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SpringBoot2.X与redis Lettuce集成踩坑

起因

最近项目上发现一个问题,redis cluster集群有一台机崩了之后,后台服务的redis会一直报错,无法连接到redis集群。通过命令查看redis集群,发现redis cluster集群是正常的,备用的slave机器已经升级为master。
于是初步猜测是spring-redis的连接池框架在redis的其中一台master机器崩了之后,并没有刷新连接池的连接,仍然连接的是挂掉的那台redis服务器。

通过寻找资料,发现springboot在1.x使用的是jedis框架,在2.x改为默认使用Lettuce框架与redis连接。 在Lettuce官方文档中找到了关于Redis Cluster的相关信息 《Refreshing the cluster topology view》

这里面的大概意思是 自适应拓扑刷新(Adaptive updates)与定时拓扑刷新(Periodic updates) 是默认关闭的,可以通过代码打开。

开搞

继续查找,发现了Lettuce官方给了开启拓扑刷新的代码例子

# Example 37. Enabling periodic cluster topology view updates
RedisClusterClient clusterClient = RedisClusterClient.create(RedisURI.create("localhost", 6379));

ClusterTopologyRefreshOptions topologyRefreshOptions = ClusterTopologyRefreshOptions.builder()
                                .enablePeriodicRefresh(10, TimeUnit.MINUTES)
                                .build();

clusterClient.setOptions(ClusterClientOptions.builder()
                                .topologyRefreshOptions(topologyRefreshOptions)
                                .build());
...

clusterClient.shutdown();


# Example 38. Enabling adaptive cluster topology view updates
RedisURI node1 = RedisURI.create("node1", 6379);
RedisURI node2 = RedisURI.create("node2", 6379);

RedisClusterClient clusterClient = RedisClusterClient.create(Arrays.asList(node1, node2));

ClusterTopologyRefreshOptions topologyRefreshOptions = ClusterTopologyRefreshOptions.builder()
                                .enableAdaptiveRefreshTrigger(RefreshTrigger.MOVED_REDIRECT, RefreshTrigger.PERSISTENT_RECONNECTS)
                                .adaptiveRefreshTriggersTimeout(30, TimeUnit.SECONDS)
                                .build();

clusterClient.setOptions(ClusterClientOptions.builder()
                                .topologyRefreshOptions(topologyRefreshOptions)
                                .build());
...

clusterClient.shutdown();
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根据示例我们修改一下我们的项目代码

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import io.lettuce.core.cluster.ClusterClientOptions;
import io.lettuce.core.cluster.ClusterTopologyRefreshOptions;
import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.data.redis.RedisProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisClusterConfiguration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.RedisNode;
import org.springframework.data.redis.connection.RedisPassword;
import org.springframework.data.redis.connection.lettuce.LettuceClientConfiguration;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.connection.lettuce.LettucePoolingClientConfiguration;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;


import java.time.Duration;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

@Configuration
public class LettuceRedisConfig {


    @Autowired
    private RedisProperties redisProperties;

    /**
     * 配置RedisTemplate
     * 【Redis配置最终一步】
     *
     * @param lettuceConnectionFactoryUvPv redis连接工厂实现
     * @return 返回一个可以使用的RedisTemplate实例
     */
    @Bean
    public RedisTemplate redisTemplate(@Qualifier("lettuceConnectionFactoryUvPv") RedisConnectionFactory lettuceConnectionFactoryUvPv) {
        RedisTemplate<String, Object> template = new RedisTemplate<String, Object>();
        template.setConnectionFactory(lettuceConnectionFactoryUvPv);
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);
        StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
        // key采用String的序列化方式
        template.setKeySerializer(stringRedisSerializer);
        // hash的key也采用String的序列化方式
        template.setHashKeySerializer(stringRedisSerializer);
        // value序列化方式采用jackson
        template.setValueSerializer(jackson2JsonRedisSerializer);
        // hash的value序列化方式采用jackson
        template.setHashValueSerializer(jackson2JsonRedisSerializer);
        template.afterPropertiesSet();
        return template;
    }


    /**
     * 为RedisTemplate配置Redis连接工厂实现
     * LettuceConnectionFactory实现了RedisConnectionFactory接口
     * UVPV用Redis
     *
     * @return 返回LettuceConnectionFactory
     */
    @Bean(destroyMethod = "destroy")
    //这里要注意的是,在构建LettuceConnectionFactory 时,如果不使用内置的destroyMethod,可能会导致Redis连接早于其它Bean被销毁
    public LettuceConnectionFactory lettuceConnectionFactoryUvPv() throws Exception {

        List<String> clusterNodes = redisProperties.getCluster().getNodes();
        Set<RedisNode> nodes = new HashSet<RedisNode>();
        clusterNodes.forEach(address -> nodes.add(new RedisNode(address.split(":")[0].trim(), Integer.valueOf(address.split(":")[1]))));
        RedisClusterConfiguration clusterConfiguration = new RedisClusterConfiguration();
        clusterConfiguration.setClusterNodes(nodes);
        clusterConfiguration.setPassword(RedisPassword.of(redisProperties.getPassword()));
        clusterConfiguration.setMaxRedirects(redisProperties.getCluster().getMaxRedirects());

        GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();
        poolConfig.setMaxIdle(redisProperties.getLettuce().getPool().getMaxIdle());
        poolConfig.setMinIdle(redisProperties.getLettuce().getPool().getMinIdle());
        poolConfig.setMaxTotal(redisProperties.getLettuce().getPool().getMaxActive());

        return new LettuceConnectionFactory(clusterConfiguration, getLettuceClientConfiguration(poolConfig));
    }

    /**
     * 配置LettuceClientConfiguration 包括线程池配置和安全项配置
     *
     * @param genericObjectPoolConfig common-pool2线程池
     * @return lettuceClientConfiguration
     */
    private LettuceClientConfiguration getLettuceClientConfiguration(GenericObjectPoolConfig genericObjectPoolConfig) {
        /*
        ClusterTopologyRefreshOptions配置用于开启自适应刷新和定时刷新。如自适应刷新不开启,Redis集群变更时将会导致连接异常!
         */
        ClusterTopologyRefreshOptions topologyRefreshOptions = ClusterTopologyRefreshOptions.builder()
                //开启自适应刷新
                //.enableAdaptiveRefreshTrigger(ClusterTopologyRefreshOptions.RefreshTrigger.MOVED_REDIRECT, ClusterTopologyRefreshOptions.RefreshTrigger.PERSISTENT_RECONNECTS)
                //开启所有自适应刷新,MOVED,ASK,PERSISTENT都会触发
                .enableAllAdaptiveRefreshTriggers()
                // 自适应刷新超时时间(默认30秒)
                .adaptiveRefreshTriggersTimeout(Duration.ofSeconds(25)) //默认关闭开启后时间为30秒
                // 开周期刷新
                .enablePeriodicRefresh(Duration.ofSeconds(20))  // 默认关闭开启后时间为60秒 ClusterTopologyRefreshOptions.DEFAULT_REFRESH_PERIOD 60  .enablePeriodicRefresh(Duration.ofSeconds(2)) = .enablePeriodicRefresh().refreshPeriod(Duration.ofSeconds(2))
                .build();
        return LettucePoolingClientConfiguration.builder()
                .poolConfig(genericObjectPoolConfig)
                .clientOptions(ClusterClientOptions.builder().topologyRefreshOptions(topologyRefreshOptions).build())
                //将appID传入连接,方便Redis监控中查看
                //.clientName(appName + "_lettuce")
                .build();
    }
}
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之后在工具类中注入redisTemplate类即可

    @Autowired
    private RedisTemplate<String, Object> redisTemplate;
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稍微深入了解一下

我们可以通过debug断点查看redisTemplate类的参数来观察拓扑刷新是否开启,在未设置之前,我们的redisTemplate的周期刷新和拓扑刷新都是false

在设置了开启拓扑刷新之后,可以看到我们的两个参数值都变成了true

其中clusterTopologyRefreshActivated参数并不是根据我们增加的拓扑刷新开启就初始化为true的,它是在第一次使用redisTemplate的时候,在RedisClusterClient#activateTopologyRefreshIfNeeded方法中修改为true的,有兴趣的可以自行debug跟踪一下。

不用Lettuce,使用回Jedis

当然,如果你想就此放弃Lettuce转用jedis也是可以的。在Spring Boot2.X版本,只要在pom.xml里,调整一下依赖包的引用即可:

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-redis</artifactId>
			<exclusions>
				<exclusion>
					<groupId>io.lettuce</groupId>
					<artifactId>lettuce-core</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
		
		<dependency>
			<groupId>redis.clients</groupId>
			<artifactId>jedis</artifactId>
		</dependency>
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配置上lettuce换成jedis的,既可以完成底层对jedis的替换

spring:
  redis:
    jedis:
      pool:
        max-active: ${redis.config.maxTotal:1024}
        max-idle: ${redis.config.maxIdle:50}
        min-idle: ${redis.config.minIdle:1}
        max-wait: ${redis.config.maxWaitMillis:5000}
    #lettuce:
      #pool:
        #max-active: ${redis.config.maxTotal:1024}
        #max-idle: ${redis.config.maxIdle:50}
        #min-idle: ${redis.config.minIdle:1}
        #max-wait: ${redis.config.maxWaitMillis:5000}
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Jedis和Lettuce区别

Lettuce相较于Jedis有哪些优缺点?

Lettuce 和 Jedis 的定位都是Redis的client,所以他们当然可以直接连接redis server。

Jedis在实现上是直接连接的redis server,如果在多线程环境下是非线程安全的,这个时候只有使用连接池,为每个Jedis实例增加物理连接

Lettuce的连接是基于Netty的,连接实例(StatefulRedisConnection)可以在多个线程间并发访问,应为StatefulRedisConnection是线程安全的,所以一个连接实例(StatefulRedisConnection)就可以满足多线程环境下的并发访问,当然这个也是可伸缩的设计,一个连接实例不够的情况也可以按需增加连接实例。