/**
 * 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 unstable.
 * Please see http://wiki.apache.org/hadoop/Compatibility
 * for what changes are allowed for a *unstable* .proto interface.
 */

option java_package = "org.apache.hadoop.hdds.protocol.proto";
option java_outer_classname = "ScmBlockLocationProtocolProtos";
option java_generic_services = true;
option java_generate_equals_and_hash = true;
package hadoop.hdds;

import "hdfs.proto";
import "hdds.proto";


// SCM Block protocol
/**
 * keys - batch of block keys to find
 */
message GetScmBlockLocationsRequestProto {
  repeated string keys = 1;
}

/**
 * locatedBlocks - for each requested hash, nodes that currently host the
 *     container for that object key hash
 */
message GetScmBlockLocationsResponseProto {
  repeated ScmLocatedBlockProto locatedBlocks = 1;
}

/**
 * Holds the nodes that currently host the blocks for a key.
 */
message ScmLocatedBlockProto {
  required string key = 1;
  required hadoop.hdds.Pipeline pipeline = 2;
}

/**
* Request send to SCM asking allocate block of specified size.
*/
message AllocateScmBlockRequestProto {
  required uint64 size = 1;
  required ReplicationType type = 2;
  required hadoop.hdds.ReplicationFactor factor = 3;
  required string owner = 4;

}

/**
 * A delete key request sent by KSM to SCM, it contains
 * multiple number of keys (and their blocks).
 */
message DeleteScmKeyBlocksRequestProto {
  repeated KeyBlocks keyBlocks = 1;
}

/**
 * A object key and all its associated blocks.
 * We need to encapsulate object key name plus the blocks in this potocol
 * because SCM needs to response KSM with the keys it has deleted.
 * If the response only contains blocks, it will be very expensive for
 * KSM to figure out what keys have been deleted.
 */
message KeyBlocks {
  required string key = 1;
  repeated string blocks = 2;
}

/**
 * A delete key response from SCM to KSM, it contains multiple child-results.
 * Each child-result represents a key deletion result, only if all blocks of
 * a key are successfully deleted, this key result is considered as succeed.
 */
message DeleteScmKeyBlocksResponseProto {
  repeated DeleteKeyBlocksResultProto results = 1;
}

/**
 * A key deletion result. It contains all the block deletion results.
 */
message DeleteKeyBlocksResultProto {
  required string objectKey = 1;
  repeated DeleteScmBlockResult blockResults = 2;
}

message DeleteScmBlockResult {
  enum Result {
    success = 1;
    chillMode = 2;
    errorNotFound = 3;
    unknownFailure = 4;
  }
  required Result result = 1;
  required string key = 2;
}

/**
 * Reply from SCM indicating that the container.
 */
message AllocateScmBlockResponseProto {
  enum Error {
    success = 1;
    errorNotEnoughSpace = 2;
    errorSizeTooBig = 3;
    unknownFailure = 4;
  }
  required Error errorCode = 1;
  required string key = 2;
  required hadoop.hdds.Pipeline pipeline = 3;
  required bool createContainer = 4;
  optional string errorMessage = 5;
}

/**
 * Protocol used from KeySpaceManager to StorageContainerManager.
 * See request and response messages for details of the RPC calls.
 */
service ScmBlockLocationProtocolService {

  /**
   * Find the set of nodes that currently host the block, as
   * identified by the key.  This method supports batch lookup by
   * passing multiple keys.
   */
  rpc getScmBlockLocations(GetScmBlockLocationsRequestProto)
      returns (GetScmBlockLocationsResponseProto);

  /**
   * Creates a block entry in SCM.
   */
  rpc allocateScmBlock(AllocateScmBlockRequestProto)
      returns (AllocateScmBlockResponseProto);

  /**
   * Deletes blocks for a set of object keys from SCM.
   */
  rpc deleteScmKeyBlocks(DeleteScmKeyBlocksRequestProto)
      returns (DeleteScmKeyBlocksResponseProto);

  /**
   * Gets the scmInfo from SCM.
   */
  rpc getScmInfo(hadoop.hdds.GetScmInfoRequestProto)
      returns (hadoop.hdds.GetScmInfoRespsonseProto);
}