Prospect Review
[mq] Implement mq-01-producer and consumer startup from scratch
[mq] To implement mq-02 from scratch - how to implement a producer calling a consumer?
[mq] Implementing mq-03-introduction of broker middlemen from scratch
In the previous section, we learned how to implement producers to send messages to consumers, but through direct connections.
So how can we achieve the effect of decoupling?
The answer is to introduce brokers, the middlemen of messages.
MqBroker implementation
core startup class
Similar to the startup implementation of our previous consumer:
package com.github.houbb.mq.broker.core;
/**
* @author binbin.hou
* @since 1.0.0
*/
public class MqBroker extends Thread implements IMqBroker {
// 省略
private ChannelHandler initChannelHandler() {
MqBrokerHandler handler = new MqBrokerHandler();
handler.setInvokeService(invokeService);
handler.setRegisterConsumerService(registerConsumerService);
handler.setRegisterProducerService(registerProducerService);
handler.setMqBrokerPersist(mqBrokerPersist);
handler.setBrokerPushService(brokerPushService);
handler.setRespTimeoutMills(respTimeoutMills);
return handler;
}
@Override
public void run() {
// 启动服务端
log.info("MQ 中间人开始启动服务端 port: {}", port);
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
final ByteBuf delimiterBuf = DelimiterUtil.getByteBuf(DelimiterUtil.DELIMITER);
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(workerGroup, bossGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline()
.addLast(new DelimiterBasedFrameDecoder(DelimiterUtil.LENGTH, delimiterBuf))
.addLast(initChannelHandler());
}
})
// 这个参数影响的是还没有被accept 取出的连接
.option(ChannelOption.SO_BACKLOG, 128)
// 这个参数只是过一段时间内客户端没有响应，服务端会发送一个 ack 包，以判断客户端是否还活着。
.childOption(ChannelOption.SO_KEEPALIVE, true);
// 绑定端口，开始接收进来的链接
ChannelFuture channelFuture = serverBootstrap.bind(port).syncUninterruptibly();
log.info("MQ 中间人启动完成，监听【" + port + "】端口");
channelFuture.channel().closeFuture().syncUninterruptibly();
log.info("MQ 中间人关闭完成");
} catch (Exception e) {
log.error("MQ 中间人启动异常", e);
throw new MqException(BrokerRespCode.RPC_INIT_FAILED);
} finally {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
}
} initChannelHandler There are quite a few new faces, which we will introduce in detail later.
MqBrokerHandler processing logic
package com.github.houbb.mq.broker.handler;
import java.util.List;
/**
* @author binbin.hou
* @since 1.0.0
*/
public class MqBrokerHandler extends SimpleChannelInboundHandler {
private static final Log log = LogFactory.getLog(MqBrokerHandler.class);
/**
* 调用管理类
* @since 1.0.0
*/
private IInvokeService invokeService;
/**
* 消费者管理
* @since 0.0.3
*/
private IBrokerConsumerService registerConsumerService;
/**
* 生产者管理
* @since 0.0.3
*/
private IBrokerProducerService registerProducerService;
/**
* 持久化类
* @since 0.0.3
*/
private IMqBrokerPersist mqBrokerPersist;
/**
* 推送服务
* @since 0.0.3
*/
private IBrokerPushService brokerPushService;
/**
* 获取响应超时时间
* @since 0.0.3
*/
private long respTimeoutMills;
//set 方法
@Override
protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
ByteBuf byteBuf = (ByteBuf) msg;
byte[] bytes = new byte[byteBuf.readableBytes()];
byteBuf.readBytes(bytes);
RpcMessageDto rpcMessageDto = null;
try {
rpcMessageDto = JSON.parseObject(bytes, RpcMessageDto.class);
} catch (Exception exception) {
