Updated on 2024-10-28 GMT+08:00

Connecting to Redis on Redisson (Java)

This section describes how to access a Redis instance on Redisson. For more information about how to use other Redis clients, visit the Redis official website.

For Spring Boot projects, Spring Data Redis is already integrated with Jedis and Lettuce, but does not support Redisson. Redisson provides the redisson-spring-boot-starter component (https://mvnrepository.com/artifact/org.redisson/redisson) that can be used with Spring Boot.

Spring Boot 1.x is integrated with Jedis, and Spring Boot 2.x is integrated with Lettuce.

  • If a password was set during DCS Redis instance creation, configure the password for connecting to Redis using Redisson. Do not hard code the plaintext password.
  • To connect to a single-node, read/write splitting, or Proxy Cluster instance, use the useSingleServer method of the SingleServerConfig object of Redisson. To connect to a master/standby instance, use the useMasterSlaveServers method of the MasterSlaveServersConfig object of Redisson. To connect to a Redis Cluster instance, use the useClusterServers method of the ClusterServersConfig object.
  • Springboot 2.3.12.RELEASE or later is required. Redisson 3.37.0 or later is required.

Prerequisites

Pom Configuration

<!-- spring-data-redis -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
    <exclusions>
        <!--Lettuce is integrated in Spring Boot 2.x by default. This dependency needs to be deleted. -->
        <exclusion>
            <artifactId>lettuce-core</artifactId>
            <groupId>io.lettuce</groupId>
        </exclusion>
    </exclusions>
</dependency>
<!--Redisson's adaptation package for Spring Boot-->
<dependency>
    <groupId>org.redisson</groupId>
    <artifactId>redisson-spring-boot-starter</artifactId>
    <version>${redisson.version}</version>
</dependency>

Bean Configuration

Spring Boot does not provide Redisson adaptation, and the application.properties configuration file does not have the corresponding configuration item. Therefore, you can only use Bean configuration.

  • Single-node, read/write splitting, and Proxy Cluster
    import org.redisson.Redisson;
    import org.redisson.api.RedissonClient;
    import org.redisson.codec.JsonJacksonCodec;
    import org.redisson.config.Config;
    import org.redisson.config.SingleServerConfig;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    @Configuration
    public class SingleConfig {
    
        @Value("${redis.address:}")
        private String redisAddress;
    
        @Value("${redis.password:}")
        private String redisPassword;
    
        @Value("${redis.database:0}")
        private Integer redisDatabase = 0;
    
        @Value("${redis.connect.timeout:3000}")
        private Integer redisConnectTimeout = 3000;
    
        @Value("${redis.connection.idle.timeout:10000}")
        private Integer redisConnectionIdleTimeout = 10000;
    
        @Value("${redis.connection.ping.interval:1000}")
        private Integer redisConnectionPingInterval = 1000;
    
        @Value("${redis.timeout:2000}")
        private Integer timeout = 2000;
    
        @Value("${redis.connection.pool.min.size:50}")
        private Integer redisConnectionPoolMinSize;
    
        @Value("${redis.connection.pool.max.size:200}")
        private Integer redisConnectionPoolMaxSize;
    
        @Value("${redis.retry.attempts:3}")
        private Integer redisRetryAttempts = 3;
    
        @Value("${redis.retry.interval:200}")
        private Integer redisRetryInterval = 200;
    
        @Bean
        public RedissonClient redissonClient(){
            Config redissonConfig = new Config();
    
            SingleServerConfig serverConfig = redissonConfig.useSingleServer();
            serverConfig.setAddress(redisAddress);
            serverConfig.setConnectionMinimumIdleSize(redisConnectionPoolMinSize);
            serverConfig.setConnectionPoolSize(redisConnectionPoolMaxSize);
    
            serverConfig.setDatabase(redisDatabase);
            serverConfig.setPassword(redisPassword);
            serverConfig.setConnectTimeout(redisConnectTimeout);
            serverConfig.setIdleConnectionTimeout(redisConnectionIdleTimeout);
            serverConfig.setPingConnectionInterval(redisConnectionPingInterval);
            serverConfig.setTimeout(timeout);
            serverConfig.setRetryAttempts(redisRetryAttempts);
            serverConfig.setRetryInterval(redisRetryInterval);
    
