ENG 5066: GuavaCacheMetric Support (#32)

* ENG-5066: GuavaCache Metrics Support

* ENG 5066: GuavaCache Metric Support

* ENG-5066, GuavaCache Metric Support (code formatting fixed)

* ENG-5066: GuavaCacheMetric Support, Fixed test-cases

* ENG 5066: GuavaCacheMetric; Added test for cache size, Better efficient meter access

* ENG 5066: GuavaCacheMetric Support, formatting issues

* ENG 5066: GuavaCacheMetrics, Made comments more verbose

* ENG 5066: GuavaCacheMetrics, Made comments more verbose

Co-authored-by: Apoorv Jain <[email protected]>

Author: Apoorv Jain

platform-metrics/build.gradle.kts

@@ -23,6 +23,7 @@ dependencies {
   implementation("io.prometheus:simpleclient_servlet:0.6.0")
   implementation("io.prometheus:simpleclient_pushgateway:0.9.0")
   implementation("org.eclipse.jetty:jetty-servlet:9.4.42.v20210604")
+  implementation ("com.google.guava:guava:30.1.1-jre")
 
   testImplementation("org.junit.jupiter:junit-jupiter:5.7.1")
   testImplementation("org.mockito:mockito-core:3.8.0")

platform-metrics/src/main/java/org/hypertrace/core/serviceframework/metrics/PlatformMetricsRegistry.java

@@ -8,6 +8,7 @@
 import com.codahale.metrics.jvm.JvmAttributeGaugeSet;
 import com.codahale.metrics.jvm.MemoryUsageGaugeSet;
 import com.codahale.metrics.jvm.ThreadStatesGaugeSet;
+import com.google.common.cache.Cache;
 import com.typesafe.config.Config;
 import io.github.mweirauch.micrometer.jvm.extras.ProcessMemoryMetrics;
 import io.github.mweirauch.micrometer.jvm.extras.ProcessThreadMetrics;
@@ -19,6 +20,7 @@
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.Tag;
 import io.micrometer.core.instrument.Timer;
+import io.micrometer.core.instrument.binder.cache.GuavaCacheMetrics;
 import io.micrometer.core.instrument.binder.jvm.ClassLoaderMetrics;
 import io.micrometer.core.instrument.binder.jvm.ExecutorServiceMetrics;
 import io.micrometer.core.instrument.binder.jvm.JvmGcMetrics;
@@ -375,9 +377,17 @@ public static DistributionSummary registerDistributionSummary(String name,
   }
 
   /**
-   * Registers metrics for the given executor service with the service's metric registry and
-   * reports them periodically to the configured reporters. Apart from the given tags, the
-   * reporting service's default tags also will be reported with the metrics.
+   * Registers metrics for GuavaCaches using micrometer's GuavaCacheMetrics under the given
+   * cacheName for the given guavaCache
+   */
+  public static <K, V> void registerCache(String cacheName, Cache<K, V> guavaCache) {
+    GuavaCacheMetrics.monitor(METER_REGISTRY, guavaCache, cacheName);
+  }
+
+  /**
+   * Registers metrics for the given executor service with the service's metric registry and reports
+   * them periodically to the configured reporters. Apart from the given tags, the reporting
+   * service's default tags also will be reported with the metrics.
    *
    * See https://micrometer.io/docs/ref/jvm for more details on the metrics.
    */

platform-metrics/src/test/java/org/hypertrace/core/serviceframework/metrics/PlatformMetricsRegistryTest.java

@@ -3,6 +3,8 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
 import com.typesafe.config.Config;
 import com.typesafe.config.ConfigFactory;
 import io.micrometer.core.instrument.Counter;
@@ -13,6 +15,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.Callable;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.stream.Collectors;
@@ -151,9 +154,66 @@ public void testDistributionSummary() {
     assertEquals(1, distribution.count());
     assertEquals(100, distribution.totalAmount());
     assertTrue(
-        Arrays.stream(distribution.takeSnapshot().percentileValues()).map(m -> m.percentile())
-            .collect(
-                Collectors.toList()).containsAll(List.of(0.5, 0.95, 0.99)));
+        Arrays.stream(distribution.takeSnapshot().percentileValues())
+            .map(m -> m.percentile())
+            .collect(Collectors.toList())
+            .containsAll(List.of(0.5, 0.95, 0.99)));
+  }
+
+  @Test
+  public void testCache() throws Exception {
+    initializeCustomRegistry(List.of("testing"));
+    Cache<String, Integer> cache = CacheBuilder.newBuilder().maximumSize(10).recordStats().build();
+
+    PlatformMetricsRegistry.registerCache("my.cache", cache);
+    Callable<Integer> loader =
+        new Callable<Integer>() {
+          @Override
+          public Integer call() throws Exception {
+            return -1;
+          }
+        };
+
+    // Doing some cache activity
+    cache.put("One", 1);
+    cache.put("Two", 2);
+    cache.get("One", loader); // hit
+    cache.get("Two", loader); // hit
+    cache.get("Two", loader); // hit
+    cache.get("Three", loader); // miss hence loaded from loader
+    cache.get("Failed", loader); // miss hence loaded from loader
+    /*
+    * Cache = {One,Two, Three, Failed}
+    * Cache Hit is basically the number of times cache.get returned an entry which was present in the cache, hence hit = 3
+    * Cache Miss is basically the number of times cache.get returned an entry not present in the cache (hence loaded from loader), hence miss = 2
+    * The way cache.get works is that if there is a cache miss then the entry is loaded from the loader and included in the cache,
+    hence the cache size due to the above activity would be 2 (already put One,Two) + 2 (cache miss on Three, Failed) = 4
+
+    Expected hit count = 3.0, miss count = 2.0, cache size = 4
+     */
+
+    // Checking Cache Stats from registry
+    double hits = 0, misses = 0,size = 0;
+    hits = PlatformMetricsRegistry.getMeterRegistry().get("cache.gets").tag("result","hit").meter().measure().iterator().next().getValue();
+    misses = PlatformMetricsRegistry.getMeterRegistry().get("cache.gets").tag("result","miss").meter().measure().iterator().next().getValue();
+    size = PlatformMetricsRegistry.getMeterRegistry().get("cache.size").meter().measure().iterator().next().getValue();
+
+    assertEquals(3.0, hits);
+    assertEquals(2.0, misses);
+    assertEquals(4.0,size);
+
+    // Doing some more cache activity
+    cache.get("NotPresent", loader); // miss hence loaded from loader
+
+    // Cache = {One,Two,Three,Failed,NotPresent}
+    // expected hit=3.0, miss=3.0, size=5.0
+    hits = PlatformMetricsRegistry.getMeterRegistry().get("cache.gets").tag("result","hit").meter().measure().iterator().next().getValue();
+    misses = PlatformMetricsRegistry.getMeterRegistry().get("cache.gets").tag("result","miss").meter().measure().iterator().next().getValue();
+    size = PlatformMetricsRegistry.getMeterRegistry().get("cache.size").meter().measure().iterator().next().getValue();
+
+    assertEquals(3.0, hits);
+    assertEquals(3.0, misses);
+    assertEquals(5.0,size);
   }
 
   @Test