log.error("RpcMessageDto json 格式转换异常 {}", new String(bytes));
return;
}
if (rpcMessageDto.isRequest()) {
MqCommonResp commonResp = this.dispatch(rpcMessageDto, ctx);
if(commonResp == null) {
log.debug("当前消息为 null，忽略处理。");
return;
}
// 写回响应，和以前类似。
writeResponse(rpcMessageDto, commonResp, ctx);
} else {
final String traceId = rpcMessageDto.getTraceId();
// 丢弃掉 traceId 为空的信息
if(StringUtil.isBlank(traceId)) {
log.debug("[Server Response] response traceId 为空，直接丢弃", JSON.toJSON(rpcMessageDto));
return;
}
// 添加消息
invokeService.addResponse(traceId, rpcMessageDto);
}
}
/**
* 异步处理消息
* @param mqMessage 消息
* @since 0.0.3
*/
private void asyncHandleMessage(MqMessage mqMessage) {
List<Channel> channelList = registerConsumerService.getSubscribeList(mqMessage);
if(CollectionUtil.isEmpty(channelList)) {
log.info("监听列表为空，忽略处理");
return;
}
BrokerPushContext brokerPushContext = new BrokerPushContext();
brokerPushContext.setChannelList(channelList);
brokerPushContext.setMqMessage(mqMessage);
brokerPushContext.setMqBrokerPersist(mqBrokerPersist);
brokerPushContext.setInvokeService(invokeService);
brokerPushContext.setRespTimeoutMills(respTimeoutMills);
brokerPushService.asyncPush(brokerPushContext);
}
}message distribution
After the broker receives the message, the dispatch is implemented as follows:
/**
* 消息的分发
*
* @param rpcMessageDto 入参
* @param ctx 上下文
* @return 结果
*/
private MqCommonResp dispatch(RpcMessageDto rpcMessageDto, ChannelHandlerContext ctx) {
try {
final String methodType = rpcMessageDto.getMethodType();
final String json = rpcMessageDto.getJson();
String channelId = ChannelUtil.getChannelId(ctx);
final Channel channel = ctx.channel();
log.debug("channelId: {} 接收到 method: {} 内容：{}", channelId,
methodType, json);
// 生产者注册
if(MethodType.P_REGISTER.equals(methodType)) {
BrokerRegisterReq registerReq = JSON.parseObject(json, BrokerRegisterReq.class);
return registerProducerService.register(registerReq.getServiceEntry(), channel);
}
// 生产者注销
if(MethodType.P_UN_REGISTER.equals(methodType)) {
BrokerRegisterReq registerReq = JSON.parseObject(json, BrokerRegisterReq.class);
return registerProducerService.unRegister(registerReq.getServiceEntry(), channel);
}
// 生产者消息发送
if(MethodType.P_SEND_MSG.equals(methodType)) {
MqMessage mqMessage = JSON.parseObject(json, MqMessage.class);
MqMessagePersistPut persistPut = new MqMessagePersistPut();
persistPut.setMqMessage(mqMessage);
persistPut.setMessageStatus(MessageStatusConst.WAIT_CONSUMER);
MqCommonResp commonResp = mqBrokerPersist.put(persistPut);
this.asyncHandleMessage(mqMessage);
return commonResp;
}
// 生产者消息发送-ONE WAY
if(MethodType.P_SEND_MSG_ONE_WAY.equals(methodType)) {
MqMessage mqMessage = JSON.parseObject(json, MqMessage.class);
MqMessagePersistPut persistPut = new MqMessagePersistPut();
persistPut.setMqMessage(mqMessage);
persistPut.setMessageStatus(MessageStatusConst.WAIT_CONSUMER);
mqBrokerPersist.put(persistPut);
this.asyncHandleMessage(mqMessage);
return null;
}
// 消费者注册
if(MethodType.C_REGISTER.equals(methodType)) {
BrokerRegisterReq registerReq = JSON.parseObject(json, BrokerRegisterReq.class);
return registerConsumerService.register(registerReq.getServiceEntry(), channel);
}
// 消费者注销
if(MethodType.C_UN_REGISTER.equals(methodType)) {
BrokerRegisterReq registerReq = JSON.parseObject(json, BrokerRegisterReq.class);
