RocketMQ源码分析之Broker注册（2）

编程语言 2019-04-20 19:10:50 阅读次数: 0
版权声明： https://blog.csdn.net/ph3636/article/details/89421700

NameServer响应Broker请求查询注册版本，对于注册中心来说对应的是请求命令，处理方法如下，根据对应的code找出对应的处理类，这里只有一个默认处理类DefaultRequestProcessor，处理过程执行前后置钩子方法，把请求和通信通道组成一个任务提交到处理器对应的的线程池中执行，查询请求是经过编码发送到nameserver的，经过NettyClientHandler处理请求命令

class NettyClientHandler extends SimpleChannelInboundHandler<RemotingCommand> {

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
        processMessageReceived(ctx, msg);
    }
}
 public void processMessageReceived(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
    final RemotingCommand cmd = msg;
    if (cmd != null) {
        switch (cmd.getType()) {
            case REQUEST_COMMAND:
                processRequestCommand(ctx, cmd);
                break;
            case RESPONSE_COMMAND:
                processResponseCommand(ctx, cmd);
                break;
            default:
                break;
        }
    }
}

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 {
                    doBeforeRpcHooks(RemotingHelper.parseChannelRemoteAddr(ctx.channel()), cmd);
                    final RemotingCommand response = pair.getObject1().processRequest(ctx, cmd);
                    doAfterRpcHooks(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);
    }
}

对应的code与处理方法如下

@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx,
    RemotingCommand request) throws RemotingCommandException {

    if (ctx != null) {
        log.debug("receive request, {} {} {}",
            request.getCode(),
            RemotingHelper.parseChannelRemoteAddr(ctx.channel()),
            request);
    }


    switch (request.getCode()) {
        case RequestCode.PUT_KV_CONFIG:
            return this.putKVConfig(ctx, request);
        case RequestCode.GET_KV_CONFIG:
            return this.getKVConfig(ctx, request);
        case RequestCode.DELETE_KV_CONFIG:
            return this.deleteKVConfig(ctx, request);
        case RequestCode.QUERY_DATA_VERSION:
            return queryBrokerTopicConfig(ctx, request);
        case RequestCode.REGISTER_BROKER:
            Version brokerVersion = MQVersion.value2Version(request.getVersion());
            if (brokerVersion.ordinal() >= MQVersion.Version.V3_0_11.ordinal()) {
                return this.registerBrokerWithFilterServer(ctx, request);
            } else {
                return this.registerBroker(ctx, request);
            }
        case RequestCode.UNREGISTER_BROKER:
            return this.unregisterBroker(ctx, request);
        case RequestCode.GET_ROUTEINTO_BY_TOPIC:
            return this.getRouteInfoByTopic(ctx, request);
        case RequestCode.GET_BROKER_CLUSTER_INFO:
            return this.getBrokerClusterInfo(ctx, request);
        case RequestCode.WIPE_WRITE_PERM_OF_BROKER:
            return this.wipeWritePermOfBroker(ctx, request);
        case RequestCode.GET_ALL_TOPIC_LIST_FROM_NAMESERVER:
            return getAllTopicListFromNameserver(ctx, request);
        case RequestCode.DELETE_TOPIC_IN_NAMESRV:
            return deleteTopicInNamesrv(ctx, request);
        case RequestCode.GET_KVLIST_BY_NAMESPACE:
            return this.getKVListByNamespace(ctx, request);
        case RequestCode.GET_TOPICS_BY_CLUSTER:
            return this.getTopicsByCluster(ctx, request);
        case RequestCode.GET_SYSTEM_TOPIC_LIST_FROM_NS:
            return this.getSystemTopicListFromNs(ctx, request);
        case RequestCode.GET_UNIT_TOPIC_LIST:
            return this.getUnitTopicList(ctx, request);
        case RequestCode.GET_HAS_UNIT_SUB_TOPIC_LIST:
            return this.getHasUnitSubTopicList(ctx, request);
        case RequestCode.GET_HAS_UNIT_SUB_UNUNIT_TOPIC_LIST:
            return this.getHasUnitSubUnUnitTopicList(ctx, request);
        case RequestCode.UPDATE_NAMESRV_CONFIG:
            return this.updateConfig(ctx, request);
        case RequestCode.GET_NAMESRV_CONFIG:
            return this.getConfig(ctx, request);
        default:
            break;
    }
    return null;
}

