Redis - 订阅发布替换 Etcd 解决方案

为了减轻项目的中间件臃肿，由于我们项目本身就应用了 Redis，正好 Redis 的也具备订阅发布监听的特性，正好应对 Etcd 的功能，所以本次给大家讲解如何使用 Redis 消息订阅发布来替代 Etcd 的解决方案。接下来，我们先看 Redis 订阅发布的常见情景……

Redis 订阅发布公共类

RedisConfig.java

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import java.net.UnknownHostException;@Configuration
@ComponentScan({"cn.hutool.extra.spring"})
public class RedisConfig {@BeanRedisMessageListenerContainer container (RedisConnectionFactory redisConnectionFactory){RedisMessageListenerContainer container = new RedisMessageListenerContainer();container.setConnectionFactory(redisConnectionFactory);return  container;}@Beanpublic RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {RedisTemplate<String, Object> template = new RedisTemplate();// 连接工厂template.setConnectionFactory(redisConnectionFactory);// 序列化配置Jackson2JsonRedisSerializer objectJackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);ObjectMapper objectMapper = new ObjectMapper();objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);objectJackson2JsonRedisSerializer.setObjectMapper(objectMapper);StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();// 配置具体序列化// key采用string的序列化方式template.setKeySerializer(stringRedisSerializer);// hash的key采用string的序列化方式template.setHashKeySerializer(stringRedisSerializer);// value序列化采用jacksontemplate.setValueSerializer(objectJackson2JsonRedisSerializer);// hash的value序列化采用jacksontemplate.setHashValueSerializer(objectJackson2JsonRedisSerializer);template.afterPropertiesSet();return template;}
}

RedisUtil.java

import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;@Slf4j
@Component
public class RedisUtil {@Resourceprivate RedisTemplate redisTemplate;/*** 消息发送* @param topic 主题* @param message 消息*/public void publish(String topic, String message) {redisTemplate.convertAndSend(topic, message);}
}

application.yml

server:port: 7077
spring:application:name: redis-demoredis:host: localhosttimeout: 3000jedis:pool:max-active: 300max-idle: 100max-wait: 10000port: 6379

RedisController.java

import org.springframework.web.bind.annotation.*;
import javax.annotation.Resource;/*** @author Lux Sun* @date 2023/9/12*/
@RestController
@RequestMapping("/redis")
public class RedisController {@Resourceprivate RedisUtil redisUtil;@PostMappingpublic String publish(@RequestParam String topic, @RequestParam String msg) {redisUtil.publish(topic, msg);return "发送成功: " + topic + " - " + msg;}
}

一、业务情景：1 个消费者监听 1 个 Topic

教程三步走（下文业务情景类似不再描述）

1. 实现接口 MessageListener
2. 消息订阅，绑定业务 Topic
3. 重写 onMessage 消费者业务方法

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Bean;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.listener.PatternTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.data.redis.listener.adapter.MessageListenerAdapter;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;@Slf4j
@Component
public class RedisReceiver1 implements MessageListener {@Resourceprivate RedisMessageListenerContainer container;/*** 重点关注这方法, 进行消息订阅*/@PostConstructpublic void init() {MessageListenerAdapter adapter = new MessageListenerAdapter(this);// 绑定 Topic 语法为正则表达式container.addMessageListener(adapter, new PatternTopic("topic1.*"));}@Overridepublic void onMessage(Message message, byte[] bytes) {String key = new String(message.getChannel());String value = new String(message.getBody());log.info("Key: {}", key);log.info("Value: {}", value);}
}

测试

curl --location '127.0.0.1:7077/redis' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'topic=topic1.msg' \
--data-urlencode 'msg=我是消息1'

结果

2023-11-15 10:22:38.445  INFO 59189 --- [    container-2] com.xxx.redis.demo.RedisReceiver1  : Key: topic1.msg
2023-11-15 10:22:38.445  INFO 59189 --- [    container-2] com.xxx.redis.demo.RedisReceiver1  : Value: "我是消息1"

