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

Question

How to enable distributed/clustered cache when using Redis with spring-boot cache.
Especially when using Redis through spring-boot-starter-data-redis

Answer 1

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.