedRecord.value)
+
+	// check if we need to set the expiry
 	if !storedRecord.expiresAt.IsZero() {
 		newRecord.Expiry = time.Until(storedRecord.expiresAt)
 	}
 
+	// copy in the metadata
+	for k, v := range storedRecord.metadata {
+		newRecord.Metadata[k] = v
+	}
+
 	return newRecord, nil
 }
 
@@ -84,15 +95,24 @@ func (m *memoryStore) set(prefix string, r *store.Record) {
 
 	// copy the incoming record and then
 	// convert the expiry in to a hard timestamp
-	i := &internalRecord{}
+	i := &storeRecord{}
 	i.key = r.Key
 	i.value = make([]byte, len(r.Value))
+	i.metadata = make(map[string]interface{})
+
+	// copy the the value
 	copy(i.value, r.Value)
 
+	// set the expiry
 	if r.Expiry != 0 {
 		i.expiresAt = time.Now().Add(r.Expiry)
 	}
 
+	// set the metadata
+	for k, v := range r.Metadata {
+		i.metadata[k] = v
+	}
+
 	m.store.Set(key, i, r.Expiry)
 }
 
@@ -199,6 +219,7 @@ func (m *memoryStore) Write(r *store.Record, opts ...store.WriteOption) error {
 		newRecord := store.Record{}
 		newRecord.Key = r.Key
 		newRecord.Value = make([]byte, len(r.Value))
+		newRecord.Metadata = make(map[string]interface{})
 		copy(newRecord.Value, r.Value)
 		newRecord.Expiry = r.Expiry
 
@@ -208,6 +229,11 @@ func (m *memoryStore) Write(r *store.Record, opts ...store.WriteOption) error {
 		if writeOpts.TTL != 0 {
 			newRecord.Expiry = writeOpts.TTL
 		}
+
+		for k, v := range r.Metadata {
+			newRecord.Metadata[k] = v
+		}
+
 		m.set(prefix, &newRecord)
 		return nil
 	}