return registerConsumerService.unRegister(registerReq.getServiceEntry(), channel);
}
// 消费者监听注册
if(MethodType.C_SUBSCRIBE.equals(methodType)) {
ConsumerSubscribeReq req = JSON.parseObject(json, ConsumerSubscribeReq.class);
return registerConsumerService.subscribe(req, channel);
}
// 消费者监听注销
if(MethodType.C_UN_SUBSCRIBE.equals(methodType)) {
ConsumerUnSubscribeReq req = JSON.parseObject(json, ConsumerUnSubscribeReq.class);
return registerConsumerService.unSubscribe(req, channel);
}
// 消费者主动 pull
if(MethodType.C_MESSAGE_PULL.equals(methodType)) {
MqConsumerPullReq req = JSON.parseObject(json, MqConsumerPullReq.class);
return mqBrokerPersist.pull(req, channel);
}
throw new UnsupportedOperationException("暂不支持的方法类型");
} catch (Exception exception) {
log.error("执行异常", exception);
MqCommonResp resp = new MqCommonResp();
resp.setRespCode(MqCommonRespCode.FAIL.getCode());
resp.setRespMessage(MqCommonRespCode.FAIL.getMsg());
return resp;
}
}message push
this.asyncHandleMessage(mqMessage); is the processing logic after the broker receives the message.
/**
* 异步处理消息
* @param mqMessage 消息
* @since 0.0.3
*/
private void asyncHandleMessage(MqMessage mqMessage) {
List<Channel> channelList = registerConsumerService.getSubscribeList(mqMessage);
if(CollectionUtil.isEmpty(channelList)) {
log.info("监听列表为空，忽略处理");
return;
}
BrokerPushContext brokerPushContext = new BrokerPushContext();
brokerPushContext.setChannelList(channelList);
brokerPushContext.setMqMessage(mqMessage);
brokerPushContext.setMqBrokerPersist(mqBrokerPersist);
brokerPushContext.setInvokeService(invokeService);
brokerPushContext.setRespTimeoutMills(respTimeoutMills);
brokerPushService.asyncPush(brokerPushContext);
}The core implementation of push is as follows:
package com.github.houbb.mq.broker.support.push;
/**
* @author binbin.hou
* @since 0.0.3
*/
public class BrokerPushService implements IBrokerPushService {
private static final Log log = LogFactory.getLog(BrokerPushService.class);
private static final ExecutorService EXECUTOR_SERVICE = Executors.newSingleThreadExecutor();
@Override
public void asyncPush(final BrokerPushContext context) {
EXECUTOR_SERVICE.submit(new Runnable() {
@Override
public void run() {
log.info("开始异步处理 {}", JSON.toJSON(context));
final List<Channel> channelList = context.getChannelList();
final IMqBrokerPersist mqBrokerPersist = context.getMqBrokerPersist();
final MqMessage mqMessage = context.getMqMessage();
final String messageId = mqMessage.getTraceId();
final IInvokeService invokeService = context.getInvokeService();
final long responseTime = context.getRespTimeoutMills();
for(Channel channel : channelList) {
try {
String channelId = ChannelUtil.getChannelId(channel);
log.info("开始处理 channelId: {}", channelId);
//1. 调用
mqMessage.setMethodType(MethodType.B_MESSAGE_PUSH);
MqConsumerResultResp resultResp = callServer(channel, mqMessage,
MqConsumerResultResp.class, invokeService, responseTime);
//2. 更新状态
mqBrokerPersist.updateStatus(messageId, resultResp.getConsumerStatus());
//3. 后期添加重试策略
log.info("完成处理 channelId: {}", channelId);
} catch (Exception exception) {
log.error("处理异常");
mqBrokerPersist.updateStatus(messageId, ConsumerStatus.FAILED.getCode());
}
}
log.info("完成异步处理");
}
});
}
}Here, after the message is pushed, the ACK status of the message needs to be updated.
