生产用途

让您的 Lettuce 应用程序为生产做好准备

以下各节说明如何处理可能发生的情况 在您的生产环境中。

超时

Lettuce 为许多作提供超时，例如命令执行、SSL 握手和 Sentinel 发现。默认情况下，Lettuce 对这些作使用 60 秒的全局超时值，但您可以使用每个作的单独超时值覆盖全局超时值。

提示：
选择合适的超时值对于应用程序的性能和稳定性至关重要，并且特定于每个环境。 仅当默认值有问题时，才需要配置超时。 在某些情况下，默认值基于特定于环境的设置（例如，作系统设置），而在其他情况下，它们内置于 Lettuce 驱动程序中。 有关设置特定超时的更多详细信息，请参阅 Lettuce 参考指南。

下面是设置 socket-level timeouts 的示例。这TCP_USER_TIMEOUT设置可用于服务器在不确认最后一个请求的情况下停止响应的情况，而KEEPALIVE设置适用于检测客户端和服务器之间没有流量的死连接。

RedisURI redisURI = RedisURI.Builder
        .redis("localhost")
        // set the global default from the default 60 seconds to 30 seconds
        .withTimeout(Duration.ofSeconds(30)) 
        .build();

try (RedisClient client = RedisClient.create(redisURI)) {
    // or set specific timeouts for things such as the TCP_USER_TIMEOUT and TCP_KEEPALIVE

    // A good general rule of thumb is to follow the rule
    // TCP_USER_TIMEOUT = TCP_KEEP_IDLE+TCP_KEEPINTVL * TCP_KEEPCNT
    // in this case, 20 = 5 + 5 * 3

    SocketOptions.TcpUserTimeoutOptions tcpUserTimeout = SocketOptions.TcpUserTimeoutOptions.builder()
            .tcpUserTimeout(Duration.ofSeconds(20))
            .enable().build();

    SocketOptions.KeepAliveOptions keepAliveOptions = SocketOptions.KeepAliveOptions.builder()
            .interval(Duration.ofSeconds(5))
            .idle(Duration.ofSeconds(5))
            .count(3).enable().build();

    SocketOptions socketOptions = SocketOptions.builder()
            .tcpUserTimeout(tcpUserTimeout)
            .keepAlive(keepAliveOptions)
            .build();

    client.setOptions(ClientOptions.builder()
            .socketOptions(socketOptions)
            .build());

    StatefulRedisConnection<String, String> connection = client.connect();
    System.out.println(connection.sync().ping());
}

Cluster topology refresh

The Redis Cluster configuration is dynamic and can change at runtime. New nodes may be added, and the primary node for a specific slot can shift. Lettuce automatically handles MOVED and ASK redirects, but to enhance your application's resilience, you should enable adaptive topology refreshing:

RedisURI redisURI = RedisURI.Builder
        .redis("localhost")
        // set the global default from the default 60 seconds to 30 seconds
        .withTimeout(Duration.ofSeconds(30)) 
        .build();
        
// Create a RedisClusterClient with adaptive topology refresh
try (RedisClusterClient clusterClient = RedisClusterClient.create(redisURI)) {
    // Enable TCP keep-alive and TCP user timeout just like in the standalone example
    SocketOptions.TcpUserTimeoutOptions tcpUserTimeout = SocketOptions.TcpUserTimeoutOptions.builder()
            .tcpUserTimeout(Duration.ofSeconds(20))
            .enable()
            .build();

    SocketOptions.KeepAliveOptions keepAliveOptions = SocketOptions.KeepAliveOptions.builder()
            .interval(Duration.ofSeconds(5))
            .idle(Duration.ofSeconds(5))
            .count(3)
            .enable()
            .build();

    SocketOptions socketOptions = SocketOptions.builder()
            .tcpUserTimeout(tcpUserTimeout)
            .keepAlive(keepAliveOptions)
            .build();

    // Enable adaptive topology refresh
    // Configure adaptive topology refresh options
    ClusterTopologyRefreshOptions topologyRefreshOptions = ClusterTopologyRefreshOptions.builder()
            .enableAllAdaptiveRefreshTriggers()
            .adaptiveRefreshTriggersTimeout(Duration.ofSeconds(30))
            .build();
    
    ClusterClientOptions options = ClusterClientOptions.builder()
            .topologyRefreshOptions(topologyRefreshOptions)
            .socketOptions(socketOptions).build();

    clusterClient.setOptions(options);

    StatefulRedisClusterConnection<String, String> connection = clusterClient.connect();
    System.out.println(connection.sync().ping());
    connection.close();
}

Learn more about topology refresh configuration settings in the reference guide.

DNS cache and Redis

When you connect to a Redis server with multiple endpoints, such as Redis Enterprise Active-Active, you must disable the JVM's DNS cache. If a server node or proxy fails, the IP address for any database affected by the failure will change. When this happens, your app will keep trying to use the stale IP address if DNS caching is enabled.

Use the following code to disable the DNS cache:

java.security.Security.setProperty("networkaddress.cache.ttl","0");
java.security.Security.setProperty("networkaddress.cache.negative.ttl", "0");
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