创建对应的响应头QueryDataVersionResponseHeader，解析出请求实体中包含的版本数据DataVersion


public RemotingCommand queryBrokerTopicConfig(ChannelHandlerContext ctx,
    RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(QueryDataVersionResponseHeader.class);
    final QueryDataVersionResponseHeader responseHeader = (QueryDataVersionResponseHeader) response.readCustomHeader();
    final QueryDataVersionRequestHeader requestHeader =
        (QueryDataVersionRequestHeader) request.decodeCommandCustomHeader(QueryDataVersionRequestHeader.class);
    DataVersion dataVersion = DataVersion.decode(request.getBody(), DataVersion.class);

    Boolean changed = this.namesrvController.getRouteInfoManager().isBrokerTopicConfigChanged(requestHeader.getBrokerAddr(), dataVersion);
    if (!changed) {
        this.namesrvController.getRouteInfoManager().updateBrokerInfoUpdateTimestamp(requestHeader.getBrokerAddr());
    }

    DataVersion nameSeverDataVersion = this.namesrvController.getRouteInfoManager().queryBrokerTopicConfig(requestHeader.getBrokerAddr());
    response.setCode(ResponseCode.SUCCESS);
    response.setRemark(null);

    if (nameSeverDataVersion != null) {
        response.setBody(nameSeverDataVersion.encode());
    }
    responseHeader.setChanged(changed);
    return response;
}

从注册中心中的topic路由管理类中查找该broker的心跳版本信息，然后进行对比后返回是否更改过，如果没有更改过的话就更新心跳信息的最新的更新事件

public boolean isBrokerTopicConfigChanged(final String brokerAddr, final DataVersion dataVersion) {
    DataVersion prev = queryBrokerTopicConfig(brokerAddr);
    return null == prev || !prev.equals(dataVersion);
}

public DataVersion queryBrokerTopicConfig(final String brokerAddr) {
    BrokerLiveInfo prev = this.brokerLiveTable.get(brokerAddr);
    if (prev != null) {
        return prev.getDataVersion();
    }
    return null;
}

public void updateBrokerInfoUpdateTimestamp(final String brokerAddr) {
    BrokerLiveInfo prev = this.brokerLiveTable.get(brokerAddr);
    if (prev != null) {
        prev.setLastUpdateTimestamp(System.currentTimeMillis());
    }
}

最后查询最新的信息后设置返回命令的body后返回响应，响应到达broker是通过解码接收后经过NettyClientHandler处理，对应的是响应命令，根据请求id找到对应的ResponseFuture，设置对应的响应结果，如果有回调的话就会执行回调方法。

public void processResponseCommand(ChannelHandlerContext ctx, RemotingCommand cmd) {
    final int opaque = cmd.getOpaque();
    final ResponseFuture responseFuture = responseTable.get(opaque);
    if (responseFuture != null) {
        responseFuture.setResponseCommand(cmd);

        responseTable.remove(opaque);

        if (responseFuture.getInvokeCallback() != null) {
            executeInvokeCallback(responseFuture);
        } else {
            responseFuture.putResponse(cmd);
            responseFuture.release();
        }
    } else {
        log.warn("receive response, but not matched any request, " + RemotingHelper.parseChannelRemoteAddr(ctx.channel()));
        log.warn(cmd.toString());
    }
}

执行rpc后置钩子


protected void doAfterRpcHooks(String addr, RemotingCommand request, RemotingCommand response) {
    if (rpcHooks.size() > 0) {
        for (RPCHook rpcHook: rpcHooks) {
            rpcHook.doAfterResponse(addr, request, response);
        }
    }
}

最后根据返回code解析出返回数据头QueryDataVersionResponseHeader以及具体内容，对比后返回该次请求需要的结果。

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