clients/src/main/resources/common/message/ConsumerProtocolSubscription.json

// 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.

{
  "type": "data",
  "name": "ConsumerProtocolSubscription",
  // Subscription part of the Consumer Protocol.
  //
  // The current implementation assumes that future versions will not break compatibility. When
  // it encounters a newer version, it parses it using the current format. This basically means
  // that new versions cannot remove or reorder any of the existing fields.

  // Version 1 added the "OwnedPartitions" field to allow assigner know what partitions each member owned
  // Version 2 added a new field "GenerationId" to indicate if the member has out-of-date ownedPartitions.
  // Version 3 adds rack id to enable rack-aware assignment.
  "validVersions": "0-3",
  "flexibleVersions": "none",
  "fields": [
    { "name": "Topics", "type": "[]string", "versions": "0+",
      "about": "The topics that the member wants to consume."},
    { "name": "UserData", "type": "bytes", "versions": "0+", "nullableVersions": "0+",
      "default": "null", "zeroCopy": true,
      "about": "User data that will be passed back to the consumer."},
    { "name": "OwnedPartitions", "type": "[]TopicPartition", "versions": "1+", "ignorable": true,
      "about": "The partitions that the member owns.", "fields": [
        { "name": "Topic", "type": "string", "mapKey": true, "versions": "1+", "entityType": "topicName",
          "about": "The topic name."},
        { "name": "Partitions", "type": "[]int32", "versions": "1+",
          "about": "The partition ids."}
      ]
    },
    { "name": "GenerationId", "type": "int32", "versions": "2+", "default": "-1", "ignorable": true,
      "about": "The generation id of the member."},
    { "name": "RackId", "type": "string", "versions": "3+", "nullableVersions": "3+", "default": "null", "ignorable": true,
      "about": "The rack id of the member."}
  ]
}