Add MetricRegistries metricsPrefixedBy and metricsMatching (#30)

palantir · Sep 29, 2017 · 7fb2132 · 7fb2132
1 parent ba44bd3
commit 7fb2132
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Showing 2 changed files with 68 additions and 9 deletions.
diff --git a/tritium-metrics/src/main/java/com/palantir/tritium/metrics/MetricRegistries.java b/tritium-metrics/src/main/java/com/palantir/tritium/metrics/MetricRegistries.java
@@ -20,6 +20,7 @@
 
 import com.codahale.metrics.Gauge;
 import com.codahale.metrics.Metric;
+import com.codahale.metrics.MetricFilter;
 import com.codahale.metrics.MetricRegistry;
 import com.codahale.metrics.Reservoir;
 import com.google.common.annotations.VisibleForTesting;
@@ -31,6 +32,8 @@
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.SortedMap;
+import java.util.TreeMap;
 import javax.annotation.concurrent.GuardedBy;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -119,6 +122,34 @@ static <T extends Metric> T getOrAdd(MetricRegistry metrics, String name, Metric
         throw new IllegalArgumentException(name + " is already used for a different type of metric for " + metric);
     }
 
+    /**
+     * Creates a {@link MetricFilter} predicate to match metrics with names starting with the specified prefix.
+     *
+     * @param prefix metric name prefix
+     * @return metric filter
+     */
+    public static MetricFilter metricsPrefixedBy(final String prefix) {
+        checkNotNull(prefix, "prefix");
+        return (name, metric) -> name.startsWith(prefix);
+    }
+
+    /**
+     * Returns a sorted map of metrics from the specified registry matching the specified filter.
+     *
+     * @param metrics metric registry
+     * @param filter metric filter predicate
+     * @return sorted map of metrics
+     */
+    public static SortedMap<String, Metric> metricsMatching(MetricRegistry metrics, MetricFilter filter) {
+        SortedMap<String, Metric> matchingMetrics = new TreeMap<>();
+        metrics.getMetrics().forEach((key, value) -> {
+            if (filter.matches(key, value)) {
+                matchingMetrics.put(key, value);
+            }
+        });
+        return matchingMetrics;
+    }
+
     /**
      * Register specified cache with the given metric registry.
      *

diff --git a/tritium-metrics/src/test/java/com/palantir/tritium/metrics/MetricRegistriesTest.java b/tritium-metrics/src/test/java/com/palantir/tritium/metrics/MetricRegistriesTest.java
@@ -33,6 +33,7 @@
 import com.google.common.cache.LoadingCache;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
+import java.util.SortedMap;
 import java.util.concurrent.TimeUnit;
 import org.junit.After;
 import org.junit.Test;
@@ -90,7 +91,7 @@ public String load(Integer key) throws Exception {
                 });
         MetricRegistries.registerCache(metrics, cache, "test");
 
-        assertThat(metrics.getGauges(metricsPrefixedBy("test")).keySet()).containsExactly(
+        assertThat(metrics.getGauges(MetricRegistries.metricsPrefixedBy("test")).keySet()).containsExactly(
                 "test.cache.estimated.size",
                 "test.cache.eviction.count",
                 "test.cache.hit.count",
@@ -145,7 +146,7 @@ public String load(Integer key) throws Exception {
 
         MetricRegistries.registerCache(metrics, cache, "test");
 
-        assertThat(metrics.getGauges(metricsPrefixedBy("test")).keySet()).containsExactly(
+        assertThat(metrics.getGauges(MetricRegistries.metricsPrefixedBy("test")).keySet()).containsExactly(
                 "test.cache.estimated.size",
                 "test.cache.eviction.count",
                 "test.cache.hit.count",
@@ -220,13 +221,40 @@ public void testInaccessibleConstructor() {
         }
     }
 
-    private static MetricFilter metricsPrefixedBy(final String prefix) {
-        return new MetricFilter() {
-            @Override
-            public boolean matches(String name, Metric metric) {
-                return name.startsWith(prefix);
-            }
-        };
+    @Test
+    public void testMetricsPrefixedBy() {
+        MetricFilter metricFilter = MetricRegistries.metricsPrefixedBy("test");
+
+        Metric metric = mock(Metric.class);
+        assertThat(metricFilter.matches("test", metric)).isTrue();
+        assertThat(metricFilter.matches("test", null)).isTrue();
+        assertThat(metricFilter.matches("test.foo", metric)).isTrue();
+        assertThat(metricFilter.matches("testing", metric)).isTrue();
+        assertThat(metricFilter.matches("bar", metric)).isFalse();
+        assertThat(metricFilter.matches("bar", null)).isFalse();
+    }
+
+    @Test(expected = NullPointerException.class)
+    public void testNullPrefixMetricsPrefixedBy() {
+        assertThat(MetricRegistries.metricsPrefixedBy(null)).isNotNull();
+    }
+
+    @Test
+    public void testMetricsMatching() {
+        MetricFilter palantirFilter = (name, metric) -> name.startsWith("test");
+
+        metrics.counter("test.a");
+        metrics.timer("test.b");
+        metrics.counter("non.matching");
+
+        SortedMap<String, Metric> metricsMatching = MetricRegistries.metricsMatching(metrics, palantirFilter);
+        assertThat(metricsMatching.size()).isEqualTo(2);
+        assertThat(metricsMatching.keySet())
+                .containsAllOf("test.a", "test.b")
+                .inOrder();
+        assertThat(metricsMatching.values())
+                .containsExactly(metrics.counter("test.a"), metrics.timer("test.b"))
+                .inOrder();
     }
 
     private static void report(MetricRegistry metrics) {