Message producer processing class
IBrokerProducerService interface is defined as follows:
package com.github.houbb.mq.broker.api;
/**
* <p> 生产者注册服务类 </p>
*
* @author houbinbin
* @since 0.0.3
*/
public interface IBrokerProducerService {
/**
* 注册当前服务信息
* （1）将该服务通过 {@link ServiceEntry#getGroupName()} 进行分组
* 订阅了这个 serviceId 的所有客户端
* @param serviceEntry 注册当前服务信息
* @param channel channel
* @since 0.0.8
*/
MqCommonResp register(final ServiceEntry serviceEntry, Channel channel);
/**
* 注销当前服务信息
* @param serviceEntry 注册当前服务信息
* @param channel 通道
* @since 0.0.8
*/
MqCommonResp unRegister(final ServiceEntry serviceEntry, Channel channel);
/**
* 获取服务地址信息
* @param channel channel
* @return 结果
* @since 0.0.3
*/
ServiceEntry getServiceEntry(final Channel channel);
}The implementation is as follows:
The basic information requested is stored locally based on the map.
package com.github.houbb.mq.broker.support.api;
/**
* <p> 生产者注册服务类 </p>
*
* @author houbinbin
* @since 0.0.3
*/
public class LocalBrokerProducerService implements IBrokerProducerService {
private static final Log log = LogFactory.getLog(LocalBrokerProducerService.class);
private final Map<String, BrokerServiceEntryChannel> registerMap = new ConcurrentHashMap<>();
@Override
public MqCommonResp register(ServiceEntry serviceEntry, Channel channel) {
final String channelId = ChannelUtil.getChannelId(channel);
BrokerServiceEntryChannel entryChannel = InnerChannelUtils.buildEntryChannel(serviceEntry, channel);
registerMap.put(channelId, entryChannel);
MqCommonResp resp = new MqCommonResp();
resp.setRespCode(MqCommonRespCode.SUCCESS.getCode());
resp.setRespMessage(MqCommonRespCode.SUCCESS.getMsg());
return resp;
}
@Override
public MqCommonResp unRegister(ServiceEntry serviceEntry, Channel channel) {
final String channelId = ChannelUtil.getChannelId(channel);
registerMap.remove(channelId);
MqCommonResp resp = new MqCommonResp();
resp.setRespCode(MqCommonRespCode.SUCCESS.getCode());
resp.setRespMessage(MqCommonRespCode.SUCCESS.getMsg());
return resp;
}
@Override
public ServiceEntry getServiceEntry(Channel channel) {
final String channelId = ChannelUtil.getChannelId(channel);
return registerMap.get(channelId);
}
}Message consumer processing class
The interface is defined as follows:
package com.github.houbb.mq.broker.api;
/**
* <p> 消费者注册服务类 </p>
*
* @author houbinbin
* @since 0.0.3
*/
public interface IBrokerConsumerService {
/**
* 注册当前服务信息
* （1）将该服务通过 {@link ServiceEntry#getGroupName()} 进行分组
* 订阅了这个 serviceId 的所有客户端
* @param serviceEntry 注册当前服务信息
* @param channel channel
* @since 0.0.3
*/
MqCommonResp register(final ServiceEntry serviceEntry, Channel channel);
/**
* 注销当前服务信息
* @param serviceEntry 注册当前服务信息
* @param channel channel
* @since 0.0.3
*/
MqCommonResp unRegister(final ServiceEntry serviceEntry, Channel channel);
/**
* 监听服务信息
* （1）监听之后，如果有任何相关的机器信息发生变化，则进行推送。
* （2）内置的信息，需要传送 ip 信息到注册中心。
*
* @param serviceEntry 客户端明细信息
* @param clientChannel 客户端 channel 信息
* @since 0.0.3
*/
MqCommonResp subscribe(final ConsumerSubscribeReq serviceEntry,
final Channel clientChannel);
/**
* 取消监听服务信息
* （1）监听之后，如果有任何相关的机器信息发生变化，则进行推送。
* （2）内置的信息，需要传送 ip 信息到注册中心。
*
* @param serviceEntry 客户端明细信息
* @param clientChannel 客户端 channel 信息
* @since 0.0.3
*/
MqCommonResp unSubscribe(final ConsumerUnSubscribeReq serviceEntry,
final Channel clientChannel);
/**
* 获取所有匹配的消费者
* 1. 同一个 groupName 只返回一个，注意负载均衡
* 2. 返回匹配当前消息的消费者通道
*
* @param mqMessage 消息体
