add grpc ec shard read

weed/storage/store_ec.go

@@ -89,9 +89,62 @@ func (s *Store) HasEcShard(vid needle.VolumeId) (erasure_coding.EcVolumeShards,
 
 func (s *Store) ReadEcShardNeedle(vid needle.VolumeId, n *needle.Needle) (int, error) {
 	for _, location := range s.Locations {
-		if ecShards, found := location.HasEcShard(vid); found {
-			return ecShards.ReadEcShardNeedle(n)
+		if localEcShards, found := location.HasEcShard(vid); found {
+
+			offset, size, intervals, err := localEcShards.LocateEcShardNeedle(n)
+			if err != nil {
+				return 0, err
+			}
+
+			bytes, err := s.ReadEcShardIntervals(vid, localEcShards, intervals)
+			if err != nil {
+				return 0, fmt.Errorf("ReadEcShardIntervals: %v", err)
+			}
+
+			version := needle.CurrentVersion
+
+			err = n.ReadBytes(bytes, offset.ToAcutalOffset(), size, version)
+			if err != nil {
+				return 0, fmt.Errorf("readbytes: %v", err)
+			}
+
+			return len(bytes), nil
 		}
 	}
 	return 0, fmt.Errorf("ec shard %d not found", vid)
 }
+
+func (s *Store) ReadEcShardIntervals(vid needle.VolumeId, localEcShards erasure_coding.EcVolumeShards, intervals []erasure_coding.Interval) (data []byte, err error) {
+	for i, interval := range intervals {
+		if d, e := s.readOneEcShardInterval(vid, localEcShards, interval); e != nil {
+			return nil, e
+		} else {
+			if i == 0 {
+				data = d
+			} else {
+				data = append(data, d...)
+			}
+		}
+	}
+	return
+}
+
+func (s *Store) readOneEcShardInterval(vid needle.VolumeId, localEcShards erasure_coding.EcVolumeShards, interval erasure_coding.Interval) (data []byte, err error) {
+	shardId, actualOffset := interval.ToShardIdAndOffset(erasure_coding.ErasureCodingLargeBlockSize, erasure_coding.ErasureCodingSmallBlockSize)
+	data = make([]byte, interval.Size)
+	if shard, found := localEcShards.FindEcVolumeShard(shardId); found {
+		if _, err = shard.ReadAt(data, actualOffset); err != nil {
+			return
+		}
+	} else {
+		s.readOneRemoteEcShardInterval(vid, shardId, data, actualOffset)
+	}
+	return
+}
+
+func (s *Store) readOneRemoteEcShardInterval(vid needle.VolumeId, shardId erasure_coding.ShardId, buf []byte, offset int64) (n int, err error) {
+
+
+
+	return
+}