Polish "Stop MetricsEndpoint from summing up same metrics"

See gh-14497

Author: philwebb

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/MetricsEndpoint.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.actuate.metrics;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -115,19 +116,17 @@ private Tag parseTag(String tag) {
 	private Collection<Meter> findFirstMatchingMeters(MeterRegistry registry, String name,
 			Iterable<Tag> tags) {
 		if (registry instanceof CompositeMeterRegistry) {
-			return ((CompositeMeterRegistry) registry).getRegistries().stream()
-					.map((r) -> findFirstMatchingMeters(r, name, tags))
-					.filter((match) -> !match.isEmpty()).findFirst()
-					.orElse(Collections.emptyList());
-
-		}
-		else {
-			Collection<Meter> metersFound = registry.find(name).tags(tags).meters();
-			if (!metersFound.isEmpty()) {
-				return metersFound;
-			}
+			return findFirstMatchingMeters((CompositeMeterRegistry) registry, name, tags);
 		}
-		return Collections.emptyList();
+		return registry.find(name).tags(tags).meters();
+	}
+
+	private Collection<Meter> findFirstMatchingMeters(CompositeMeterRegistry composite,
+			String name, Iterable<Tag> tags) {
+		return composite.getRegistries().stream()
+				.map((registry) -> findFirstMatchingMeters(registry, name, tags))
+				.filter((matching) -> !matching.isEmpty()).findFirst()
+				.orElse(Collections.emptyList());
 	}
 
 	private Map<Statistic, Double> getSamples(Collection<Meter> meters) {

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/MetricsEndpointTests.java

@@ -98,30 +98,21 @@ public void metricValuesAreTheSumOfAllTimeSeriesMatchingTags() {
 	@Test
 	public void findFirstMatchingMetersFromNestedRegistries() {
 		CompositeMeterRegistry composite = new CompositeMeterRegistry();
-		SimpleMeterRegistry reg1 = new SimpleMeterRegistry();
-		CompositeMeterRegistry reg2 = new CompositeMeterRegistry();
-		SimpleMeterRegistry reg3 = new SimpleMeterRegistry();
-
-		// 1st level nesting
-		composite.add(reg1);
-
-		// 2st level nesting
-		reg2.add(reg3);
-		composite.add(reg2);
-
-		// 2nd level registry has metrics
-		reg3.counter("cache", "result", "hit", "host", "1").increment(2);
-		reg3.counter("cache", "result", "miss", "host", "1").increment(2);
-		reg3.counter("cache", "result", "hit", "host", "2").increment(2);
-
+		SimpleMeterRegistry firstLevel0 = new SimpleMeterRegistry();
+		CompositeMeterRegistry firstLevel1 = new CompositeMeterRegistry();
+		SimpleMeterRegistry secondLevel = new SimpleMeterRegistry();
+		composite.add(firstLevel0);
+		composite.add(firstLevel1);
+		firstLevel1.add(secondLevel);
+		secondLevel.counter("cache", "result", "hit", "host", "1").increment(2);
+		secondLevel.counter("cache", "result", "miss", "host", "1").increment(2);
+		secondLevel.counter("cache", "result", "hit", "host", "2").increment(2);
 		MetricsEndpoint endpoint = new MetricsEndpoint(composite);
-
 		MetricsEndpoint.MetricResponse response = endpoint.metric("cache",
 				Collections.emptyList());
 		assertThat(response.getName()).isEqualTo("cache");
 		assertThat(availableTagKeys(response)).containsExactly("result", "host");
 		assertThat(getCount(response)).hasValue(6.0);
-
 		response = endpoint.metric("cache", Collections.singletonList("result:hit"));
 		assertThat(availableTagKeys(response)).containsExactly("host");
 		assertThat(getCount(response)).hasValue(4.0);
@@ -130,15 +121,11 @@ public void findFirstMatchingMetersFromNestedRegistries() {
 	@Test
 	public void matchingMeterNotFoundInNestedRegistries() {
 		CompositeMeterRegistry composite = new CompositeMeterRegistry();
-		CompositeMeterRegistry reg2 = new CompositeMeterRegistry();
-		SimpleMeterRegistry reg3 = new SimpleMeterRegistry();
-
-		// nested registries
-		reg2.add(reg3);
-		composite.add(reg2);
-
+		CompositeMeterRegistry firstLevel = new CompositeMeterRegistry();
+		SimpleMeterRegistry secondLevel = new SimpleMeterRegistry();
+		composite.add(firstLevel);
+		firstLevel.add(secondLevel);
 		MetricsEndpoint endpoint = new MetricsEndpoint(composite);
-
 		MetricsEndpoint.MetricResponse response = endpoint.metric("invalid.metric.name",
 				Collections.emptyList());
 		assertThat(response).isNull();