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 {

    @Bean
    RedisMessageListenerContainer container (RedisConnectionFactory redisConnectionFactory){
        RedisMessageListenerContainer container = new RedisMessageListenerContainer();
        container.setConnectionFactory(redisConnectionFactory);
        return  container;
    }
    
    @Bean
    public 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jackson
        template.setValueSerializer(objectJackson2JsonRedisSerializer);
        // hash的value序列化采用jackson
        template.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 {

    @Resource
    private 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-demo
  redis:
    host: localhost
    timeout: 3000
    jedis:
      pool:
        max-active: 300
        max-idle: 100
        max-wait: 10000
    port: 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 {

    @Resource
    private RedisUtil redisUtil;
    
    @PostMapping
    public 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 {

    @Resource
    private RedisMessageListenerContainer container;

    /**
     * 重点关注这方法, 进行消息订阅
     */
    @PostConstruct
    public void init() {
        MessageListenerAdapter adapter = new MessageListenerAdapter(this);
        // 绑定 Topic 语法为正则表达式
        container.addMessageListener(adapter, new PatternTopic("topic1.*"));
    }

    @Override
    public 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 {

    @Resource
    private RedisMessageListenerContainer container;

    /**
     * 重点关注这方法, 进行消息订阅
     */
    @PostConstruct
    public 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.*"));
    }

    @Override
    public 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 {

    @Resource
    private RedisMessageListenerContainer container;

    /**
     * 重点关注这方法, 进行消息订阅
     */
    @PostConstruct
    public void init() {
        MessageListenerAdapter adapter = new MessageListenerAdapter(this);
        // 绑定 Topic 语法为正则表达式
        container.addMessageListener(adapter, new PatternTopic("topic1.*"));
    }

    @Override
    public 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 {

    @Resource
    private RedisMessageListenerContainer container;

    /**
     * 重点关注这方法, 进行消息订阅
     */
    @PostConstruct
    public 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.*"));
    }

    @Override
    public 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-demo
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/db_demo?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=Asia/Shanghai
    driver-class-name: com.mysql.cj.jdbc.Driver
    hikari:
      connection-test-query: SELECT 1
      idle-timeout: 40000
      max-lifetime: 1880000
      connection-timeout: 40000
      minimum-idle: 1
      validation-timeout: 60000
      maximum-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 {

    @Resource
    private RedisMsgDao redisMsgDao;

    @Resource
    private RedisUtil redisUtil;

    /**
     * 获取消息
     *
     * @param key
     */
    @Override
    public 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
     */
    @Override
    public 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
     */
    @Override
    public String getValue(String key) {
        RedisMsg redisMsg = this.get(key);
        return redisMsg.getValue();
    }

    /**
     * 获取消息列表
     *
     * @param key
     */
    @Override
    public 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
     */
    @Override
    public 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
     */
    @Override
    public 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 {

    @Resource
    private 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 {

    @Resource
    private RedisMsgService redisMsgService;

    @PostMapping
    public 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 {

    @Resource
    private RedisMsgService redisMsgService;

    @Resource
    private RedisMessageListenerContainer container;

    @PostConstruct
    public void init() {
        MessageListenerAdapter adapter = new MessageListenerAdapter(this);
        container.addMessageListener(adapter, new PatternTopic("topic3.*"));
    }

    @Override
    public 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