Spring Cache with Redis - How to gracefully handle or even skip Caching in case of Connection Failure to Redis - spring-cache

Question

I've enabled Caching in my Spring app and I use Redis to serve the purpose.
However, whenever a connection failure occurs, the app stops working whereas I think it had better
skip the Caching and go on with normal execution flow.
So, does anyone have any idea on how to gracefully do it in Spring ?
Here is the exception I got.
Caused by: org.springframework.data.redis.RedisConnectionFailureException: Cannot get Jedis connection; nested exception is redis.clients.jedis.exceptions.JedisConnectionException: Could not get a resource from the pool

Answer 1

As from Spring Framework 4.1, there is a CacheErrorHandler that you can implement to handle such exceptions. Refer to the javadoc for more details.
You can register it by having your #Configuration class extends CachingConfigurerSupport (see errorHandler()).

Answer 2

You can use CacheErrorHandler as suggested by Stephane Nicoll. But you should make sure to make
RedisCacheManager transactionAware to false in your Redis Cache Config(to make sure the transaction is committed early when executing the caching part and the error is caught by CacheErrorHandler and don't wait until the end of the execution which skips CacheErrorHandler part). The function to set transactionAware to false looks like this:
#Bean
public RedisCacheManager redisCacheManager(LettuceConnectionFactory lettuceConnectionFactory) {
JdkSerializationRedisSerializer redisSerializer = new JdkSerializationRedisSerializer(getClass().getClassLoader());
RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig()
.entryTtl(Duration.ofHours(redisDataTTL))
.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer));
redisCacheConfiguration.usePrefix();
RedisCacheManager redisCacheManager = RedisCacheManager.RedisCacheManagerBuilder.fromConnectionFactory(lettuceConnectionFactory)
.cacheDefaults(redisCacheConfiguration)
.build();
redisCacheManager.setTransactionAware(false);
return redisCacheManager;
}

Answer 3

Similar to what Stephane has mentioned, I have done in by consuming the error in try catch block. Adding a fall back mechanism where if Redis is not up or may be the data is not present then I fetch the data from DB.(Later if I find one then I add the same data in Redis,if it is up to maintain consistency.)