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Add caffeine metric collector (#198)
Add caffeine metric collector
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‎README.md‎

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@@ -274,6 +274,28 @@ To register the log4j2 collector at root level:
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</Configuration>
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```
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#### Caches
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To register the Guava cache collector, be certain to add `recordStats()` when building
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the cache and adding it to the registered collector.
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```java
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CacheMetricsCollector cacheMetrics = new CacheMetricsCollector().register();
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Cache<String, String> cache = CacheBuilder.newBuilder().recordStats().build();
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cacheMetrics.addCache("myCacheLabel", cache);
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```
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The Caffeine equivalent is nearly identical. Again, be certain to call `recordStats()`
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when building the cache so that metrics are collected.
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```java
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CacheMetricsCollector cacheMetrics = new CacheMetricsCollector().register();
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Cache<String, String> cache = Caffeine.newBuilder().recordStats().build();
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cacheMetrics.addCache("myCacheLabel", cache);
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```
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#### Hibernate
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There is a collector for Hibernate which allows to collect metrics from one or more

‎pom.xml‎

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<modules>
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<module>simpleclient</module>
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<module>simpleclient_common</module>
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<module>simpleclient_caffeine</module>
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<module>simpleclient_dropwizard</module>
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<module>simpleclient_graphite_bridge</module>
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<module>simpleclient_hibernate</module>

‎simpleclient_caffeine/pom.xml‎

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<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<parent>
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<groupId>io.prometheus</groupId>
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<artifactId>parent</artifactId>
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<version>0.0.21-SNAPSHOT</version>
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</parent>
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<groupId>io.prometheus</groupId>
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<artifactId>simpleclient_caffeine</artifactId>
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<packaging>bundle</packaging>
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<name>Prometheus Java Simpleclient Caffeine</name>
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<description>
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Metrics collector for caffeine based caches
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</description>
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<licenses>
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<license>
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<name>The Apache Software License, Version 2.0</name>
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<url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
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<distribution>repo</distribution>
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</license>
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</licenses>
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<developers>
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<developer>
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<id>checketts</id>
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<name>Clint Checketts</name>
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<email>[email protected]</email>
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</developer>
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</developers>
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<dependencies>
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<dependency>
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<groupId>io.prometheus</groupId>
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<artifactId>simpleclient</artifactId>
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<version>0.0.21-SNAPSHOT</version>
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</dependency>
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<dependency>
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<groupId>com.github.ben-manes.caffeine</groupId>
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<artifactId>caffeine</artifactId>
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<version>2.3.0</version>
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</dependency>
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<dependency>
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<groupId>junit</groupId>
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<artifactId>junit</artifactId>
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<version>4.11</version>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>org.mockito</groupId>
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<artifactId>mockito-core</artifactId>
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<version>1.9.5</version>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>org.assertj</groupId>
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<artifactId>assertj-core</artifactId>
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<version>2.6.0</version>
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<scope>test</scope>
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</dependency>
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</dependencies>
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</project>

‎simpleclient_caffeine/src/main/java/io/prometheus/client/cache/caffeine/CacheMetricsCollector.java‎