二、业务情景：1 个消费者监听 N 个 Topic

import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.listener.PatternTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.data.redis.listener.adapter.MessageListenerAdapter;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
import javax.annotation.Resource;@Slf4j
@Component
public class RedisReceiver1 implements MessageListener {@Resourceprivate RedisMessageListenerContainer container;/*** 重点关注这方法, 进行消息订阅*/@PostConstructpublic void init() {MessageListenerAdapter adapter = new MessageListenerAdapter(this);// 绑定 Topic 语法为正则表达式container.addMessageListener(adapter, new PatternTopic("topic1.*"));// 只需再绑定业务 Topic 即可container.addMessageListener(adapter, new PatternTopic("topic2.*"));}@Overridepublic void onMessage(Message message, byte[] bytes) {String key = new String(message.getChannel());String value = new String(message.getBody());log.info("Key: {}", key);log.info("Value: {}", value);}
}

测试

curl --location '127.0.0.1:7077/redis' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'topic=topic2.msg' \
--data-urlencode 'msg=我是消息2'

结果

2023-11-15 10:22:38.445  INFO 59189 --- [    container-2] com.xxx.redis.demo.RedisReceiver1  : Key: topic2.msg
2023-11-15 10:22:38.445  INFO 59189 --- [    container-2] com.xxx.redis.demo.RedisReceiver1  : Value: "我是消息2"

三、业务情景：N 个消费者监听 1 个 Topic

我们看一下，现在又新增一个 RedisReceiver2，按理讲测试的时候，RedisReceiver1 和 RedisReceiver2 会同时收到消息

import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.listener.PatternTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.data.redis.listener.adapter.MessageListenerAdapter;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
import javax.annotation.Resource;@Slf4j
@Component
public class RedisReceiver2 implements MessageListener {@Resourceprivate RedisMessageListenerContainer container;/*** 重点关注这方法, 进行消息订阅*/@PostConstructpublic void init() {MessageListenerAdapter adapter = new MessageListenerAdapter(this);// 绑定 Topic 语法为正则表达式container.addMessageListener(adapter, new PatternTopic("topic1.*"));}@Overridepublic void onMessage(Message message, byte[] bytes) {String key = new String(message.getChannel());String value = new String(message.getBody());log.info("Key: {}", key);log.info("Value: {}", value);}
}

测试

curl --location '127.0.0.1:7077/redis' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'topic=topic1.msg' \
--data-urlencode 'msg=我是消息1'

结果

2023-11-15 10:22:38.445  INFO 59189 --- [    container-2] com.xxx.redis.demo.RedisReceiver1  : Key: topic1.msg
2023-11-15 10:22:38.449  INFO 59189 --- [    container-3] com.xxx.redis.demo.RedisReceiver2  : Key: topic1.msg
2023-11-15 10:22:38.545  INFO 59189 --- [    container-2] com.xxx.redis.demo.RedisReceiver1  : Value: "我是消息1"
2023-11-15 10:22:38.645  INFO 59189 --- [    container-3] com.xxx.redis.demo.RedisReceiver2  : Value: "我是消息1"

四、业务情景：N 个消费者监听 N 个 Topic

都到这阶段了，应该不难理解了吧~

import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.listener.PatternTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.data.redis.listener.adapter.MessageListenerAdapter;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
import javax.annotation.Resource;@Slf4j
@Component
public class RedisReceiver2 implements MessageListener {@Resourceprivate RedisMessageListenerContainer container;/*** 重点关注这方法, 进行消息订阅*/@PostConstructpublic void init() {MessageListenerAdapter adapter = new MessageListenerAdapter(this);// 绑定 Topic 语法为正则表达式container.addMessageListener(adapter, new PatternTopic("topic1.*"));// 只需再绑定业务 Topic 即可container.addMessageListener(adapter, new PatternTopic("topic2.*"));}@Overridepublic void onMessage(Message message, byte[] bytes) {String key = new String(message.getChannel());String value = new String(message.getBody());log.info("Key: {}", key);log.info("Value: {}", value);}
}

测试

curl --location '127.0.0.1:7077/redis' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'topic=topic2.msg' \
--data-urlencode 'msg=我是消息2'