            redissonConfig.setCodec(new JsonJacksonCodec());
            return Redisson.create(redissonConfig);
        }
    }
  • Master/Standby
    import org.redisson.Redisson;
    import org.redisson.api.RedissonClient;
    import org.redisson.codec.JsonJacksonCodec;
    import org.redisson.config.Config;
    import org.redisson.config.MasterSlaveServersConfig;
    import org.redisson.config.ReadMode;
    import org.redisson.config.SubscriptionMode;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    import java.util.HashSet;
    
    @Configuration
    public class MasterStandbyConfig {
        @Value("${redis.master.address}")
        private String redisMasterAddress;
    
        @Value("${redis.slave.address}")
        private String redisSlaveAddress;
    
        @Value("${redis.database:0}")
        private Integer redisDatabase = 0;
    
        @Value("${redis.password:}")
        private String redisPassword;
    
        @Value("${redis.connect.timeout:3000}")
        private Integer redisConnectTimeout = 3000;
    
        @Value("${redis.connection.idle.timeout:10000}")
        private Integer redisConnectionIdleTimeout = 10000;
    
        @Value("${redis.connection.ping.interval:1000}")
        private Integer redisConnectionPingInterval = 1000;
    
        @Value("${redis.timeout:2000}")
        private Integer timeout = 2000;
    
        @Value("${redis.master.connection.pool.min.size:50}")
        private Integer redisMasterConnectionPoolMinSize = 50;
    
        @Value("${redis.master.connection.pool.max.size:200}")
        private Integer redisMasterConnectionPoolMaxSize = 200;
    
        @Value("${redis.retry.attempts:3}")
        private Integer redisRetryAttempts = 3;
    
        @Value("${redis.retry.interval:200}")
        private Integer redisRetryInterval = 200;
    
        @Bean
        public RedissonClient redissonClient() {
            Config redissonConfig = new Config();
    
            MasterSlaveServersConfig serverConfig = redissonConfig.useMasterSlaveServers();
            serverConfig.setMasterAddress(redisMasterAddress);
            HashSet<String> slaveSet = new HashSet<>();
            slaveSet.add(redisSlaveAddress);
            serverConfig.setSlaveAddresses(slaveSet);
    
            serverConfig.setDatabase(redisDatabase);
            serverConfig.setPassword(redisPassword);
    
            serverConfig.setMasterConnectionMinimumIdleSize(redisMasterConnectionPoolMinSize);
            serverConfig.setMasterConnectionPoolSize(redisMasterConnectionPoolMaxSize);
    
            serverConfig.setReadMode(ReadMode.MASTER);
            serverConfig.setSubscriptionMode(SubscriptionMode.MASTER);
    
            serverConfig.setConnectTimeout(redisConnectTimeout);
            serverConfig.setIdleConnectionTimeout(redisConnectionIdleTimeout);
            serverConfig.setPingConnectionInterval(redisConnectionPingInterval);
            serverConfig.setTimeout(timeout);
            serverConfig.setRetryAttempts(redisRetryAttempts);
            serverConfig.setRetryInterval(redisRetryInterval);
    
            redissonConfig.setCodec(new JsonJacksonCodec());
            return Redisson.create(redissonConfig);
        }
    }
  • Redis Cluster
    import org.redisson.Redisson;
    import org.redisson.api.RedissonClient;
    import org.redisson.codec.JsonJacksonCodec;
    import org.redisson.config.ClusterServersConfig;
    import org.redisson.config.Config;
    import org.redisson.config.ReadMode;
    import org.redisson.config.SubscriptionMode;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    import java.util.List;
    
    @Configuration
    public class ClusterConfig {
    
        @Value("${redis.cluster.address}")
        private List<String> redisClusterAddress;
    
        @Value("${redis.cluster.scan.interval:5000}")
        private Integer redisClusterScanInterval = 5000;
    
        @Value("${redis.password:}")
        private String redisPassword;
    