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package io.prometheus.client.cache.caffeine;
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import com.github.benmanes.caffeine.cache.AsyncLoadingCache;
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import com.github.benmanes.caffeine.cache.Cache;
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import com.github.benmanes.caffeine.cache.LoadingCache;
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import com.github.benmanes.caffeine.cache.stats.CacheStats;
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import io.prometheus.client.Collector;
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import io.prometheus.client.CounterMetricFamily;
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import io.prometheus.client.GaugeMetricFamily;
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import io.prometheus.client.SummaryMetricFamily;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.List;
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import java.util.Map;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.ConcurrentMap;
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/**
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* Collect metrics from Caffiene's com.github.benmanes.caffeine.cache.Cache.
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* <p>
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* <pre>{@code
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*
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* // Note that `recordStats()` is required to gather non-zero statistics
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* Cache<String, String> cache = Caffeine.newBuilder().recordStats().build();
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* CacheMetricsCollector cacheMetrics = new CacheMetricsCollector().register();
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* cacheMetrics.addCache("mycache", cache);
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*
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* }</pre>
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*
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* Exposed metrics are labeled with the provided cache name.
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*
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* With the example above, sample metric names would be:
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* <pre>
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* caffeine_cache_hit_total{cache="mycache"} 10.0
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* caffeine_cache_miss_total{cache="mycache"} 3.0
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* caffeine_cache_requests_total{cache="mycache"} 13.0
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* caffeine_cache_eviction_total{cache="mycache"} 1.0
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* </pre>
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*
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* Additionally if the cache includes a loader, the following metrics would be provided:
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* <pre>
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* caffeine_cache_load_failure_total{cache="mycache"} 2.0
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* caffeine_cache_loads_total{cache="mycache"} 7.0
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* caffeine_cache_load_duration_seconds_count{cache="mycache"} 7.0
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* caffeine_cache_load_duration_seconds_sum{cache="mycache"} 0.0034
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* </pre>
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*
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*/
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public class CacheMetricsCollector extends Collector {
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protected final ConcurrentMap<String, Cache> children = new ConcurrentHashMap<String, Cache>();
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/**
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* Add or replace the cache with the given name.
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* <p>
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* Any references any previous cache with this name is invalidated.
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*
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* @param cacheName The name of the cache, will be the metrics label value
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* @param cache The cache being monitored
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*/
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public void addCache(String cacheName, Cache cache) {
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children.put(cacheName, cache);
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}
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/**
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* Add or replace the cache with the given name.
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* <p>
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* Any references any previous cache with this name is invalidated.
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*
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* @param cacheName The name of the cache, will be the metrics label value
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* @param cache The cache being monitored
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*/
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public void addCache(String cacheName, AsyncLoadingCache cache) {
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children.put(cacheName, cache.synchronous());
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}
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/**
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* Remove the cache with the given name.
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* <p>
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* Any references to the cache are invalidated.
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*
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* @param cacheName cache to be removed
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*/
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public Cache removeCache(String cacheName) {
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return children.remove(cacheName);
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}
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/**
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* Remove all caches.
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* <p>
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* Any references to all caches are invalidated.
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*/
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public void clear(){
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children.clear();
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}
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@Override
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public List<MetricFamilySamples> collect() {
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List<MetricFamilySamples> mfs = new ArrayList<MetricFamilySamples>();
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List<String> labelNames = Arrays.asList("cache");
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CounterMetricFamily cacheHitTotal = new CounterMetricFamily("caffeine_cache_hit_total",
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"Cache hit totals", labelNames);
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mfs.add(cacheHitTotal);
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CounterMetricFamily cacheMissTotal = new CounterMetricFamily("caffeine_cache_miss_total",
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"Cache miss totals", labelNames);
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mfs.add(cacheMissTotal);
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CounterMetricFamily cacheRequestsTotal = new CounterMetricFamily("caffeine_cache_requests_total",
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"Cache request totals, hits + misses", labelNames);
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mfs.add(cacheRequestsTotal);
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CounterMetricFamily cacheEvictionTotal = new CounterMetricFamily("caffeine_cache_eviction_total",
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"Cache eviction totals, doesn't include manually removed entries", labelNames);
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mfs.add(cacheEvictionTotal);
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GaugeMetricFamily cacheEvictionWeight = new GaugeMetricFamily("caffeine_cache_eviction_weight",
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"Cache eviction weight", labelNames);
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mfs.add(cacheEvictionWeight);
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CounterMetricFamily cacheLoadFailure = new CounterMetricFamily("caffeine_cache_load_failure_total",
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"Cache load failures", labelNames);
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mfs.add(cacheLoadFailure);
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CounterMetricFamily cacheLoadTotal = new CounterMetricFamily("caffeine_cache_loads_total",
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"Cache loads: both success and failures", labelNames);
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mfs.add(cacheLoadTotal);
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SummaryMetricFamily cacheLoadSummary = new SummaryMetricFamily("caffeine_cache_load_duration_seconds",
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"Cache load duration: both success and failures", labelNames);
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mfs.add(cacheLoadSummary);
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for(Map.Entry<String, Cache> c: children.entrySet()) {
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List<String> cacheName = Arrays.asList(c.getKey());
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CacheStats stats = c.getValue().stats();
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try{
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cacheEvictionWeight.addMetric(cacheName, stats.evictionWeight());
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} catch (Exception e) {
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// EvictionWeight metric is unavailable, newer version of Caffeine is needed.
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}
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cacheHitTotal.addMetric(cacheName, stats.hitCount());
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cacheMissTotal.addMetric(cacheName, stats.missCount());
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cacheRequestsTotal.addMetric(cacheName, stats.requestCount());
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cacheEvictionTotal.addMetric(cacheName, stats.evictionCount());
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if(c.getValue() instanceof LoadingCache) {
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cacheLoadFailure.addMetric(cacheName, stats.loadFailureCount());
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cacheLoadTotal.addMetric(cacheName, stats.loadCount());
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cacheLoadSummary.addMetric(cacheName, stats.loadCount(), stats.totalLoadTime() / Collector.NANOSECONDS_PER_SECOND);
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}
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}
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return mfs;
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}
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}

