Talk about binlogconnector replicator's work

order

This paper focuses on the work of binlogconnector replicator

StoppableTask

maxwell-1.25.1/src/main/java/com/zendesk/maxwell/util/StoppableTask.java

public interface StoppableTask {
	void requestStop() throws Exception;
	void awaitStop(Long timeout) throws TimeoutException;
}
  • The StoppableTask interface defines the requestStop and awaitStop methods

RunLoopProcess

maxwell-1.25.1/src/main/java/com/zendesk/maxwell/util/RunLoopProcess.java

abstract public class RunLoopProcess implements StoppableTask {
	protected volatile StoppableTaskState taskState;
	private Thread thread;

	public RunLoopProcess() {
		this.taskState = new StoppableTaskState(this.getClass().getName());
	}

	public void requestStop() {
		this.taskState.requestStop();

		interrupt();
	}

	public void interrupt() {
		if ( this.thread != null )
			this.thread.interrupt();
	}

	public void awaitStop(Long timeout) throws TimeoutException {
		this.taskState.awaitStop(thread, timeout);
	}

	public void runLoop() throws Exception {
		this.thread = Thread.currentThread();
		this.beforeStart();

		try {
			while (this.taskState.isRunning()) {
				work();
			}
		} finally {
			this.beforeStop();
			this.taskState.stopped();
		}
	}

	protected abstract void work() throws Exception;
	protected void beforeStart() throws Exception { }
	protected void beforeStop() throws Exception { }
}
  • RunLoopProcess implements the StoppableTask interface. Its runLoop method will execute the work() method through the while loop until taskState.isRunning() is false

BinlogConnectorReplicator

maxwell-1.25.1/src/main/java/com/zendesk/maxwell/replication/BinlogConnectorReplicator.java

public class BinlogConnectorReplicator extends RunLoopProcess implements Replicator {

	//......

	public void work() throws Exception {
		RowMap row = null;
		try {
			row = getRow();
		} catch ( InterruptedException e ) {
		}

		if ( row == null )
			return;

		rowCounter.inc();
		rowMeter.mark();

		if ( scripting != null && !isMaxwellRow(row))
			scripting.invoke(row);

		processRow(row);
	}

	protected void processRow(RowMap row) throws Exception {
		if ( row instanceof HeartbeatRowMap) {
			producer.push(row);
			if (stopAtHeartbeat != null) {
				long thisHeartbeat = row.getPosition().getLastHeartbeatRead();
				if (thisHeartbeat >= stopAtHeartbeat) {
					LOGGER.info("received final heartbeat " + thisHeartbeat + "; stopping replicator");
					// terminate runLoop
					this.taskState.stopped();
				}
			}
		} else if ( !shouldSkipRow(row) )
			producer.push(row);
	}

	//......

}
  • BinlogConnectorReplicator implements the RunLoopProcess interface. Its work method obtains the RowMap through getRow(). If it is not null, it executes the processRow(row) method; the processRow method executes producer.push(row)

AbstractProducer

maxwell-1.25.1/src/main/java/com/zendesk/maxwell/producer/AbstractProducer.java

public abstract class AbstractProducer {
	protected final MaxwellContext context;
	protected final MaxwellOutputConfig outputConfig;
	protected final Counter succeededMessageCount;
	protected final Meter succeededMessageMeter;
	protected final Counter failedMessageCount;
	protected final Meter failedMessageMeter;
	protected final Timer messagePublishTimer;
	protected final Timer messageLatencyTimer;
	protected final Counter messageLatencySloViolationCount;

	public AbstractProducer(MaxwellContext context) {
		this.context = context;
		this.outputConfig = context.getConfig().outputConfig;

		Metrics metrics = context.getMetrics();
		MetricRegistry metricRegistry = metrics.getRegistry();

		this.succeededMessageCount = metricRegistry.counter(metrics.metricName("messages", "succeeded"));
		this.succeededMessageMeter = metricRegistry.meter(metrics.metricName("messages", "succeeded", "meter"));
		this.failedMessageCount = metricRegistry.counter(metrics.metricName("messages", "failed"));
		this.failedMessageMeter = metricRegistry.meter(metrics.metricName("messages", "failed", "meter"));
		this.messagePublishTimer = metricRegistry.timer(metrics.metricName("message", "publish", "time"));
		this.messageLatencyTimer = metricRegistry.timer(metrics.metricName("message", "publish", "age"));
		this.messageLatencySloViolationCount = metricRegistry.counter(metrics.metricName("message", "publish", "age", "slo_violation"));
	}

	abstract public void push(RowMap r) throws Exception;

	public StoppableTask getStoppableTask() {
		return null;
	}

	public Meter getFailedMessageMeter() {
		return this.failedMessageMeter;
	}

	public MaxwellDiagnostic getDiagnostic() {
		return null;
	}
}
  • AbstractProducer defines the push abstract method for subclass implementation

StdoutProducer

maxwell-1.25.1/src/main/java/com/zendesk/maxwell/producer/StdoutProducer.java

public class StdoutProducer extends AbstractProducer {
	public StdoutProducer(MaxwellContext context) {
		super(context);
	}

	@Override
	public void push(RowMap r) throws Exception {
		String output = r.toJSON(outputConfig);

		if ( output != null && r.shouldOutput(outputConfig) )
			System.out.println(output);

		this.context.setPosition(r);
	}
}
  • StdoutProducer inherits AbstractProducer, and its push method executes System.out.println(output) and context.setPosition(r)

Summary

The StoppableTask interface defines the requestStop and awaitStop methods; the RunLoopProcess implements the StoppableTask interface, and its runLoop method will execute the work() method through the while loop until taskState.isRunning() is false; the BinlogConnectorReplicator implements the RunLoopProcess interface, and its work method obtains the RowMap through getRow(). If it is not null, the processRow(row) method is executed ; processRow method executes producer.push(row)

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Tags: Programming Java

Posted on Mon, 04 May 2020 03:27:52 -0400 by riddhi