* @return 结果
*/
List<Channel> getSubscribeList(MqMessage mqMessage);
}Default implementation:
package com.github.houbb.mq.broker.support.api;
/**
* @author binbin.hou
* @since 1.0.0
*/
public class LocalBrokerConsumerService implements IBrokerConsumerService {
private final Map<String, BrokerServiceEntryChannel> registerMap = new ConcurrentHashMap<>();
/**
* 订阅集合
* key: topicName
* value: 对应的订阅列表
*/
private final Map<String, Set<ConsumerSubscribeBo>> subscribeMap = new ConcurrentHashMap<>();
@Override
public MqCommonResp register(ServiceEntry serviceEntry, Channel channel) {
final String channelId = ChannelUtil.getChannelId(channel);
BrokerServiceEntryChannel entryChannel = InnerChannelUtils.buildEntryChannel(serviceEntry, channel);
registerMap.put(channelId, entryChannel);
MqCommonResp resp = new MqCommonResp();
resp.setRespCode(MqCommonRespCode.SUCCESS.getCode());
resp.setRespMessage(MqCommonRespCode.SUCCESS.getMsg());
return resp;
}
@Override
public MqCommonResp unRegister(ServiceEntry serviceEntry, Channel channel) {
final String channelId = ChannelUtil.getChannelId(channel);
registerMap.remove(channelId);
MqCommonResp resp = new MqCommonResp();
resp.setRespCode(MqCommonRespCode.SUCCESS.getCode());
resp.setRespMessage(MqCommonRespCode.SUCCESS.getMsg());
return resp;
}
@Override
public MqCommonResp subscribe(ConsumerSubscribeReq serviceEntry, Channel clientChannel) {
final String channelId = ChannelUtil.getChannelId(clientChannel);
final String topicName = serviceEntry.getTopicName();
Set<ConsumerSubscribeBo> set = subscribeMap.get(topicName);
if(set == null) {
set = new HashSet<>();
}
ConsumerSubscribeBo subscribeBo = new ConsumerSubscribeBo();
subscribeBo.setChannelId(channelId);
subscribeBo.setGroupName(serviceEntry.getGroupName());
subscribeBo.setTopicName(topicName);
subscribeBo.setTagRegex(serviceEntry.getTagRegex());
set.add(subscribeBo);
subscribeMap.put(topicName, set);
MqCommonResp resp = new MqCommonResp();
resp.setRespCode(MqCommonRespCode.SUCCESS.getCode());
resp.setRespMessage(MqCommonRespCode.SUCCESS.getMsg());
return resp;
}
@Override
public MqCommonResp unSubscribe(ConsumerUnSubscribeReq serviceEntry, Channel clientChannel) {
final String channelId = ChannelUtil.getChannelId(clientChannel);
final String topicName = serviceEntry.getTopicName();
ConsumerSubscribeBo subscribeBo = new ConsumerSubscribeBo();
subscribeBo.setChannelId(channelId);
subscribeBo.setGroupName(serviceEntry.getGroupName());
subscribeBo.setTopicName(topicName);
subscribeBo.setTagRegex(serviceEntry.getTagRegex());
// 集合
Set<ConsumerSubscribeBo> set = subscribeMap.get(topicName);
if(CollectionUtil.isNotEmpty(set)) {
set.remove(subscribeBo);
}
MqCommonResp resp = new MqCommonResp();
resp.setRespCode(MqCommonRespCode.SUCCESS.getCode());
resp.setRespMessage(MqCommonRespCode.SUCCESS.getMsg());
return resp;
}
@Override
public List<Channel> getSubscribeList(MqMessage mqMessage) {
final String topicName = mqMessage.getTopic();
Set<ConsumerSubscribeBo> set = subscribeMap.get(topicName);
if(CollectionUtil.isEmpty(set)) {
return Collections.emptyList();
}
//2. 获取匹配的 tag 列表
final List<String> tagNameList = mqMessage.getTags();
Map<String, List<ConsumerSubscribeBo>> groupMap = new HashMap<>();
for(ConsumerSubscribeBo bo : set) {
String tagRegex = bo.getTagRegex();
if(hasMatch(tagNameList, tagRegex)) {
//TODO: 这种设置模式，统一添加处理
String groupName = bo.getGroupName();
