kafka CommittedOffsetsFile 源码

  • 2022-10-20
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kafka CommittedOffsetsFile 代码


 * 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,
 * See the License for the specific language governing permissions and
 * limitations under the License.

package org.apache.kafka.server.log.remote.metadata.storage;

import org.apache.kafka.common.utils.Utils;
import org.apache.kafka.server.common.CheckpointFile;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.regex.Pattern;

 * This class represents a file containing the committed offsets of remote log metadata partitions.
public class CommittedOffsetsFile {
    private static final int CURRENT_VERSION = 0;
    private static final String SEPARATOR = " ";

    private static final Pattern MINIMUM_ONE_WHITESPACE = Pattern.compile("\\s+");
    private final CheckpointFile<Map.Entry<Integer, Long>> checkpointFile;

    CommittedOffsetsFile(File offsetsFile) throws IOException {
        CheckpointFile.EntryFormatter<Map.Entry<Integer, Long>> formatter = new EntryFormatter();
        checkpointFile = new CheckpointFile<>(offsetsFile, CURRENT_VERSION, formatter);

    private static class EntryFormatter implements CheckpointFile.EntryFormatter<Map.Entry<Integer, Long>> {

        public String toString(Map.Entry<Integer, Long> entry) {
            // Each entry is stored in a new line as <partition-num offset>
            return entry.getKey() + SEPARATOR + entry.getValue();

        public Optional<Map.Entry<Integer, Long>> fromString(String line) {
            String[] strings = MINIMUM_ONE_WHITESPACE.split(line);
            if (strings.length != 2) {
                return Optional.empty();

            try {
                return Optional.of(Utils.mkEntry(Integer.parseInt(strings[0]), Long.parseLong(strings[1])));
            } catch (NumberFormatException e) {
                return Optional.empty();


    public synchronized void writeEntries(Map<Integer, Long> committedOffsets) throws IOException {

    public synchronized Map<Integer, Long> readEntries() throws IOException {
        List<Map.Entry<Integer, Long>> entries = checkpointFile.read();
        Map<Integer, Long> partitionToOffsets = new HashMap<>(entries.size());
        for (Map.Entry<Integer, Long> entry : entries) {
            Long existingValue = partitionToOffsets.put(entry.getKey(), entry.getValue());
            if (existingValue != null) {
                throw new IOException("Multiple entries exist for key: " + entry.getKey());

        return partitionToOffsets;


kafka 源码目录


kafka ConsumerManager 源码

kafka ConsumerTask 源码

kafka FileBasedRemoteLogMetadataCache 源码

kafka ProducerManager 源码

kafka RemoteLogLeaderEpochState 源码

kafka RemoteLogMetadataCache 源码

kafka RemoteLogMetadataSnapshotFile 源码

kafka RemoteLogMetadataTopicPartitioner 源码

kafka RemoteLogSegmentMetadataSnapshot 源码

kafka RemotePartitionMetadataEventHandler 源码

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