        @Value("${redis.connect.timeout:3000}")
        private Integer redisConnectTimeout = 3000;
    
        @Value("${redis.connection.idle.timeout:10000}")
        private Integer redisConnectionIdleTimeout = 10000;
    
        @Value("${redis.connection.ping.interval:1000}")
        private Integer redisConnectionPingInterval = 1000;
    
        @Value("${redis.timeout:2000}")
        private Integer timeout = 2000;
    
        @Value("${redis.retry.attempts:3}")
        private Integer redisRetryAttempts = 3;
    
        @Value("${redis.retry.interval:200}")
        private Integer redisRetryInterval = 200;
    
        @Value("${redis.master.connection.pool.min.size:50}")
        private Integer redisMasterConnectionPoolMinSize = 50;
    
        @Value("${redis.master.connection.pool.max.size:200}")
        private Integer redisMasterConnectionPoolMaxSize = 200;
    
        @Bean
        public RedissonClient redissonClient() {
            Config redissonConfig = new Config();
    
            ClusterServersConfig serverConfig = redissonConfig.useClusterServers();
            serverConfig.setNodeAddresses(redisClusterAddress);
            serverConfig.setScanInterval(redisClusterScanInterval);
    
            serverConfig.setPassword(redisPassword);
    
            serverConfig.setMasterConnectionMinimumIdleSize(redisMasterConnectionPoolMinSize);
            serverConfig.setMasterConnectionPoolSize(redisMasterConnectionPoolMaxSize);
    
            serverConfig.setReadMode(ReadMode.MASTER);
            serverConfig.setSubscriptionMode(SubscriptionMode.MASTER);
    
            serverConfig.setConnectTimeout(redisConnectTimeout);
            serverConfig.setIdleConnectionTimeout(redisConnectionIdleTimeout);
            serverConfig.setPingConnectionInterval(redisConnectionPingInterval);
            serverConfig.setTimeout(timeout);
            serverConfig.setRetryAttempts(redisRetryAttempts);
            serverConfig.setRetryInterval(redisRetryInterval);
    
            redissonConfig.setCodec(new JsonJacksonCodec());
            return Redisson.create(redissonConfig);
        }
    }

(Optional) Configuring SSL Connections

If SSL is enabled for an instance, to access it using SSL connections, add the configRedissonSSL(serverConfig) logic to the RedissonClient construction method clientConfiguration() in Bean Configuration and change the Redis addresses from redis://ip:port to rediss://ip:port. For details about whether your DCS Redis instances support SSL, see Transmitting DCS Redis Data with Encryption Using SSL.

private void configRedissonSSL(BaseConfig serverConfig) {
    TrustManagerFactory trustManagerFactory = null;
    try {
        //Load the CA certificate in the user-defined path.
        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        Certificate ca;
        try (InputStream is = new FileInputStream(certificationPath)) {
            ca = cf.generateCertificate(is);
        }

        //Create keystore.
        String keyStoreType = KeyStore.getDefaultType();
        KeyStore keyStore = KeyStore.getInstance(keyStoreType);
        keyStore.load(null, null);
        keyStore.setCertificateEntry("ca", ca);

        //Create TrustManager.
        trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
        trustManagerFactory.init(keyStore);
    } catch (CertificateException | IOException | KeyStoreException | NoSuchAlgorithmException e) {
        e.printStackTrace();
        return;
    }

    serverConfig.setSslTrustManagerFactory(trustManagerFactory);
}

Parameter Description

Table 1 Config parameters

Parameter

Default Value

Description

codec

org.redisson.codec.JsonJacksonCodec

Encoding format, including JSON, Avro, Smile, CBOR, and MsgPack.

threads

Number of CPU cores x 2

Thread pool used for executing RTopic Listener, RRemoteService, and RExecutorService.

executor

null

The function is the same as threads. If this parameter is not set, a thread pool is initialized based on threads.

nettyThreads

Number of CPU cores x 2

Thread pool used by the TCP channel that connects to the redis-server. All channels share this connection pool and are mapped to Netty's Bootstrap.group(...).

eventLoopGroup

null

The function is the same as nettyThreads. If this parameter is not set, an EventLoopGroup is initialized based on the nettyThreads parameter for the bottom-layer TCP channel to use.

transportMode

TransportMode.NIO

Transmission mode. The options are NIO, EPOLL (additional package required), and KQUEUE (additional package required).

lockWatchdogTimeout

30000

Timeout interval (in milliseconds) of the lock-monitoring watchdog. In the distributed lock scenario, if the leaseTimeout parameter is not specified, the default value of this parameter is used.

keepPubSubOrder

true

Indicates whether to receive messages in the publish sequence. If messages can be processed concurrently, you are advised to set this parameter to false.