List<ConsumerSubscribeBo> list = groupMap.get(groupName);
if(list == null) {
list = new ArrayList<>();
}
list.add(bo);
groupMap.put(groupName, list);
}
}
//3. 按照 groupName 分组之后，每一组只随机返回一个。最好应该调整为以 shardingkey 选择
final String shardingKey = mqMessage.getShardingKey();
List<Channel> channelList = new ArrayList<>();
for(Map.Entry<String, List<ConsumerSubscribeBo>> entry : groupMap.entrySet()) {
List<ConsumerSubscribeBo> list = entry.getValue();
ConsumerSubscribeBo bo = RandomUtils.random(list, shardingKey);
BrokerServiceEntryChannel entryChannel = registerMap.get(bo.getChannelId());
channelList.add(entryChannel.getChannel());
}
return channelList;
}
private boolean hasMatch(List<String> tagNameList,
String tagRegex) {
if(CollectionUtil.isEmpty(tagNameList)) {
return false;
}
Pattern pattern = Pattern.compile(tagRegex);
for(String tagName : tagNameList) {
if(RegexUtils.match(pattern, tagName)) {
return true;
}
}
return false;
}
} The logic of getSubscribeList may be a little more complicated. In fact, it is just a message coming and finding a matching subscriber.
Because consumer messages of the same groupName are only consumed once, a grouping is required.
message persistence
The interface is as follows:
package com.github.houbb.mq.broker.support.persist;
/**
* @author binbin.hou
* @since 0.0.3
*/
public interface IMqBrokerPersist {
/**
* 保存消息
* @param mqMessage 消息
* @since 0.0.3
*/
MqCommonResp put(final MqMessagePersistPut mqMessage);
/**
* 更新状态
* @param messageId 消息唯一标识
* @param status 状态
* @return 结果
* @since 0.0.3
*/
MqCommonResp updateStatus(final String messageId,
final String status);
/**
* 拉取消息
* @param pull 拉取消息
* @return 结果
*/
MqConsumerPullResp pull(final MqConsumerPullReq pull, final Channel channel);
}Local default implementation:
package com.github.houbb.mq.broker.support.persist;
/**
* 本地持久化策略
* @author binbin.hou
* @since 1.0.0
*/
public class LocalMqBrokerPersist implements IMqBrokerPersist {
private static final Log log = LogFactory.getLog(LocalMqBrokerPersist.class);
/**
* 队列
* ps: 这里只是简化实现，暂时不考虑并发等问题。
*/
private final Map<String, List<MqMessagePersistPut>> map = new ConcurrentHashMap<>();
//1. 接收
//2. 持久化
//3. 通知消费
@Override
public synchronized MqCommonResp put(MqMessagePersistPut put) {
log.info("put elem: {}", JSON.toJSON(put));
MqMessage mqMessage = put.getMqMessage();
final String topic = mqMessage.getTopic();
List<MqMessagePersistPut> list = map.get(topic);
if(list == null) {
list = new ArrayList<>();
}
list.add(put);
map.put(topic, list);
MqCommonResp commonResp = new MqCommonResp();
commonResp.setRespCode(MqCommonRespCode.SUCCESS.getCode());
commonResp.setRespMessage(MqCommonRespCode.SUCCESS.getMsg());
return commonResp;
}
@Override
public MqCommonResp updateStatus(String messageId, String status) {
// 这里性能比较差，所以不可以用于生产。仅作为测试验证
for(List<MqMessagePersistPut> list : map.values()) {
for(MqMessagePersistPut put : list) {
MqMessage mqMessage = put.getMqMessage();
if(mqMessage.getTraceId().equals(messageId)) {
put.setMessageStatus(status);
break;
}
}
}
MqCommonResp commonResp = new MqCommonResp();
commonResp.setRespCode(MqCommonRespCode.SUCCESS.getCode());
commonResp.setRespMessage(MqCommonRespCode.SUCCESS.getMsg());
return commonResp;
}
@Override
public MqConsumerPullResp pull(MqConsumerPullReq pull, Channel channel) {
//TODO... 待实现
return null;
}
}ps: In the future, persistence strategy will be implemented based on springboot+mysql.
