聊聊rocketmq的RequestTask

序

本文主要研究一下rocketmq的RequestTask

RequestTask

org/apache/rocketmq/remoting/netty/RequestTask.java

public class RequestTask implements Runnable {
    private final Runnable runnable;
    private final long createTimestamp = System.currentTimeMillis();
    private final Channel channel;
    private final RemotingCommand request;
    private boolean stopRun = false;

    public RequestTask(final Runnable runnable, final Channel channel, final RemotingCommand request) {
        this.runnable = runnable;
        this.channel = channel;
        this.request = request;
    }

    @Override
    public int hashCode() {
        int result = runnable != null ? runnable.hashCode() : 0;
        result = 31 * result + (int) (getCreateTimestamp() ^ (getCreateTimestamp() >>> 32));
        result = 31 * result + (channel != null ? channel.hashCode() : 0);
        result = 31 * result + (request != null ? request.hashCode() : 0);
        result = 31 * result + (isStopRun() ? 1 : 0);
        return result;
    }

    @Override
    public boolean equals(final Object o) {
        if (this == o)
            return true;
        if (!(o instanceof RequestTask))
            return false;

        final RequestTask that = (RequestTask) o;

        if (getCreateTimestamp() != that.getCreateTimestamp())
            return false;
        if (isStopRun() != that.isStopRun())
            return false;
        if (channel != null ? !channel.equals(that.channel) : that.channel != null)
            return false;
        return request != null ? request.getOpaque() == that.request.getOpaque() : that.request == null;

    }

    public long getCreateTimestamp() {
        return createTimestamp;
    }

    public boolean isStopRun() {
        return stopRun;
    }

    public void setStopRun(final boolean stopRun) {
        this.stopRun = stopRun;
    }

    @Override
    public void run() {
        if (!this.stopRun)
            this.runnable.run();
    }

    public void returnResponse(int code, String remark) {
        final RemotingCommand response = RemotingCommand.createResponseCommand(code, remark);
        response.setOpaque(request.getOpaque());
        this.channel.writeAndFlush(response);
    }
}

• 里头有一个runnable、channel以及remotingCommand

NettyRemotingAbstract.processRequestCommand

org/apache/rocketmq/remoting/netty/NettyRemotingAbstract.java

    /**
     * This container holds all processors per request code, aka, for each incoming request, we may look up the
     * responding processor in this map to handle the request.
     */
    protected final HashMap<Integer/* request code */, Pair<NettyRequestProcessor, ExecutorService>> processorTable =
        new HashMap<Integer, Pair<NettyRequestProcessor, ExecutorService>>(64);

    //......

    /**
     * Process incoming request command issued by remote peer.
     *
     * @param ctx channel handler context.
     * @param cmd request command.
     */
    public void processRequestCommand(final ChannelHandlerContext ctx, final RemotingCommand cmd) {
        final Pair<NettyRequestProcessor, ExecutorService> matched = this.processorTable.get(cmd.getCode());
        final Pair<NettyRequestProcessor, ExecutorService> pair = null == matched ? this.defaultRequestProcessor : matched;
        final int opaque = cmd.getOpaque();

        if (pair != null) {
            Runnable run = new Runnable() {
                @Override
                public void run() {
                    try {
                        RPCHook rpcHook = NettyRemotingAbstract.this.getRPCHook();
                        if (rpcHook != null) {
                            rpcHook.doBeforeRequest(RemotingHelper.parseChannelRemoteAddr(ctx.channel()), cmd);
                        }

                        final RemotingCommand response = pair.getObject1().processRequest(ctx, cmd);
                        if (rpcHook != null) {
                            rpcHook.doAfterResponse(RemotingHelper.parseChannelRemoteAddr(ctx.channel()), cmd, response);
                        }

                        if (!cmd.isOnewayRPC()) {
                            if (response != null) {
                                response.setOpaque(opaque);
                                response.markResponseType();
                                try {
                                    ctx.writeAndFlush(response);
                                } catch (Throwable e) {
                                    log.error("process request over, but response failed", e);
                                    log.error(cmd.toString());
                                    log.error(response.toString());
                                }
                            } else {

                            }
                        }
                    } catch (Throwable e) {
                        log.error("process request exception", e);
                        log.error(cmd.toString());