Table 2 SingleServerConfig parameters (single-node, read/write splitting,, or Proxy Cluster)

Parameter

Default Value

Description

address

-

Node connection information, in redis://ip:port format.

database

0

ID of the database to be used.

connectionMinimumIdleSize

32

Minimum number of connections to the master node of each shard.

connectionPoolSize

64

Maximum number of connections to the master node of each shard.

subscriptionConnectionMinimumIdleSize

1

Minimum number of connections to the target node for pub/sub.

subscriptionConnectionPoolSize

50

Maximum number of connections to the target node for pub/sub.

subcriptionPerConnection

5

Maximum number of subscriptions on each subscription connection.

connectionTimeout

10000

Connection timeout interval, in milliseconds.

idleConnectionTimeout

10000

Maximum time (in milliseconds) for reclaiming idle connections.

pingConnectionInterval

30000

Heartbeat for detecting available connections, in milliseconds. Recommended: 3000 ms.

timeout

3000

Timeout interval for waiting for a response, in milliseconds.

retryAttempts

3

Maximum number of retries upon send failures.

retryInterval

1500

Retry interval, in milliseconds. Recommended: 200 ms.

clientName

null

Client name.

Table 3 MasterSlaveServersConfig parameters (master/standby)

Parameter

Default Value

Description

masterAddress

-

Master node connection information, in redis://ip:port format.

slaveAddresses

-

Standby node connection information, in Set<redis://ip:port> format.

readMode

SLAVE

Read mode. By default, read traffic is distributed to replica nodes. The value can be MASTER (recommended), SLAVE, or MASTER_SLAVE. Other values may cause access failures in failover scenarios.

loadBalancer

RoundRobinLoadBalancer

Load balancing algorithm. This parameter is valid only when readMode is set to SLAVE or MASTER_SLAVE. Read traffic is distributed evenly.

masterConnectionMinimumIdleSize

32

Minimum number of connections to the master node of each shard.

masterConnectionPoolSize

64

Maximum number of connections to the master node of each shard.

slaveConnectionMinimumIdleSize

32

Minimum number of connections to each replica node of each shard. If readMode is set to MASTER, the value of this parameter is invalid.

slaveConnectionPoolSize

64

Maximum number of connections to each replica node of each shard. If readMode is set to MASTER, the value of this parameter is invalid.

subscriptionMode

SLAVE

Subscription mode. By default, only replica nodes handle subscription. The value can be SLAVE or MASTER (recommended).

subscriptionConnectionMinimumIdleSize

1

Minimum number of connections to the target node for pub/sub.

subscriptionConnectionPoolSize

50

Maximum number of connections to the target node for pub/sub.

subcriptionPerConnection

5

Maximum number of subscriptions on each subscription connection.

connectionTimeout

10000

Connection timeout interval, in milliseconds.

idleConnectionTimeout

10000

Maximum time (in milliseconds) for reclaiming idle connections.

pingConnectionInterval

30000

Heartbeat for detecting available connections, in milliseconds. Recommended: 3000 ms.

timeout

3000

Timeout interval for waiting for a response, in milliseconds.

retryAttempts

3

Maximum number of retries upon send failures.

retryInterval

1500

Retry interval, in milliseconds. Recommended: 200 ms.

clientName

null

Client name.

