/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * These .proto interfaces are private and stable.
 * Please see https://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-common/Compatibility.html
 * for what changes are allowed for a *stable* .proto interface.
 */

// This file contains protocol buffers that are used throughout HDFS -- i.e.
// by the client, server, and data transfer protocols.
syntax = "proto2";
option java_package = "org.apache.hadoop.hdfs.protocol.proto";
option java_outer_classname = "InterDatanodeProtocolProtos";
option java_generic_services = true;
option java_generate_equals_and_hash = true;
package hadoop.hdfs;

import "hdfs.proto";
import "HdfsServer.proto";

/**
 * Block with location information and new generation stamp
 * to be used for recovery.
 */
message InitReplicaRecoveryRequestProto {
  required RecoveringBlockProto block = 1;
}

/**
 * Repica recovery information
 */
message InitReplicaRecoveryResponseProto {
  required bool replicaFound = 1;

  // The following entries are not set if there was no replica found.
  optional ReplicaStateProto state = 2; // State of the replica
  optional BlockProto block = 3;   // block information
}

/**
 * Update replica with new generation stamp and length
 */
message UpdateReplicaUnderRecoveryRequestProto {
  required ExtendedBlockProto block = 1; // Block identifier
  required uint64 recoveryId = 2;        // New genstamp of the replica
  required uint64 newLength = 3;         // New length of the replica
  // New blockId for copy (truncate), default is 0.
  optional uint64 newBlockId = 4 [default = 0];
}

/**
 * Response returns updated block information
 */
message UpdateReplicaUnderRecoveryResponseProto {
  optional string storageUuid = 1; // ID of the storage that stores replica
}

/**
 * Protocol used between datanodes for block recovery.
 *
 * See the request and response for details of rpc call.
 */
service InterDatanodeProtocolService {
  /**
   * Initialize recovery of a replica
   */
  rpc initReplicaRecovery(InitReplicaRecoveryRequestProto)
      returns(InitReplicaRecoveryResponseProto);

  /**
   * Update a replica with new generation stamp and length
   */
  rpc updateReplicaUnderRecovery(UpdateReplicaUnderRecoveryRequestProto)
      returns(UpdateReplicaUnderRecoveryResponseProto);
}
