[6.4] fix memory leak in metrics

api/src/main/java/io/smallrye/faulttolerance/api/FaultTolerance.java

@@ -244,7 +244,7 @@ interface Builder<T, R> {
          * <p>
          * The description may be an arbitrary string. Duplicates are permitted.
          * <p>
-         * If no description is set, a random UUID is used.
+         * If no description is set, no metrics are emitted and a random UUID is used for other purposes.
          *
          * @param value a description, must not be {@code null}
          * @return this fault tolerance builder

doc/modules/ROOT/pages/reference/programmatic-api.adoc

@@ -352,7 +352,7 @@ private static final FaultTolerance<String> guarded = FaultTolerance.<String>cre
 It is possible to create multiple `FaultTolerance` objects with the same description.
 In this case, it won't be possbile to distinguish the different `FaultTolerance` objects in metrics; their values will be aggregated.
 
-If no description is provided, a random UUID is used.
+If no description is provided, metrics are not emitted.
 
 == Integration Concerns
 

implementation/core/src/main/java/io/smallrye/faulttolerance/core/apiimpl/FaultToleranceImpl.java

@@ -138,6 +138,7 @@ public static final class BuilderImpl<T, R> implements Builder<T, R> {
         private final Function<FaultTolerance<T>, R> finisher;
 
         private String description;
+        private boolean descriptionSet;
         private BulkheadBuilderImpl<T, R> bulkheadBuilder;
         private CircuitBreakerBuilderImpl<T, R> circuitBreakerBuilder;
         private FallbackBuilderImpl<T, R> fallbackBuilder;
@@ -156,11 +157,13 @@ public BuilderImpl(BuilderEagerDependencies eagerDependencies, Supplier<BuilderL
             this.finisher = finisher;
 
             this.description = UUID.randomUUID().toString();
+            this.descriptionSet = false;
         }
 
         @Override
         public Builder<T, R> withDescription(String value) {
             this.description = Preconditions.checkNotNull(value, "Description must be set");
+            this.descriptionSet = true;
             return this;
         }
 
@@ -324,7 +327,7 @@ private FaultToleranceStrategy<T> buildSyncStrategy(BuilderLazyDependencies lazy
                                 fallbackBuilder.whenPredicate));
             }
 
-            if (lazyDependencies.metricsProvider().isEnabled()) {
+            if (lazyDependencies.metricsProvider().isEnabled() && descriptionSet) {
                 MeteredOperation meteredOperation = buildMeteredOperation();
                 result = new MetricsCollector<>(result, lazyDependencies.metricsProvider().create(meteredOperation),
                         meteredOperation);
@@ -406,7 +409,7 @@ private <V> FaultToleranceStrategy<CompletionStage<V>> buildAsyncStrategy(Builde
                                 fallbackBuilder.whenPredicate));
             }
 
-            if (lazyDependencies.metricsProvider().isEnabled()) {
+            if (lazyDependencies.metricsProvider().isEnabled() && descriptionSet) {
                 MeteredOperation meteredOperation = buildMeteredOperation();
                 result = new CompletionStageMetricsCollector<>(result,
                         lazyDependencies.metricsProvider().create(meteredOperation), meteredOperation);

implementation/standalone/src/test/java/io/smallrye/faulttolerance/standalone/test/StandaloneMetricsTest.java

@@ -12,6 +12,7 @@
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
+import io.micrometer.core.instrument.Counter;
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.Tag;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
@@ -62,7 +63,9 @@ public static void tearDown() throws InterruptedException {
     }
 
     @Test
-    public void test() throws Exception {
+    public void metricsWithDescription() throws Exception {
+        long oldCounters = metrics.getMeters().stream().filter(it -> it instanceof Counter).count();
+
         Callable<String> guarded = FaultTolerance.createCallable(this::action)
                 .withDescription(NAME)
                 .withFallback().handler(this::fallback).done()
@@ -71,6 +74,8 @@ public void test() throws Exception {
 
         assertThat(guarded.call()).isEqualTo("fallback");
 
+        assertThat(metrics.getMeters().stream().filter(it -> it instanceof Counter).count()).isGreaterThan(oldCounters);
+
         assertThat(metrics.counter(MetricsConstants.INVOCATIONS_TOTAL, List.of(
                 Tag.of("method", NAME),
                 Tag.of("result", "valueReturned"),
@@ -87,6 +92,20 @@ public void test() throws Exception {
                 .count()).isEqualTo(1.0);
     }
 
+    @Test
+    public void noMetricsWithoutDescription() throws Exception {
+        long oldCounters = metrics.getMeters().stream().filter(it -> it instanceof Counter).count();
+
+        Callable<String> guarded = FaultTolerance.createCallable(this::action)
+                .withFallback().handler(this::fallback).done()
+                .withRetry().maxRetries(3).done()
+                .build();
+
+        assertThat(guarded.call()).isEqualTo("fallback");
+
+        assertThat(metrics.getMeters().stream().filter(it -> it instanceof Counter).count()).isEqualTo(oldCounters);
+    }
+
     public String action() throws TestException {
         throw new TestException();
     }

testsuite/basic/src/test/java/io/smallrye/faulttolerance/programmatic/CdiMetricsTest.java

@@ -20,7 +20,9 @@ public class CdiMetricsTest {
     private static final String NAME = CdiMetricsTest.class.getName() + " programmatic usage";
 
     @Test
-    public void test(@RegistryType(type = MetricRegistry.Type.BASE) MetricRegistry metrics) throws Exception {
+    public void metricsWithDescription(@RegistryType(type = MetricRegistry.Type.BASE) MetricRegistry metrics) throws Exception {
+        int oldCounters = metrics.getCounters().size();
+
         Callable<String> guarded = FaultTolerance.createCallable(this::action)
                 .withDescription(NAME)
                 .withFallback().handler(this::fallback).done()
@@ -29,6 +31,8 @@ public void test(@RegistryType(type = MetricRegistry.Type.BASE) MetricRegistry m
 
         assertThat(guarded.call()).isEqualTo("fallback");
 
+        assertThat(metrics.getCounters().size()).isGreaterThan(oldCounters);
+
         assertThat(metrics.counter(MetricsConstants.INVOCATIONS_TOTAL,
                 new Tag("method", NAME),
                 new Tag("result", "valueReturned"),
@@ -45,6 +49,21 @@ public void test(@RegistryType(type = MetricRegistry.Type.BASE) MetricRegistry m
                 .getCount()).isEqualTo(1);
     }
 
+    @Test
+    public void noMetricsWithoutDescription(@RegistryType(type = MetricRegistry.Type.BASE) MetricRegistry metrics)
+            throws Exception {
+        int oldCounters = metrics.getCounters().size();
+
+        Callable<String> guarded = FaultTolerance.createCallable(this::action)
+                .withFallback().handler(this::fallback).done()
+                .withRetry().maxRetries(3).done()
+                .build();
+
+        assertThat(guarded.call()).isEqualTo("fallback");
+
+        assertThat(metrics.getCounters().size()).isEqualTo(oldCounters);
+    }
+
     public String action() throws TestException {
         throw new TestException();
     }