Redis缓存指标在SpringBoot版本2.4.2中不起作用

Question

我们正试图将我们的redis缓存指标暴露给Prometheus。下面是我们所做的工作。

我们有一个CachingConfig类，如下所示：

@Configuration
@EnableCaching
public class CachingConfig {

  private final Duration cacheEntryTtl;

  public CachingConfig(
      @Value("${spring.cache.redis.entryTtl}")
      final Duration cacheEntryTtl
  ) {
    this.cacheEntryTtl = cacheEntryTtl;
  }

  @Bean
  public CacheManager cacheManager(final RedisConnectionFactory redisConnectionFactory) {
    final Map<String, RedisCacheConfiguration> cacheConfigurations = new HashMap<>();
    cacheConfigurations.put("cacheA",cacheConfiguration(cacheEntryTtl));
    cacheConfigurations.put("cacheB",cacheConfiguration(cacheEntryTtl));

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

然后我们在我们的类中使用Redis缓存，如下所示。

public class BusinessService {
    public static final String CACHE_A_NAME = "cacheA"
    private final BusinessServiceClient businessServiceClient;
    private final CacheManager cacheManager;
    private final CacheMetricsRegistrar cacheMetricsRegistrar;

    @PostConstruct
    public void postConstruct() {
        final Cache cache = cacheManager.getCache(CACHE_A_NAME);
        cacheMetricsRegistrar.bindCacheToRegistry(cache);
    }

    @Cacheable(cacheNames = CACHE_A_NAME)
    public Set<String> getOwnersOfProviderAccount(String para1, String para2) {
        return businessServiceClient.getResonponse(para1, para2);
    }
}

根据this的说法，我还在我们的application.properties文件中添加了以下行。

spring.cache.type=redis
spring.cache.redis.enable-statistics=true

因此，理论上，Redis缓存指标应该能够工作，但是当我从以下URL检查我们的缓存指标时。

GET .../actuator/metrics/cache.gets?tag=name:cacheA

响应总是像下面这样，计数总是零，统计似乎不起作用，但我们的Redis缓存工作。

{
   "name":"cache.gets",
   "description":"The number of pending requests",
   "baseUnit":null,
   "measurements":[
      {
         "statistic":"COUNT",
         "value":0.0
      }
   ],
   "availableTags":[
      {
         "tag":"result",
         "values":[
            "hit",
            "pending",
            "miss"
         ]
      },
      {
         "tag":"cache",
         "values":[
            "cacheA"
         ]
      },
      {
         "tag":"application",
         "values":[
            "business-service"
         ]
      },
      {
         "tag":"cacheManager",
         "values":[
            "cacheManager"
         ]
      }
   ]
}

如果我们检查来自/management/prometheus的指标，这是我们得到的结果，所有的值都是零。

# HELP cache_gets_total the number of times cache lookup methods have returned an uncached (newly loaded) value, or null
# TYPE cache_gets_total counter
cache_gets_total{application="business-service",cache="cacheA",cacheManager="cacheManager",name="cacheA",result="miss",} 0.0
cache_gets_total{application="business-service",cache="cacheA",cacheManager="cacheManager",name="cacheA",result="pending",} 0.0
cache_gets_total{application="business-service",cache="cacheA",cacheManager="cacheManager",name="cacheA",result="hit",} 0.0

在配置Redis缓存指标时，我是否遗漏了什么？谢谢，任何有建设性的建议都将不胜感激。

Answer 1

您将自己创建RedisCacheManager，因此缓存管理器自动配置已停止。因此，spring.cache.type=redis是不必要的，更重要的是，spring.cache.redis.enable-statistics=true不会有任何影响。

要在RedisCacheManager上启用统计信息，请在cacheManager @Bean方法中调用构建器上的enableStatistics()方法。