Table 4 ClusterServersConfig parameters (Redis Cluster)

Parameter

Default Value

Description

nodeAddress

-

Connection addresses of cluster nodes. Each address uses the redis://ip:port format. Use commas (,) to separate connection addresses of different nodes.

password

null

Password for logging in to the cluster.

scanInterval

1000

Interval for periodically checking the cluster node status, in milliseconds.

readMode

SLAVE

Read mode. By default, read traffic is distributed to replica nodes. The value can be MASTER (recommended), SLAVE, or MASTER_SLAVE. Other values may cause access failures in failover scenarios.

loadBalancer

RoundRobinLoadBalancer

Load balancing algorithm. This parameter is valid only when readMode is set to SLAVE or MASTER_SLAVE. Read traffic is distributed evenly.

masterConnectionMinimumIdleSize

32

Minimum number of connections to the master node of each shard.

masterConnectionPoolSize

64

Maximum number of connections to the master node of each shard.

slaveConnectionMinimumIdleSize

32

Minimum number of connections to each replica node of each shard. If readMode is set to MASTER, the value of this parameter is invalid.

slaveConnectionPoolSize

64

Maximum number of connections to each replica node of each shard. If readMode is set to MASTER, the value of this parameter is invalid.

subscriptionMode

SLAVE

Subscription mode. By default, only replica nodes handle subscription. The value can be SLAVE or MASTER (recommended).

subscriptionConnectionMinimumIdleSize

1

Minimum number of connections to the target node for pub/sub.

subscriptionConnectionPoolSize

50

Maximum number of connections to the target node for pub/sub.

subcriptionPerConnection

5

Maximum number of subscriptions on each subscription connection.

connectionTimeout

10000

Connection timeout interval, in milliseconds.

idleConnectionTimeout

10000

Maximum time (in milliseconds) for reclaiming idle connections.

pingConnectionInterval

30000

Heartbeat for detecting available connections, in milliseconds. Recommended: 3000.

timeout

3000

Timeout interval for waiting for a response, in milliseconds.

retryAttempts

3

Maximum number of retries upon send failures.

retryInterval

1500

Retry interval, in milliseconds. Recommended: 200.

clientName

null

Client name.

Suggestion for Configuring DCS Instances

  • readMode

    MASTER is the recommended value, that is, the master node bears all read and write traffic. This is to avoid data inconsistency caused by master/replica synchronization latency. If the value is SLAVE, all read requests will trigger errors when replicas are faulty. If the value is MASTER_SLAVE, some read requests will trigger errors. Read errors last for the period specified by failedSlaveCheckInterval (180s by default) until the faulty nodes are removed from the available node list.

    If read traffic and write traffic need to be separated, you can use read/write splitting DCS instances. Proxy nodes are deployed in the middle to distribute read and write traffic. When a replica node is faulty, traffic is automatically switched to the master node. The switchover does not interrupt service applications, and the fault detection time window is far shorter than Redisson's window.

  • subscriptionMode

    Similar to readMode, MASTER is the recommended value.

  • Connection pool configuration

    The following calculation is applicable only to common service scenarios. You can customize it based on your service requirements.

    There is no standard connection pool size. You can configure one based on your service traffic. The following formulas are for reference:

    • Minimum number of connections = (QPS of a single node accessing Redis)/(1000 ms/Average time spent on a single command)
    • Maximum number of connections = (QPS of a single node accessing Redis)/(1000 ms/Average time spent on a single command) x 150%

    For example, if the QPS of a service application is about 10,000, each request needs to access Redis 10 times (that is, 100,000 accesses to Redis every second), and the service application has 10 hosts, the calculation is as follows:

    QPS of a single node accessing Redis = 100,000/10 = 10,000

    Average time spent on a single command = 20 ms (Redis takes 5 ms to 10 ms to process a single command under normal conditions. If network jitter occurs, it takes 15 ms to 20 ms.)

    Minimum number of connections = 10,000/(1000 ms/20 ms) = 200

    Maximum number of connections = 10,000/(1000 ms/20 ms) x 150% = 300

  • Retry configuration

    Redisson supports retries. You can set the following parameters based on service requirements. Generally, configure three retries, and set the retry interval to about 200 ms.

    • retryAttempts: number of retry times
    • retryInterval: retry interval

In Redisson, some APIs are implemented through LUA, and the performance is low. You are advised to use Jedis instead of Redisson.