Consumer Initiated Adjustment
We adjust the start of producers and consumers and connect them to the broker.
The two are similar, and here we take consumers as an example.
core startup class
package com.github.houbb.mq.consumer.core;
/**
* 推送消费策略
*
* @author binbin.hou
* @since 1.0.0
*/
public class MqConsumerPush extends Thread implements IMqConsumer {
// 属性&设置
@Override
public void run() {
// 启动服务端
log.info("MQ 消费者开始启动服务端 groupName: {}, brokerAddress: {}",
groupName, brokerAddress);
//1. 参数校验
this.paramCheck();
try {
// channel handler
ChannelHandler channelHandler = this.initChannelHandler();
//channel future
this.channelFutureList = ChannelFutureUtils.initChannelFutureList(brokerAddress, channelHandler);
// register to broker
this.registerToBroker();
// 标识为可用
enableFlag = true;
log.info("MQ 消费者启动完成");
} catch (Exception e) {
log.error("MQ 消费者启动异常", e);
throw new MqException(ConsumerRespCode.RPC_INIT_FAILED);
}
}
//订阅&取消订阅
@Override
public void registerListener(IMqConsumerListener listener) {
this.mqListenerService.register(listener);
}
}initialize handler
private ChannelHandler initChannelHandler() {
final ByteBuf delimiterBuf = DelimiterUtil.getByteBuf(DelimiterUtil.DELIMITER);
final MqConsumerHandler mqConsumerHandler = new MqConsumerHandler(invokeService, mqListenerService);
// handler 实际上会被多次调用，如果不是 @Shareable，应该每次都重新创建。
ChannelHandler handler = new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline()
.addLast(new DelimiterBasedFrameDecoder(DelimiterUtil.LENGTH, delimiterBuf))
.addLast(mqConsumerHandler);
}
};
return handler;
}Register to the server
/**
* 注册到所有的服务端
* @since 0.0.3
*/
private void registerToBroker() {
for(RpcChannelFuture channelFuture : this.channelFutureList) {
ServiceEntry serviceEntry = new ServiceEntry();
serviceEntry.setGroupName(groupName);
serviceEntry.setAddress(channelFuture.getAddress());
serviceEntry.setPort(channelFuture.getPort());
serviceEntry.setWeight(channelFuture.getWeight());
BrokerRegisterReq brokerRegisterReq = new BrokerRegisterReq();
brokerRegisterReq.setServiceEntry(serviceEntry);
brokerRegisterReq.setMethodType(MethodType.C_REGISTER);
brokerRegisterReq.setTraceId(IdHelper.uuid32());
log.info("[Register] 开始注册到 broker：{}", JSON.toJSON(brokerRegisterReq));
final Channel channel = channelFuture.getChannelFuture().channel();
MqCommonResp resp = callServer(channel, brokerRegisterReq, MqCommonResp.class);
log.info("[Register] 完成注册到 broker：{}", JSON.toJSON(resp));
}
}SUBSCRIBE AND UNSUBSCRIBE
Consumers are also relatively simple to implement for the messages they care about:
public void subscribe(String topicName, String tagRegex) {
ConsumerSubscribeReq req = new ConsumerSubscribeReq();
String messageId = IdHelper.uuid32();
req.setTraceId(messageId);
req.setMethodType(MethodType.C_SUBSCRIBE);
req.setTopicName(topicName);
req.setTagRegex(tagRegex);
req.setGroupName(groupName);
Channel channel = getChannel();
MqCommonResp resp = callServer(channel, req, MqCommonResp.class);