‎simpleclient_caffeine/src/test/java/io/prometheus/client/cache/caffeine/CacheMetricsCollectorTest.java‎

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package io.prometheus.client.cache.caffeine;
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import com.github.benmanes.caffeine.cache.AsyncLoadingCache;
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import com.github.benmanes.caffeine.cache.Cache;
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import com.github.benmanes.caffeine.cache.CacheLoader;
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import com.github.benmanes.caffeine.cache.Caffeine;
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import com.github.benmanes.caffeine.cache.LoadingCache;
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import io.prometheus.client.CollectorRegistry;
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import org.junit.Test;
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import java.util.concurrent.CompletableFuture;
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import java.util.concurrent.Executor;
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import static org.assertj.core.api.Java6Assertions.assertThat;
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import static org.mockito.Matchers.anyString;
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import static org.mockito.Mockito.mock;
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import static org.mockito.Mockito.when;
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public class CacheMetricsCollectorTest {
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@Test
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public void cacheExposesMetricsForHitMissAndEviction() throws Exception {
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Cache<String, String> cache = Caffeine.newBuilder().maximumSize(2).recordStats().executor(new Executor() {
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@Override
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public void execute(Runnable command) {
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// Run cleanup in same thread, to remove async behavior with evictions
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command.run();
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}
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}).build();
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CollectorRegistry registry = new CollectorRegistry();
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CacheMetricsCollector collector = new CacheMetricsCollector().register(registry);
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collector.addCache("users", cache);
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cache.getIfPresent("user1");
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cache.getIfPresent("user1");
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cache.put("user1", "First User");
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cache.getIfPresent("user1");
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// Add to cache to trigger eviction.
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cache.put("user2", "Second User");
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cache.put("user3", "Third User");
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cache.put("user4", "Fourth User");
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assertMetric(registry, "caffeine_cache_hit_total", "users", 1.0);
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assertMetric(registry, "caffeine_cache_miss_total", "users", 2.0);
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assertMetric(registry, "caffeine_cache_requests_total", "users", 3.0);
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assertMetric(registry, "caffeine_cache_eviction_total", "users", 2.0);
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}
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@SuppressWarnings("unchecked")
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@Test
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public void loadingCacheExposesMetricsForLoadsAndExceptions() throws Exception {
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CacheLoader<String, String> loader = mock(CacheLoader.class);
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when(loader.load(anyString()))
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.thenReturn("First User")
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.thenThrow(new RuntimeException("Seconds time fails"))
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.thenReturn("Third User");
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LoadingCache<String, String> cache = Caffeine.newBuilder().recordStats().build(loader);
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CollectorRegistry registry = new CollectorRegistry();
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CacheMetricsCollector collector = new CacheMetricsCollector().register(registry);
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collector.addCache("loadingusers", cache);
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cache.get("user1");
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cache.get("user1");
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try {
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cache.get("user2");
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} catch (Exception e) {
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// ignoring.
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}
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cache.get("user3");
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assertMetric(registry, "caffeine_cache_hit_total", "loadingusers", 1.0);
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assertMetric(registry, "caffeine_cache_miss_total", "loadingusers", 3.0);
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assertMetric(registry, "caffeine_cache_load_failure_total", "loadingusers", 1.0);
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assertMetric(registry, "caffeine_cache_loads_total", "loadingusers", 3.0);
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assertMetric(registry, "caffeine_cache_load_duration_seconds_count", "loadingusers", 3.0);
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assertMetricGreatThan(registry, "caffeine_cache_load_duration_seconds_sum", "loadingusers", 0.0);
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}
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private void assertMetric(CollectorRegistry registry, String name, String cacheName, double value) {
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assertThat(registry.getSampleValue(name, new String[]{"cache"}, new String[]{cacheName})).isEqualTo(value);
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}
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private void assertMetricGreatThan(CollectorRegistry registry, String name, String cacheName, double value) {
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assertThat(registry.getSampleValue(name, new String[]{"cache"}, new String[]{cacheName})).isGreaterThan(value);
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}
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}

‎simpleclient_guava/src/main/java/io/prometheus/client/guava/cache/CacheMetricsCollector.java‎

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import com.google.common.cache.CacheStats;
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import com.google.common.cache.LoadingCache;
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import io.prometheus.client.Collector;
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import io.prometheus.client.Counter;
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import io.prometheus.client.CounterMetricFamily;
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import io.prometheus.client.Gauge;
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import io.prometheus.client.SummaryMetricFamily;
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import java.util.ArrayList;

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