kafka VerifiableSourceTask 源码

kafka VerifiableSourceTask 代码

文件路径：/connect/runtime/src/main/java/org/apache/kafka/connect/tools/VerifiableSourceTask.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.connect.tools;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.kafka.connect.data.SchemaBuilder;
import org.apache.kafka.connect.data.Struct;
import org.apache.kafka.tools.ThroughputThrottler;
import org.apache.kafka.clients.producer.RecordMetadata;
import org.apache.kafka.connect.data.Schema;
import org.apache.kafka.connect.errors.ConnectException;
import org.apache.kafka.connect.source.SourceRecord;
import org.apache.kafka.connect.source.SourceTask;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Stream;

/**
 * A connector primarily intended for system tests. The connector simply generates as many tasks as requested. The
 * tasks print metadata in the form of JSON to stdout for each message generated, making externally visible which
 * messages have been sent. Each message is also assigned a unique, increasing seqno that is passed to Kafka Connect; when
 * tasks are started on new nodes, this seqno is used to resume where the task previously left off, allowing for
 * testing of distributed Kafka Connect.
 *
 * If logging is left enabled, log output on stdout can be easily ignored by checking whether a given line is valid JSON.
 */
public class VerifiableSourceTask extends SourceTask {
    private static final Logger log = LoggerFactory.getLogger(VerifiableSourceTask.class);

    public static final String NAME_CONFIG = "name";
    public static final String ID_CONFIG = "id";
    public static final String TOPIC_CONFIG = "topic";
    public static final String THROUGHPUT_CONFIG = "throughput";
    public static final String COMPLETE_RECORD_DATA_CONFIG = "complete.record.data";

    private static final String ID_FIELD = "id";
    private static final String SEQNO_FIELD = "seqno";

    private static final ObjectMapper JSON_SERDE = new ObjectMapper();

    private String name; // Connector name
    private int id; // Task ID
    private String topic;
    private Map<String, Integer> partition;
    private long startingSeqno;
    private long seqno;
    private ThroughputThrottler throttler;
    private boolean completeRecordData;

    private static final Schema COMPLETE_VALUE_SCHEMA = SchemaBuilder.struct()
        .field("name", Schema.STRING_SCHEMA)
        .field("task", Schema.INT32_SCHEMA)
        .field("topic", Schema.STRING_SCHEMA)
        .field("time_ms", Schema.INT64_SCHEMA)
        .field("seqno", Schema.INT64_SCHEMA)
        .build();

    @Override
    public String version() {
        return new VerifiableSourceConnector().version();
    }

    @Override
    public void start(Map<String, String> props) {
        final long throughput;
        try {
            name = props.get(NAME_CONFIG);
            id = Integer.parseInt(props.get(ID_CONFIG));
            topic = props.get(TOPIC_CONFIG);
            throughput = Long.parseLong(props.get(THROUGHPUT_CONFIG));
        } catch (NumberFormatException e) {
            throw new ConnectException("Invalid VerifiableSourceTask configuration", e);
        }

        partition = Collections.singletonMap(ID_FIELD, id);
        Map<String, Object> previousOffset = this.context.offsetStorageReader().offset(partition);
        if (previousOffset != null)
            seqno = (Long) previousOffset.get(SEQNO_FIELD) + 1;
        else
            seqno = 0;
        startingSeqno = seqno;
        throttler = new ThroughputThrottler(throughput, System.currentTimeMillis());
        completeRecordData = "true".equalsIgnoreCase(props.get(COMPLETE_RECORD_DATA_CONFIG));

        log.info("Started VerifiableSourceTask {}-{} producing to topic {} resuming from seqno {}", name, id, topic, startingSeqno);
    }

    @Override
    public List<SourceRecord> poll() {
        long sendStartMs = System.currentTimeMillis();
        if (throttler.shouldThrottle(seqno - startingSeqno, sendStartMs))
            throttler.throttle();

        long nowMs = System.currentTimeMillis();

        Map<String, Object> data = new HashMap<>();
        data.put("name", name);
        data.put("task", id);
        data.put("topic", this.topic);
        data.put("time_ms", nowMs);
        data.put("seqno", seqno);
        String dataJson;
        try {
            dataJson = JSON_SERDE.writeValueAsString(data);
        } catch (JsonProcessingException e) {
            dataJson = "Bad data can't be written as json: " + e.getMessage();
        }
        System.out.println(dataJson);

        Map<String, Long> ccOffset = Collections.singletonMap(SEQNO_FIELD, seqno);
        Schema valueSchema = completeRecordData ? COMPLETE_VALUE_SCHEMA : Schema.INT64_SCHEMA;
        Object value = completeRecordData ? completeValue(data) : seqno;
        SourceRecord srcRecord = new SourceRecord(partition, ccOffset, topic, Schema.INT32_SCHEMA, id, valueSchema, value);
        List<SourceRecord> result = Collections.singletonList(srcRecord);
        seqno++;
        return result;
    }

    @Override
    public void commitRecord(SourceRecord record, RecordMetadata metadata) {
        Map<String, Object> data = new HashMap<>();
        data.put("name", name);
        data.put("task", id);
        data.put("topic", this.topic);
        data.put("time_ms", System.currentTimeMillis());
        data.put("seqno", record.value());
        data.put("committed", true);

        String dataJson;
        try {
            dataJson = JSON_SERDE.writeValueAsString(data);
        } catch (JsonProcessingException e) {
            dataJson = "Bad data can't be written as json: " + e.getMessage();
        }
        System.out.println(dataJson);
    }

    @Override
    public void stop() {
        if (throttler != null)
            throttler.wakeup();
    }

    private Object completeValue(Map<String, Object> data) {
        Struct result = new Struct(COMPLETE_VALUE_SCHEMA);
        Stream.of("name", "task", "topic", "time_ms", "seqno").forEach(
            field -> result.put(field, data.get(field))
        );
        return result;
    }
}

相关信息

kafka 源码目录

相关文章

kafka MockConnector 源码

kafka MockSinkConnector 源码

kafka MockSinkTask 源码

kafka MockSourceConnector 源码

kafka MockSourceTask 源码

kafka PredicateDoc 源码

kafka SchemaSourceConnector 源码

kafka SchemaSourceTask 源码

kafka TransformationDoc 源码

kafka VerifiableSinkConnector 源码