Spring Boot：配置 Redis 集群

Note：基于 Spring Boot 2.7.6 版本。

spring:
  redis:
    cluster:
      nodes:
        - YOUR.HOSTNAME:6371
        - YOUR.HOSTNAME:6372
        - YOUR.HOSTNAME:6373
        - YOUR.HOSTNAME:6374
        - YOUR.HOSTNAME:6375
        - YOUR.HOSTNAME:6376
      max-redirects: 3
    lettuce:
      cluster:
        refresh:
          adaptive: true # Proactively refresh the Redis cluster topology
          period: 2000
      pool:
        enabled: true # Ensure connection pooling is enabled
        max-active: 16
        max-idle: 8
        min-idle: 2
        max-wait: -1ms
    username: YOUR_USERNAME
    password: YOUR_PASSWORD

Spring Boot 2.7.6 Lettuce 连接池依赖 commons-pool2。当类路径中存在 commons-pool2 时，将自动启用连接池。否则，即使声明了 spring.redis.lettuce.pool.enabled = true 也将在项目运行时引发异常。

<!-- Commons Pool2 -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-pool2</artifactId>
</dependency>

为了让 Lettuce 客户端在进行读操作时，优先从从节点（Replica）读取数据，而不是从主节点（Master）读取数据，可以自定义 Lettuce 客户端的读取策略：

@Configuration
public class RedisConfiguration {
    @Bean
    public LettuceClientConfigurationBuilderCustomizer clientConfigurationBuilderCustomizer() {
        return builder -> builder.readFrom(ReadFrom.REPLICA_PREFERRED);
    }
}