rocketmq源碼解析之管理請求獲取消費者狀態

說在前面

管理請求 INVOKE_BROKER_TO_GET_CONSUMER_STATUS 獲取消費者狀態

 

源碼解析

進入這個方法org.apache.rocketmq.broker.processor.AdminBrokerProcessor#getConsumerStatus獲取消費者狀態

public RemotingCommand getConsumerStatus(ChannelHandlerContext ctx,
        RemotingCommand request) throws RemotingCommandException {
        final GetConsumerStatusRequestHeader requestHeader =
            (GetConsumerStatusRequestHeader) request.decodeCommandCustomHeader(GetConsumerStatusRequestHeader.class);
        log.info("[get-consumer-status] get consumer status by {}. topic={}, group={}",
            RemotingHelper.parseChannelRemoteAddr(ctx.channel()), requestHeader.getTopic(), requestHeader.getGroup());
//        =》
        return this.brokerController.getBroker2Client().getConsumeStatus(requestHeader.getTopic(), requestHeader.getGroup(),
            requestHeader.getClientAddr());
    }

進入這個方法org.apache.rocketmq.broker.client.net.Broker2Client#getConsumeStatus

public RemotingCommand getConsumeStatus(String topic, String group, String originClientId) {
        final RemotingCommand result = RemotingCommand.createResponseCommand(null);
        GetConsumerStatusRequestHeader requestHeader = new GetConsumerStatusRequestHeader();
        requestHeader.setTopic(topic);
        requestHeader.setGroup(group);
        RemotingCommand request =
            RemotingCommand.createRequestCommand(RequestCode.GET_CONSUMER_STATUS_FROM_CLIENT,
                requestHeader);
        Map<String, Map<MessageQueue, Long>> consumerStatusTable =
            new HashMap<String, Map<MessageQueue, Long>>();
//        獲取消費組的渠道緩存信息
        ConcurrentMap<Channel, ClientChannelInfo> channelInfoTable =
            this.brokerController.getConsumerManager().getConsumerGroupInfo(group).getChannelInfoTable();
        if (null == channelInfoTable || channelInfoTable.isEmpty()) {
            result.setCode(ResponseCode.SYSTEM_ERROR);
            result.setRemark(String.format("No Any Consumer online in the consumer group: [%s]", group));
            return result;
        }

        for (Map.Entry<Channel, ClientChannelInfo> entry : channelInfoTable.entrySet()) {
            int version = entry.getValue().getVersion();
            String clientId = entry.getValue().getClientId();
            if (version < MQVersion.Version.V3_0_7_SNAPSHOT.ordinal()) {
                result.setCode(ResponseCode.SYSTEM_ERROR);
                result.setRemark("the client does not support this feature. version="
                    + MQVersion.getVersionDesc(version));
                log.warn("[get-consumer-status] the client does not support this feature. version={}",
                    RemotingHelper.parseChannelRemoteAddr(entry.getKey()), MQVersion.getVersionDesc(version));
                return result;
            } else if (UtilAll.isBlank(originClientId) || originClientId.equals(clientId)) {
                try {
//                    countDownLatch實現的同步執行 =》
                    RemotingCommand response =
                        this.brokerController.getRemotingServer().invokeSync(entry.getKey(), request, 5000);
                    assert response != null;
                    switch (response.getCode()) {
                        case ResponseCode.SUCCESS: {
                            if (response.getBody() != null) {
                                GetConsumerStatusBody body =
                                    GetConsumerStatusBody.decode(response.getBody(),
                                        GetConsumerStatusBody.class);
                                consumerStatusTable.put(clientId, body.getMessageQueueTable());
                                log.info(
                                    "[get-consumer-status] get consumer status success. topic={}, group={}, channelRemoteAddr={}",
                                    topic, group, clientId);
                            }
                        }
                        default:
                            break;
                    }
                } catch (Exception e) {
                    log.error(
                        "[get-consumer-status] get consumer status exception. topic={}, group={}, offset={}",
                        new Object[] {topic, group}, e);
                }

                if (!UtilAll.isBlank(originClientId) && originClientId.equals(clientId)) {
                    break;
                }
            }
        }

        result.setCode(ResponseCode.SUCCESS);
        GetConsumerStatusBody resBody = new GetConsumerStatusBody();
        resBody.setConsumerTable(consumerStatusTable);
        result.setBody(resBody.encode());
        return result;
    }
}

進入這個方法org.apache.rocketmq.remoting.netty.NettyRemotingAbstract#invokeSyncImpl同步執行rpc請求

public RemotingCommand invokeSyncImpl(final Channel channel, final RemotingCommand request,
        final long timeoutMillis)
        throws InterruptedException, RemotingSendRequestException, RemotingTimeoutException {
        final int opaque = request.getOpaque();
        try {
            final ResponseFuture responseFuture = new ResponseFuture(channel, opaque, timeoutMillis, null, null);
//            緩存正在進行的響應
            this.responseTable.put(opaque, responseFuture);
            final SocketAddress addr = channel.remoteAddress();
            channel.writeAndFlush(request).addListener(new ChannelFutureListener() {
                @Override
                public void operationComplete(ChannelFuture f) throws Exception {
                    if (f.isSuccess()) {
                        responseFuture.setSendRequestOK(true);
                        return;
                    } else {
                        responseFuture.setSendRequestOK(false);
                    }

                    responseTable.remove(opaque);
                    responseFuture.setCause(f.cause());
//                    響應解析完畢會解除countDownLatch的阻塞 =》
                    responseFuture.putResponse(null);
                    log.warn("send a request command to channel <" + addr + "> failed.");
                }
            });
//            這裏用countDownLatch實現的阻塞 =》
            RemotingCommand responseCommand = responseFuture.waitResponse(timeoutMillis);
            if (null == responseCommand) {
                if (responseFuture.isSendRequestOK()) {
                    throw new RemotingTimeoutException(RemotingHelper.parseSocketAddressAddr(addr), timeoutMillis,
                        responseFuture.getCause());
                } else {
                    throw new RemotingSendRequestException(RemotingHelper.parseSocketAddressAddr(addr), responseFuture.getCause());
                }
            }

            return responseCommand;
        } finally {
            this.responseTable.remove(opaque);
        }
    }

這裏是countDownLatch實現的同步

 

往上返回到這個方法org.apache.rocketmq.broker.processor.AdminBrokerProcessor#getConsumerStatus結束

 

說在最後

本次解析僅表明我的觀點，僅供參考。

 

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