                        if (!cmd.isOnewayRPC()) {
                            final RemotingCommand response = RemotingCommand.createResponseCommand(RemotingSysResponseCode.SYSTEM_ERROR,
                                RemotingHelper.exceptionSimpleDesc(e));
                            response.setOpaque(opaque);
                            ctx.writeAndFlush(response);
                        }
                    }
                }
            };

            if (pair.getObject1().rejectRequest()) {
                final RemotingCommand response = RemotingCommand.createResponseCommand(RemotingSysResponseCode.SYSTEM_BUSY,
                    "[REJECTREQUEST]system busy, start flow control for a while");
                response.setOpaque(opaque);
                ctx.writeAndFlush(response);
                return;
            }

            try {
                final RequestTask requestTask = new RequestTask(run, ctx.channel(), cmd);
                pair.getObject2().submit(requestTask);
            } catch (RejectedExecutionException e) {
                if ((System.currentTimeMillis() % 10000) == 0) {
                    log.warn(RemotingHelper.parseChannelRemoteAddr(ctx.channel())
                        + ", too many requests and system thread pool busy, RejectedExecutionException "
                        + pair.getObject2().toString()
                        + " request code: " + cmd.getCode());
                }

                if (!cmd.isOnewayRPC()) {
                    final RemotingCommand response = RemotingCommand.createResponseCommand(RemotingSysResponseCode.SYSTEM_BUSY,
                        "[OVERLOAD]system busy, start flow control for a while");
                    response.setOpaque(opaque);
                    ctx.writeAndFlush(response);
                }
            }
        } else {
            String error = " request type " + cmd.getCode() + " not supported";
            final RemotingCommand response =
                RemotingCommand.createResponseCommand(RemotingSysResponseCode.REQUEST_CODE_NOT_SUPPORTED, error);
            response.setOpaque(opaque);
            ctx.writeAndFlush(response);
            log.error(RemotingHelper.parseChannelRemoteAddr(ctx.channel()) + error);
        }
    }

• 这里根据上下文准备好runnable，然后构建RequestTask，放入到pair的executor中执行
• 这里的pair为Pair<NettyRequestProcessor, ExecutorService>，每个request code对应一个pair

NettyRemotingServer.registerProcessor

org/apache/rocketmq/remoting/netty/NettyRemotingServer.java

    public void registerProcessor(int requestCode, NettyRequestProcessor processor, ExecutorService executor) {
        ExecutorService executorThis = executor;
        if (null == executor) {
            executorThis = this.publicExecutor;
        }

        Pair<NettyRequestProcessor, ExecutorService> pair = new Pair<NettyRequestProcessor, ExecutorService>(processor, executorThis);
        this.processorTable.put(requestCode, pair);
    }

• registerProcessor方法会给requestCode添加一个Pair<NettyRequestProcessor, ExecutorService>

BrokerController.registerProcessor

org/apache/rocketmq/broker/BrokerController.java

    private ExecutorService sendMessageExecutor;
    private ExecutorService pullMessageExecutor;
    private ExecutorService queryMessageExecutor;
    private ExecutorService adminBrokerExecutor;
    private ExecutorService clientManageExecutor;
    private ExecutorService consumerManageExecutor;

    //......

    public void registerProcessor() {
        /**
         * SendMessageProcessor
         */
        SendMessageProcessor sendProcessor = new SendMessageProcessor(this);
        sendProcessor.registerSendMessageHook(sendMessageHookList);
        sendProcessor.registerConsumeMessageHook(consumeMessageHookList);

        this.remotingServer.registerProcessor(RequestCode.SEND_MESSAGE, sendProcessor, this.sendMessageExecutor);
        this.remotingServer.registerProcessor(RequestCode.SEND_MESSAGE_V2, sendProcessor, this.sendMessageExecutor);
        this.remotingServer.registerProcessor(RequestCode.SEND_BATCH_MESSAGE, sendProcessor, this.sendMessageExecutor);
        this.remotingServer.registerProcessor(RequestCode.CONSUMER_SEND_MSG_BACK, sendProcessor, this.sendMessageExecutor);
        this.fastRemotingServer.registerProcessor(RequestCode.SEND_MESSAGE, sendProcessor, this.sendMessageExecutor);
        this.fastRemotingServer.registerProcessor(RequestCode.SEND_MESSAGE_V2, sendProcessor, this.sendMessageExecutor);
        this.fastRemotingServer.registerProcessor(RequestCode.SEND_BATCH_MESSAGE, sendProcessor, this.sendMessageExecutor);
        this.fastRemotingServer.registerProcessor(RequestCode.CONSUMER_SEND_MSG_BACK, sendProcessor, this.sendMessageExecutor);
        /**
         * PullMessageProcessor
         */
        this.remotingServer.registerProcessor(RequestCode.PULL_MESSAGE, this.pullMessageProcessor, this.pullMessageExecutor);
        this.pullMessageProcessor.registerConsumeMessageHook(consumeMessageHookList);

