kafka CooperativeStickyAssignor 源码

  • 2022-10-20
  • 浏览 (625)

kafka CooperativeStickyAssignor 代码

文件路径:/clients/src/main/java/org/apache/kafka/clients/consumer/CooperativeStickyAssignor.java

/*
 * 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.
 */
package org.apache.kafka.clients.consumer;

import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import org.apache.kafka.clients.consumer.internals.AbstractStickyAssignor;
import org.apache.kafka.common.TopicPartition;
import org.apache.kafka.common.protocol.types.Field;
import org.apache.kafka.common.protocol.types.Schema;
import org.apache.kafka.common.protocol.types.Struct;
import org.apache.kafka.common.protocol.types.Type;

/**
 * A cooperative version of the {@link AbstractStickyAssignor AbstractStickyAssignor}. This follows the same (sticky)
 * assignment logic as {@link StickyAssignor StickyAssignor} but allows for cooperative rebalancing while the
 * {@link StickyAssignor StickyAssignor} follows the eager rebalancing protocol. See
 * {@link ConsumerPartitionAssignor.RebalanceProtocol} for an explanation of the rebalancing protocols.
 * <p>
 * Users should prefer this assignor for newer clusters.
 * <p>
 * To turn on cooperative rebalancing you must set all your consumers to use this {@code PartitionAssignor},
 * or implement a custom one that returns {@code RebalanceProtocol.COOPERATIVE} in
 * {@link CooperativeStickyAssignor#supportedProtocols supportedProtocols()}.
 * <p>
 * IMPORTANT: if upgrading from 2.3 or earlier, you must follow a specific upgrade path in order to safely turn on
 * cooperative rebalancing. See the <a href="https://kafka.apache.org/documentation/#upgrade_240_notable">upgrade guide</a> for details.
 */
public class CooperativeStickyAssignor extends AbstractStickyAssignor {
    public static final String COOPERATIVE_STICKY_ASSIGNOR_NAME = "cooperative-sticky";

    // these schemas are used for preserving useful metadata for the assignment, such as the last stable generation
    private static final String GENERATION_KEY_NAME = "generation";
    private static final Schema COOPERATIVE_STICKY_ASSIGNOR_USER_DATA_V0 = new Schema(
        new Field(GENERATION_KEY_NAME, Type.INT32));

    private int generation = DEFAULT_GENERATION; // consumer group generation

    @Override
    public String name() {
        return COOPERATIVE_STICKY_ASSIGNOR_NAME;
    }

    @Override
    public List<RebalanceProtocol> supportedProtocols() {
        return Arrays.asList(RebalanceProtocol.COOPERATIVE, RebalanceProtocol.EAGER);
    }

    @Override
    public void onAssignment(Assignment assignment, ConsumerGroupMetadata metadata) {
        this.generation = metadata.generationId();
    }

    @Override
    public ByteBuffer subscriptionUserData(Set<String> topics) {
        Struct struct = new Struct(COOPERATIVE_STICKY_ASSIGNOR_USER_DATA_V0);

        struct.set(GENERATION_KEY_NAME, generation);
        ByteBuffer buffer = ByteBuffer.allocate(COOPERATIVE_STICKY_ASSIGNOR_USER_DATA_V0.sizeOf(struct));
        COOPERATIVE_STICKY_ASSIGNOR_USER_DATA_V0.write(buffer, struct);
        buffer.flip();
        return buffer;
    }

    @Override
    protected MemberData memberData(Subscription subscription) {
        ByteBuffer buffer = subscription.userData();
        Optional<Integer> encodedGeneration;
        if (buffer == null) {
            encodedGeneration = Optional.empty();
        } else {
            try {
                Struct struct = COOPERATIVE_STICKY_ASSIGNOR_USER_DATA_V0.read(buffer);
                encodedGeneration = Optional.of(struct.getInt(GENERATION_KEY_NAME));
            } catch (Exception e) {
                encodedGeneration = Optional.of(DEFAULT_GENERATION);
            }
        }
        return new MemberData(subscription.ownedPartitions(), encodedGeneration);
    }

    @Override
    public Map<String, List<TopicPartition>> assign(Map<String, Integer> partitionsPerTopic,
                                                    Map<String, Subscription> subscriptions) {
        Map<String, List<TopicPartition>> assignments = super.assign(partitionsPerTopic, subscriptions);

        Map<TopicPartition, String> partitionsTransferringOwnership = super.partitionsTransferringOwnership == null ?
            computePartitionsTransferringOwnership(subscriptions, assignments) :
            super.partitionsTransferringOwnership;

        adjustAssignment(assignments, partitionsTransferringOwnership);
        return assignments;
    }

    // Following the cooperative rebalancing protocol requires removing partitions that must first be revoked from the assignment
    private void adjustAssignment(Map<String, List<TopicPartition>> assignments,
                                  Map<TopicPartition, String> partitionsTransferringOwnership) {
        for (Map.Entry<TopicPartition, String> partitionEntry : partitionsTransferringOwnership.entrySet()) {
            assignments.get(partitionEntry.getValue()).remove(partitionEntry.getKey());
        }
    }

    private Map<TopicPartition, String> computePartitionsTransferringOwnership(Map<String, Subscription> subscriptions,
                                                                               Map<String, List<TopicPartition>> assignments) {
        Map<TopicPartition, String> allAddedPartitions = new HashMap<>();
        Set<TopicPartition> allRevokedPartitions = new HashSet<>();

        for (final Map.Entry<String, List<TopicPartition>> entry : assignments.entrySet()) {
            String consumer = entry.getKey();

            List<TopicPartition> ownedPartitions = subscriptions.get(consumer).ownedPartitions();
            List<TopicPartition> assignedPartitions = entry.getValue();

            Set<TopicPartition> ownedPartitionsSet = new HashSet<>(ownedPartitions);
            for (TopicPartition tp : assignedPartitions) {
                if (!ownedPartitionsSet.contains(tp))
                    allAddedPartitions.put(tp, consumer);
            }

            Set<TopicPartition> assignedPartitionsSet = new HashSet<>(assignedPartitions);
            for (TopicPartition tp : ownedPartitions) {
                if (!assignedPartitionsSet.contains(tp))
                    allRevokedPartitions.add(tp);
            }
        }

        allAddedPartitions.keySet().retainAll(allRevokedPartitions);
        return allAddedPartitions;
    }
}

相关信息

kafka 源码目录

相关文章

kafka CommitFailedException 源码

kafka Consumer 源码

kafka ConsumerConfig 源码

kafka ConsumerGroupMetadata 源码

kafka ConsumerInterceptor 源码

kafka ConsumerPartitionAssignor 源码

kafka ConsumerRebalanceListener 源码

kafka ConsumerRecord 源码

kafka ConsumerRecords 源码

kafka InvalidOffsetException 源码

0  赞