聊聊puma的Sender

序

本文主要研究一下puma的Sender

Sender

puma/puma/src/main/java/com/dianping/puma/sender/Sender.java

public interface Sender extends LifeCycle {

    String getName();

    void send(ChangedEvent event, PumaContext context) throws SenderException;
}

• Sender定义了getName、send方法

AbstractSender

puma/puma/src/main/java/com/dianping/puma/sender/AbstractSender.java

public abstract class AbstractSender implements Sender {
    protected static final Logger LOG = LoggerFactory.getLogger(AbstractSender.class);

    private String name;

    private int maxTryTimes = 3;

    private boolean canMissEvent = false;

    private volatile boolean stopped = true;

    private final String MSG_SKIP = "[Miss]Send event failed for %d times. [servername=%s; current binlogfile=%s; current binlogpos=%d; next binlogpos=%d] ";

    private final String MSG_LOOP_FAILED = "[Can't Miss]Send event failed for %d times. [servername=%s; current binlogfile=%s; current binlogpos=%d; next binlogpos=%d] ";

    /**
     * @return the stop
     */
    public boolean isStop() {
        return stopped;
    }

    /**
     * @return the maxTryTimes
     */
    public int getMaxTryTimes() {
        return maxTryTimes;
    }

    /**
     * @param maxTryTimes the maxTryTimes to set
     */
    public void setMaxTryTimes(int maxTryTimes) {
        this.maxTryTimes = maxTryTimes;
    }

    /**
     * @return the canMissEvent
     */
    public boolean isCanMissEvent() {
        return canMissEvent;
    }

    /**
     * @param canMissEvent the canMissEvent to set
     */
    public void setCanMissEvent(boolean canMissEvent) {
        this.canMissEvent = canMissEvent;
    }

    /*
     * (non-Javadoc)
     *
     * @see com.dianping.puma.common.LifeCycle#start()
     */
    @Override
    public void start() {
        stopped = false;
    }

    /*
     * (non-Javadoc)
     *
     * @see com.dianping.puma.common.LifeCycle#stop()
     */
    @Override
    public void stop() {
        stopped = true;
    }

    /*
     * (non-Javadoc)
     *
     * @see com.dianping.puma.sender.Sender#getName()
     */
    @Override
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public void send(ChangedEvent event, PumaContext context) throws SenderException {
        long retryCount = 0;

        while (true) {
            if (isStop()) {
                break;
            }

            try {
                doSend(event, context);
                break;
            } catch (Exception e) {
                LOG.error("Send error!", e);

                if (retryCount++ > maxTryTimes) {
                    if (canMissEvent) {
                        LOG.error(String.format(MSG_SKIP, maxTryTimes, context.getPumaServerName(),
                                context.getBinlogFileName(), context.getBinlogStartPos(), context.getNextBinlogPos()));
                        return;
                    } else {
                        if (retryCount % 100 == 0) {
                            LOG.error(String.format(MSG_LOOP_FAILED, maxTryTimes, context.getPumaServerName(),
                                    context.getBinlogFileName(), context.getBinlogStartPos(), context.getNextBinlogPos()));
                        }
                    }
                }

                try {
                    Thread.sleep(((retryCount % 15) + 1) * 300);
                } catch (InterruptedException e1) {
                    Thread.currentThread().interrupt();
                    throw new SenderException("Interrupted", e1);
                }
            }
        }
    }

    protected abstract void doSend(ChangedEvent event, PumaContext context) throws SenderException;
}

• AbstractSender声明实现了Sender接口，其send方法通过while循环执行doSend(event, context)方法，出现Exception时，在retryCount没有大于maxTryTimes时则sleep((retryCount % 15) + 1) * 300之后再次重试

FileDumpSender

puma/puma/src/main/java/com/dianping/puma/sender/FileDumpSender.java

public class FileDumpSender extends AbstractSender {
    private Map<String, WriteChannel> writeChannels = new ConcurrentHashMap<String, WriteChannel>();

    private ChangedEvent transactionBegin;

    private EventFilterChain storageEventFilterChain;

    @Override
    public void start() {
        super.start();
    }

    @Override
    public void stop() {
        for (WriteChannel channel : writeChannels.values()) {
            channel.stop();
        }
        super.stop();
    }

    @Override
    protected void doSend(ChangedEvent event, PumaContext context) throws SenderException {
        // Storage filter.
        storageEventFilterChain.reset();
        if (!storageEventFilterChain.doNext(event)) {
            return;
        }

        try {
            String database = event.getDatabase();

            if (database != null && database.length() > 0) {
                WriteChannel writeChannel = this.writeChannels.get(database);

                if (writeChannel == null) {
                    writeChannel = buildEventStorage(database);
                    this.writeChannels.put(database, writeChannel);
                }

                boolean isTransactionBegin = false;

                if (event instanceof RowChangedEvent) {
                    isTransactionBegin = ((RowChangedEvent) event).isTransactionBegin();
                }

                if (transactionBegin != null && !isTransactionBegin) {
                    //readChannel.store(transactionBegin);
                    transactionBegin = null;
                }


                writeChannel.append(event);
            } else {
                if (event instanceof RowChangedEvent) {
                    if (((RowChangedEvent) event).isTransactionBegin()) {
                        transactionBegin = event;
                    } else {
                        Cat.logEvent("Puma", "RowChangeEvent-Has-No-Database");
                        LOG.error(String.format("RowChangeEvent[%s] has no database", event.toString()));
                    }
                } else {
                    Cat.logEvent("Puma", "ChangeEvent-Has-No-Database");
                    LOG.error(String.format("ChangeEvent[%s] has no database", event.toString()));
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private WriteChannel buildEventStorage(String database) {
        WriteChannel writeChannel = ChannelFactory.newWriteChannel(database);
        writeChannel.start();
        return writeChannel;
    }

    public void setStorageEventFilterChain(EventFilterChain storageEventFilterChain) {
        this.storageEventFilterChain = storageEventFilterChain;
    }
}

• FileDumpSender继承了AbstractSender，它定义了writeChannels属性，其stop方法会遍历writeChannels，挨个执行channel.stop()；其doSend方法先执行storageEventFilterChain.doNext(event)，返回false的话则直接返回，之后获取或者创建指定database的writeChannel，执行writeChannel.append(event)；对于database为null的则判断是否是RowChangedEvent，是的话，在RowChangedEvent的isTransactionBegin时设置transactionBegin

小结

Sender定义了getName、send方法；AbstractSender声明实现了Sender接口，其send方法通过while循环执行doSend(event, context)方法，出现Exception时，在retryCount没有大于maxTryTimes时则sleep((retryCount % 15) + 1) * 300之后再次重试

doc

• Sender