        /**
         * QueryMessageProcessor
         */
        NettyRequestProcessor queryProcessor = new QueryMessageProcessor(this);
        this.remotingServer.registerProcessor(RequestCode.QUERY_MESSAGE, queryProcessor, this.queryMessageExecutor);
        this.remotingServer.registerProcessor(RequestCode.VIEW_MESSAGE_BY_ID, queryProcessor, this.queryMessageExecutor);

        this.fastRemotingServer.registerProcessor(RequestCode.QUERY_MESSAGE, queryProcessor, this.queryMessageExecutor);
        this.fastRemotingServer.registerProcessor(RequestCode.VIEW_MESSAGE_BY_ID, queryProcessor, this.queryMessageExecutor);

        /**
         * ClientManageProcessor
         */
        ClientManageProcessor clientProcessor = new ClientManageProcessor(this);
        this.remotingServer.registerProcessor(RequestCode.HEART_BEAT, clientProcessor, this.clientManageExecutor);
        this.remotingServer.registerProcessor(RequestCode.UNREGISTER_CLIENT, clientProcessor, this.clientManageExecutor);
        this.remotingServer.registerProcessor(RequestCode.CHECK_CLIENT_CONFIG, clientProcessor, this.clientManageExecutor);

        this.fastRemotingServer.registerProcessor(RequestCode.HEART_BEAT, clientProcessor, this.clientManageExecutor);
        this.fastRemotingServer.registerProcessor(RequestCode.UNREGISTER_CLIENT, clientProcessor, this.clientManageExecutor);
        this.fastRemotingServer.registerProcessor(RequestCode.CHECK_CLIENT_CONFIG, clientProcessor, this.clientManageExecutor);

        /**
         * ConsumerManageProcessor
         */
        ConsumerManageProcessor consumerManageProcessor = new ConsumerManageProcessor(this);
        this.remotingServer.registerProcessor(RequestCode.GET_CONSUMER_LIST_BY_GROUP, consumerManageProcessor, this.consumerManageExecutor);
        this.remotingServer.registerProcessor(RequestCode.UPDATE_CONSUMER_OFFSET, consumerManageProcessor, this.consumerManageExecutor);
        this.remotingServer.registerProcessor(RequestCode.QUERY_CONSUMER_OFFSET, consumerManageProcessor, this.consumerManageExecutor);

        this.fastRemotingServer.registerProcessor(RequestCode.GET_CONSUMER_LIST_BY_GROUP, consumerManageProcessor, this.consumerManageExecutor);
        this.fastRemotingServer.registerProcessor(RequestCode.UPDATE_CONSUMER_OFFSET, consumerManageProcessor, this.consumerManageExecutor);
        this.fastRemotingServer.registerProcessor(RequestCode.QUERY_CONSUMER_OFFSET, consumerManageProcessor, this.consumerManageExecutor);

        /**
         * EndTransactionProcessor
         */
        this.remotingServer.registerProcessor(RequestCode.END_TRANSACTION, new EndTransactionProcessor(this), this.sendMessageExecutor);
        this.fastRemotingServer.registerProcessor(RequestCode.END_TRANSACTION, new EndTransactionProcessor(this), this.sendMessageExecutor);

        /**
         * Default
         */
        AdminBrokerProcessor adminProcessor = new AdminBrokerProcessor(this);
        this.remotingServer.registerDefaultProcessor(adminProcessor, this.adminBrokerExecutor);
        this.fastRemotingServer.registerDefaultProcessor(adminProcessor, this.adminBrokerExecutor);
    }

• 这里一共分了sendMessageExecutor、pullMessageExecutor、queryMessageExecutor、adminBrokerExecutor、clientManageExecutor、consumerManageExecutor五个executor

小结

BrokerController给每个命令号注册了对应的executor，然后RequestTask在其命令号对应的executor中执行，不同的命令分开executor执行，进行了隔离，避免相互影响。

doc

• RequestTask