if(!MqCommonRespCode.SUCCESS.getCode().equals(resp.getRespCode())) {
throw new MqException(ConsumerRespCode.SUBSCRIBE_FAILED);
}
}unsubscribe:
public void unSubscribe(String topicName, String tagRegex) {
ConsumerUnSubscribeReq req = new ConsumerUnSubscribeReq();
String messageId = IdHelper.uuid32();
req.setTraceId(messageId);
req.setMethodType(MethodType.C_UN_SUBSCRIBE);
req.setTopicName(topicName);
req.setTagRegex(tagRegex);
req.setGroupName(groupName);
Channel channel = getChannel();
MqCommonResp resp = callServer(channel, req, MqCommonResp.class);
if(!MqCommonRespCode.SUCCESS.getCode().equals(resp.getRespCode())) {
throw new MqException(ConsumerRespCode.UN_SUBSCRIBE_FAILED);
}
}test
broker start
MqBroker broker = new MqBroker();
broker.start();Startup log:
[DEBUG] [2022-04-21 20:36:27.158] [main] [c.g.h.l.i.c.LogFactory.setImplementation] - Logging initialized using 'class com.github.houbb.log.integration.adaptors.stdout.StdOutExImpl' adapter.
[INFO] [2022-04-21 20:36:27.186] [Thread-0] [c.g.h.m.b.c.MqBroker.run] - MQ 中间人开始启动服务端 port: 9999
[INFO] [2022-04-21 20:36:29.060] [Thread-0] [c.g.h.m.b.c.MqBroker.run] - MQ 中间人启动完成，监听【9999】端口consumer start
final MqConsumerPush mqConsumerPush = new MqConsumerPush();
mqConsumerPush.start();
mqConsumerPush.subscribe("TOPIC", "TAGA");
mqConsumerPush.registerListener(new IMqConsumerListener() {
@Override
public ConsumerStatus consumer(MqMessage mqMessage, IMqConsumerListenerContext context) {
System.out.println("---------- 自定义 " + JSON.toJSONString(mqMessage));
return ConsumerStatus.SUCCESS;
}
});Startup log:
...
[INFO] [2022-04-21 20:37:40.985] [Thread-0] [c.g.h.m.c.c.MqConsumerPush.registerToBroker] - [Register] 完成注册到 broker：{"respMessage":"成功","respCode":"0000"}It will be registered to the broker at startup.
producer start
MqProducer mqProducer = new MqProducer();
mqProducer.start();
String message = "HELLO MQ!";
MqMessage mqMessage = new MqMessage();
mqMessage.setTopic("TOPIC");
mqMessage.setTags(Arrays.asList("TAGA", "TAGB"));
mqMessage.setPayload(message);
SendResult sendResult = mqProducer.send(mqMessage);
System.out.println(JSON.toJSON(sendResult));log:
...
[INFO] [2022-04-21 20:39:17.885] [Thread-0] [c.g.h.m.p.c.MqProducer.registerToBroker] - [Register] 完成注册到 broker：{"respMessage":"成功","respCode":"0000"}
...At this point, the consumer consumes the message we sent.
---------- 自定义 {"methodType":"B_MESSAGE_PUSH","payload":"HELLO MQ!","tags":["TAGA","TAGB"],"topic":"TOPIC","traceId":"2237bbfe55b842328134e6a100e36364"}summary
At this point, we have implemented middleman-based producer-consumer communication.
I hope this article is helpful to you. If you like it, please like, collect and forward it.
I'm an old horse, and I look forward to seeing you again next time.
open source address
The message queue in java.(java simple version mq implementation) https://github.com/houbb/mq
Extended reading
rpc - Implementing rpc from scratch https://github.com/houbb/rpc
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