常见Redis使用问题

一 lettuce使用问题

1 问题描述

Redis Cluster集群，当master宕机，主从切换，客户端报错 timed out

2 原因

SpringBoot2.X版本开始Redis默认的连接池都是采用的Lettuce。当节点发生改变后，Letture默认是不会刷新节点拓扑的。

3 解决方案

3.1 方案一：把lettuce换成jedis

推荐版本：jedis 2.9+
只需要在pom.xml里调整一下依赖的引用

      <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId><version>2.1.5.RELEASE</version><!-- 不用lettuce ,用jedis --><exclusions><exclusion><groupId>io.lettuce</groupId><artifactId>lettuce-core</artifactId></exclusion></exclusions></dependency><dependency><groupId>redis.clients</groupId><artifactId>jedis</artifactId><version>3.1.0-m4</version></dependency>

3.2 方案二：刷新节点拓扑视图

Redis节点异常，服务端的Redis集群拓扑被刷新了，Java程序没有获取到新的拓扑。
Lettuce官方文档中关于Redis Cluster的相关说明：Lettuce处理Moved和Ask永久重定向，由于命令重定向，你必须刷新节点拓扑视图。而自适应拓扑刷新（Adaptive updates）与定时拓扑刷新（Periodic updates）是默认关闭的，可以通过如下代码打开。
https://github.com/lettuce-io/lettuce-core/wiki/Redis-Cluster#user-content-refreshing-the-cluster-topology-view
在这里插入图片描述

修改代码如下

package com.montnets.common.redis;import io.lettuce.core.ClientOptions;
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.boot.autoconfigure.data.redis.RedisProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.data.redis.connection.RedisClusterConfiguration;
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.stereotype.Component;import java.time.Duration;
import java.util.HashSet;
import java.util.List;
import java.util.Set;@Component
public class RedisPoolConfig {@Autowiredprivate RedisProperties redisProperties;public GenericObjectPoolConfig<?> genericObjectPoolConfig(RedisProperties.Pool properties) {GenericObjectPoolConfig<?> config = new GenericObjectPoolConfig<>();config.setMaxTotal(properties.getMaxActive());config.setMaxIdle(properties.getMaxIdle());config.setMinIdle(properties.getMinIdle());if (properties.getTimeBetweenEvictionRuns() != null) {config.setTimeBetweenEvictionRunsMillis(properties.getTimeBetweenEvictionRuns().toMillis());}if (properties.getMaxWait() != null) {config.setMaxWaitMillis(properties.getMaxWait().toMillis());}return config;}@Bean(destroyMethod = "destroy")public LettuceConnectionFactory lettuceConnectionFactory() {//开启 自适应集群拓扑刷新和周期拓扑刷新ClusterTopologyRefreshOptions clusterTopologyRefreshOptions =  ClusterTopologyRefreshOptions.builder()// 开启全部自适应刷新.enableAllAdaptiveRefreshTriggers() // 开启自适应刷新,自适应刷新不开启,Redis集群变更时将会导致连接异常// 自适应刷新超时时间(默认30秒).adaptiveRefreshTriggersTimeout(Duration.ofSeconds(30)) //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();// https://github.com/lettuce-io/lettuce-core/wiki/Client-OptionsClientOptions clientOptions = ClusterClientOptions.builder().topologyRefreshOptions(clusterTopologyRefreshOptions).build();LettuceClientConfiguration clientConfig = LettucePoolingClientConfiguration.builder().poolConfig(genericObjectPoolConfig(redisProperties.getJedis().getPool()))//.readFrom(ReadFrom.MASTER_PREFERRED).clientOptions(clientOptions).commandTimeout(redisProperties.getTimeout()) //默认RedisURI.DEFAULT_TIMEOUT 60.build();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());LettuceConnectionFactory lettuceConnectionFactory = new LettuceConnectionFactory(clusterConfiguration, clientConfig);// lettuceConnectionFactory.setShareNativeConnection(false); //是否允许多个线程操作共用同一个缓存连接，默认true，false时每个操作都将开辟新的连接// lettuceConnectionFactory.resetConnection(); // 重置底层共享连接, 在接下来的访问时初始化return lettuceConnectionFactory;}
}