结果

2023-11-15 10:22:38.445  INFO 59189 --- [    container-2] com.xxx.redis.demo.RedisReceiver1  : Key: topic2.msg
2023-11-15 10:22:38.449  INFO 59189 --- [    container-3] com.xxx.redis.demo.RedisReceiver2  : Key: topic2.msg
2023-11-15 10:22:38.545  INFO 59189 --- [    container-2] com.xxx.redis.demo.RedisReceiver1  : Value: "我是消息2"
2023-11-15 10:22:38.645  INFO 59189 --- [    container-3] com.xxx.redis.demo.RedisReceiver2  : Value: "我是消息2"

好了，Redis 订阅发布的教程到此为止。接下来，我们看下如何用它来替代 Etcd 的业务情景？

这之前，我们先大概聊下 Etcd 的 2 个要点：

1. Etcd 消息事件类型
2. Etcd 持久层数据

那么问题来了，Redis 虽然具备基本的消息订阅发布，但是如何契合 Etcd 的这 2 点特性，我们目前给出对应的解决方案是：

1. 使用 Redis K-V 的 value 作为 Etcd 消息事件类型
2. 使用 MySQL 作为 Etcd 持久层数据：字段 id 随机 UUID、字段 key 对应 Etcd key、字段 value 对应 Etcd value，这样做的一个好处是无需重构数据结构

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;DROP TABLE IF EXISTS `t_redis_msg`;
CREATE TABLE `t_redis_msg` (
`id` varchar(32) NOT NULL,
`key` varchar(255) NOT NULL,
`value` longtext,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;SET FOREIGN_KEY_CHECKS = 1;

所以，如果想平替 Etcd 的事件类型和持久层数据的解决方案需要 MySQL & Redis 结合，接下来直接上代码……

Redis & MySQL 整合

application.yml（升级）

spring:application:name: redis-demodatasource:username: rootpassword: 123456url: jdbc:mysql://localhost:3306/db_demo?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=Asia/Shanghaidriver-class-name: com.mysql.cj.jdbc.Driverhikari:connection-test-query: SELECT 1idle-timeout: 40000max-lifetime: 1880000connection-timeout: 40000minimum-idle: 1validation-timeout: 60000maximum-pool-size: 20

RedisMsg.java

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.experimental.SuperBuilder;/*** @author Lux Sun* @date 2021/2/19*/
@Data
@SuperBuilder
@NoArgsConstructor
@AllArgsConstructor
@TableName(value = "t_redis_msg", autoResultMap = true)
public class RedisMsg {@TableId(type = IdType.ASSIGN_UUID)private String id;@TableField(value = "`key`")private String key;private String value;
}

RedisMsgEnum.java

/*** @author Lux Sun* @date 2022/11/11*/
public enum RedisMsgEnum {PUT("PUT"),DEL("DEL");private String code;RedisMsgEnum(String code) {this.code = code;}public String getCode() {return code;}}

RedisMsgService.java

import com.baomidou.mybatisplus.extension.service.IService;
import java.util.List;
import java.util.Map;/*** @author Lux Sun* @date 2020/6/16*/
public interface RedisMsgService extends IService<RedisMsg> {/*** 获取消息* @param key*/RedisMsg get(String key);/*** 获取消息列表* @param key*/Map<String, String> map(String key);/*** 获取消息值* @param key*/String getValue(String key);/*** 获取消息列表* @param key*/List<RedisMsg> list(String key);/*** 插入消息* @param key* @param value*/void put(String key, String value);/*** 删除消息* @param key*/void del(String key);
}

