Caffeine cache_puts_total counter is always zero

[KazzmanK]

Hi!

Please take a look into issue. Total put counter is constantly zero, other counters are alive.

prometheus-metrics-instrumentation-caffeine 1.3.8
caffeine 3.2.0

[zeitlinger]

Please include steps to reproduce and the metric name that you'd expect.

[KazzmanK]

Hi!
Thank you for response

I have a Boot 3.5 project with a configuration class

@Slf4j
@Configuration
public class CaffeineConfig {

    @Value("${lsl.CACHE_DURATION:15}")
    private int cacheDuration;

    @Value("${lsl.MAX_CACHE_SIZE:1000}")
    private int maxCacheSize;

    @Bean
    public Cache<String, Tpe> tCache() {
        return Caffeine.newBuilder()
                .recordStats()
                .expireAfterWrite(cacheDuration, TimeUnit.SECONDS)
                .initialCapacity(100)
                .maximumSize(maxCacheSize)
                .build();
    }

    @Bean
    public CaffeineCacheMetrics<String, Tpe, Cache<String, Tpe>> caffeineCacheMetrics(
            Cache<String, Tpe> tCache) {
        return new CaffeineCacheMetrics<>(tCache, "tCache", null);
    }
}

after, I`m autowire beans in service

    @Autowired
    Cache<String, Tpe> tCache;

.....

   Tpe t = tCache.getIfPresent(key);
   tCache.put(key, t);

but after a while stats are
/actuator/prometheus

# HELP cache_eviction_weight_total The sum of weights of evicted entries. This total does not include manual invalidations.
# TYPE cache_eviction_weight_total counter
cache_eviction_weight_total{cache="tCache"} 19327.0
# HELP cache_evictions_total The number of times the cache was evicted.
# TYPE cache_evictions_total counter
cache_evictions_total{cache="tCache"} 19327.0
# HELP cache_gets_total The number of times cache lookup methods have returned a cached (hit) or uncached (newly loaded or null) value (miss).
# TYPE cache_gets_total counter
cache_gets_total{cache="tCache",result="hit"} 12655.0
cache_gets_total{cache="tCache",result="miss"} 19329.0
# HELP cache_puts_total The number of entries added to the cache
# TYPE cache_puts_total counter
cache_puts_total{cache="tCache"} 0.0
# HELP cache_size The number of entries in this cache. This may be an approximation, depending on the type of cache.
# TYPE cache_size gauge
cache_size{cache="tCache"} 2.0

as you can see cache_puts_total is zero

[zeitlinger]

heads up: it will take some time until I can look into the issue - help is very welcome 😄

[pheyken]

Hey,

CaffeineCacheMetrics is not the collector in prometheus-metrics-instrumentation-caffeine, but coming from micrometer.

The one provided by prometheus-metrics-instrumentation-caffeine is CacheMetricsCollector. The counters are also prefixed with caffeine_

[jaydeluca]

Hey @KazzmanK, as @pheyken points out, it doesn't look like you are using prometheus for your caffeine metrics, so you might want to open an issue with micrometer instead.