How to enable distributed/clustered cache when using redis with spring data cache

Enable caching in the spring boot app is very simple. You would need to just follow three steps.

• Define cache configuration
• Add EnableCaching to any configuration class
• Provide a CacheManager bean

For Redis, we've RedisCacheManager that can be configured and created.

Cache Configuration

@Configuration
@Getter
@Setter
@ConfigurationProperties(prefix = "cache")
public class CacheConfigurationProperties {
 // Redis host name
  private String redisHost;
 // Redis port
  private int redisPort;
  // Default TTL
  private long timeoutSeconds;
  // TTL per cache, add enties for each cache
  private Map<String, Long> cacheTtls;
}

Set their values via properties or yaml file like

cache.redisHost=localhost
cache.redisPort=6379
cache.timeoutSeconds=1000
cache.cacheTtls.cach1=100
cache.cacheTtls.cach2=200

Once you have created configuration, you can create cache config for RedisCacheManger by builder.

@Configuration
@EnableCaching
public class CacheConfig {
  private static RedisCacheConfiguration createCacheConfiguration(long timeoutInSeconds) {
    return RedisCacheConfiguration.defaultCacheConfig()
        .entryTtl(Duration.ofSeconds(timeoutInSeconds));
  }

  @Bean
  public LettuceConnectionFactory redisConnectionFactory(CacheConfigurationProperties properties) {
    RedisStandaloneConfiguration redisStandaloneConfiguration = new RedisStandaloneConfiguration();
    redisStandaloneConfiguration.setHostName(properties.getRedisHost());
    redisStandaloneConfiguration.setPort(properties.getRedisPort());
    return new LettuceConnectionFactory(redisStandaloneConfiguration);
  }

  @Bean
  public RedisCacheConfiguration cacheConfiguration(CacheConfigurationProperties properties) {
    return createCacheConfiguration(properties.getTimeoutSeconds());
  }

  @Bean
  public CacheManager cacheManager(
      RedisConnectionFactory redisConnectionFactory, CacheConfigurationProperties properties) {
    Map<String, RedisCacheConfiguration> cacheConfigurations = new HashMap<>();

    for (Entry<String, Long> cacheNameAndTimeout : properties.getCacheTtls().entrySet()) {
      cacheConfigurations.put(
          cacheNameAndTimeout.getKey(), createCacheConfiguration(cacheNameAndTimeout.getValue()));
    }

    return RedisCacheManager.builder(redisConnectionFactory)
        .cacheDefaults(cacheConfiguration(properties))
        .withInitialCacheConfigurations(cacheConfigurations)
        .build();
  }
}

If you're using Redis cluster than update cache properties as per that. In this some beans would become primary if you want cache specific bean than make these methods private.