RedisMsgServiceImpl.java

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import javax.annotation.Resource;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;/*** @author Lux Sun* @date 2020/6/16*/
@Slf4j
@Service
public class RedisMsgServiceImpl extends ServiceImpl<RedisMsgDao, RedisMsg> implements RedisMsgService {@Resourceprivate RedisMsgDao redisMsgDao;@Resourceprivate RedisUtil redisUtil;/*** 获取消息** @param key*/@Overridepublic RedisMsg get(String key) {LambdaQueryWrapper<RedisMsg> lqw = new LambdaQueryWrapper<>();lqw.eq(RedisMsg::getKey, key);return redisMsgDao.selectOne(lqw);}/*** 获取消息列表** @param key*/@Overridepublic Map<String, String> map(String key) {List<RedisMsg> redisMsgs = this.list(key);return redisMsgs.stream().collect(Collectors.toMap(RedisMsg::getKey, RedisMsg::getValue));}/*** 获取消息值** @param key*/@Overridepublic String getValue(String key) {RedisMsg redisMsg = this.get(key);return redisMsg.getValue();}/*** 获取消息列表** @param key*/@Overridepublic List<RedisMsg> list(String key) {LambdaQueryWrapper<RedisMsg> lqw = new LambdaQueryWrapper<>();lqw.likeRight(RedisMsg::getKey, key);return redisMsgDao.selectList(lqw);}/*** 插入消息** @param key* @param value*/@Overridepublic void put(String key, String value) {log.info("开始添加 - key: {}，value: {}", key, value);LambdaQueryWrapper<RedisMsg> lqw = new LambdaQueryWrapper<>();lqw.eq(RedisMsg::getKey, key);this.saveOrUpdate(RedisMsg.builder().key(key).value(value).build(), lqw);redisUtil.putMsg(key);log.info("添加成功 - key: {}，value: {}", key, value);}/*** 删除消息** @param key*/@Overridepublic void del(String key) {log.info("开始删除 - key: {}", key);LambdaQueryWrapper<RedisMsg> lqw = new LambdaQueryWrapper<>();lqw.likeRight(RedisMsg::getKey, key);redisMsgDao.delete(lqw);redisUtil.delMsg(key);log.info("删除成功 - key: {}", key);}
}

RedisUtil.java（升级）

import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;@Slf4j
@Component
public class RedisUtil {@Resourceprivate RedisTemplate redisTemplate;/*** 消息发送* @param topic 主题* @param message 消息*/public void publish(String topic, String message) {redisTemplate.convertAndSend(topic, message);}/*** 消息发送 PUT* @param topic 主题*/public void putMsg(String topic) {redisTemplate.convertAndSend(topic, RedisMsgEnum.PUT);}/*** 消息发送 DELETE* @param topic 主题*/public void delMsg(String topic) {redisTemplate.convertAndSend(topic, RedisMsgEnum.DEL);}
}

演示 DEMO

RedisMsgController.java

import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;/*** @author Lux Sun* @date 2023/9/12*/
@RestController
@RequestMapping("/redisMsg")
public class RedisMsgController {@Resourceprivate RedisMsgService redisMsgService;@PostMappingpublic String publish(@RequestParam String topic, @RequestParam String msg) {redisMsgService.put(topic, msg);return "发送成功: " + topic + " - " + msg;}
}

RedisMsgReceiver.java

import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.listener.PatternTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.data.redis.listener.adapter.MessageListenerAdapter;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
import javax.annotation.Resource;@Slf4j
@Component
public class RedisMsgReceiver implements MessageListener {@Resourceprivate RedisMsgService redisMsgService;@Resourceprivate RedisMessageListenerContainer container;@PostConstructpublic void init() {MessageListenerAdapter adapter = new MessageListenerAdapter(this);container.addMessageListener(adapter, new PatternTopic("topic3.*"));}@Overridepublic void onMessage(Message message, byte[] bytes) {String key = new String(message.getChannel());String event = new String(message.getBody());String value = redisMsgService.getValue(key);log.info("Key: {}", key);log.info("Event: {}", event);log.info("Value: {}", value);}
}

测试

curl --location '127.0.0.1:7077/redisMsg' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'topic=topic3.msg' \
--data-urlencode 'msg=我是消息3'

结果

2023-11-16 10:24:35.721  INFO 43794 --- [nio-7077-exec-1] c.c.redis.demo.RedisMsgServiceImpl       : 开始添加 - key: topic3.msg，value: 我是消息3
2023-11-16 10:24:35.935  INFO 43794 --- [nio-7077-exec-1] c.c.redis.demo.RedisMsgServiceImpl       : 添加成功 - key: topic3.msg，value: 我是消息3
2023-11-16 10:24:35.950  INFO 43794 --- [    container-2] c.xxx.redis.demo.RedisMsgReceiver  : Key: topic3.msg
2023-11-16 10:24:35.950  INFO 43794 --- [    container-2] c.xxx.redis.demo.RedisMsgReceiver  : Event: "PUT"
2023-11-16 10:24:35.950  INFO 43794 --- [    container-2] c.xxx.redis.demo.RedisMsgReceiver  : Value: 我是消息3