Micrometer: allow veto of default MeterRegistry

extensions/micrometer/deployment/src/main/java/io/quarkus/micrometer/deployment/MicrometerProcessor.java

@@ -1,5 +1,6 @@
 package io.quarkus.micrometer.deployment;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
@@ -96,6 +97,8 @@ MetricsCapabilityBuildItem metricsCapabilityPrometheusBuildItem(
     @BuildStep(onlyIf = MicrometerEnabled.class)
     UnremovableBeanBuildItem registerAdditionalBeans(CombinedIndexBuildItem indexBuildItem,
             BuildProducer<MicrometerRegistryProviderBuildItem> providerClasses,
+            BuildProducer<AnnotationsTransformerBuildItem> annotationsTransformers,
+            List<VetoDefaultMeterRegistryBuildItem> vetoedRegistries,
             BuildProducer<ReflectiveClassBuildItem> reflectiveClasses,
             BuildProducer<AdditionalBeanBuildItem> additionalBeans) {
 
@@ -121,7 +124,7 @@ UnremovableBeanBuildItem registerAdditionalBeans(CombinedIndexBuildItem indexBui
         IndexView index = indexBuildItem.getIndex();
 
         // Find classes that define MeterRegistries, MeterBinders, and MeterFilters
-        Collection<String> knownRegistries = new HashSet<>();
+        final Collection<String> knownRegistries = new HashSet<>();
         collectNames(index.getAllKnownSubclasses(METER_REGISTRY), knownRegistries);
 
         Collection<String> knownClasses = new HashSet<>();
@@ -164,6 +167,34 @@ UnremovableBeanBuildItem registerAdditionalBeans(CombinedIndexBuildItem indexBui
             }
         }
 
+        if (vetoedRegistries.size() > 0) {
+            List<DotName> vetoedClassNames = new ArrayList<>();
+            for (VetoDefaultMeterRegistryBuildItem x : vetoedRegistries) {
+                vetoedClassNames.add(x.meterRegistryProducerClassName);
+            }
+
+            annotationsTransformers.produce(new AnnotationsTransformerBuildItem(new AnnotationsTransformer() {
+                @Override
+                public boolean appliesTo(AnnotationTarget.Kind kind) {
+                    return kind == org.jboss.jandex.AnnotationTarget.Kind.METHOD;
+                }
+
+                @Override
+                public void transform(TransformationContext ctx) {
+                    MethodInfo method = ctx.getTarget().asMethod();
+
+                    // if this targets a class in the vetoedRegistries list
+                    // and the method produces a known MeterRegistry type
+                    // and it is a @Produces method .. "veto it" -- remove Produces annotation
+                    if (vetoedClassNames.contains(method.declaringClass().name())
+                            && knownRegistries.contains(method.returnType().name().toString())
+                            && method.hasAnnotation(DotNames.PRODUCES)) {
+                        ctx.transform().removeAll().done();
+                    }
+                }
+            }));
+        }
+
         reflectiveClasses.produce(createReflectiveBuildItem(COUNTED_ANNOTATION, index));
         reflectiveClasses.produce(createReflectiveBuildItem(TIMED_ANNOTATION, index));
         reflectiveClasses.produce(ReflectiveClassBuildItem

extensions/micrometer/deployment/src/main/java/io/quarkus/micrometer/deployment/VetoDefaultMeterRegistryBuildItem.java

@@ -0,0 +1,24 @@
+package io.quarkus.micrometer.deployment;
+
+import org.jboss.jandex.DotName;
+
+import io.quarkus.builder.item.MultiBuildItem;
+
+public final class VetoDefaultMeterRegistryBuildItem extends MultiBuildItem {
+    final DotName meterRegistryProducerClassName;
+
+    public VetoDefaultMeterRegistryBuildItem(Class<?> meterRegistryProducerClass) {
+        this(DotName.createSimple(meterRegistryProducerClass.getName()));
+    }
+
+    public VetoDefaultMeterRegistryBuildItem(DotName meterRegistryProducerClass) {
+        this.meterRegistryProducerClassName = meterRegistryProducerClass;
+    }
+
+    @Override
+    public String toString() {
+        return "VetoDefaultMeterRegistryBuildItem"
+                + "{meterRegistryProducerClassName=" + meterRegistryProducerClassName
+                + '}';
+    }
+}

extensions/micrometer/deployment/src/main/java/io/quarkus/micrometer/deployment/export/PrometheusRegistryProcessor.java

@@ -10,6 +10,7 @@
 import io.quarkus.deployment.annotations.ExecutionTime;
 import io.quarkus.deployment.annotations.Record;
 import io.quarkus.micrometer.deployment.MicrometerRegistryProviderBuildItem;
+import io.quarkus.micrometer.deployment.VetoDefaultMeterRegistryBuildItem;
 import io.quarkus.micrometer.runtime.MicrometerRecorder;
 import io.quarkus.micrometer.runtime.config.MicrometerConfig;
 import io.quarkus.micrometer.runtime.config.PrometheusConfigGroup;
@@ -39,13 +40,21 @@ public boolean getAsBoolean() {
 
     @BuildStep(onlyIf = PrometheusEnabled.class)
     MicrometerRegistryProviderBuildItem createPrometheusRegistry(
+            MicrometerConfig mConfig,
+            BuildProducer<VetoDefaultMeterRegistryBuildItem> vetoedRegistries,
             BuildProducer<AdditionalBeanBuildItem> additionalBeans) {
 
         // Add the Prometheus Registry Producer
         additionalBeans.produce(AdditionalBeanBuildItem.builder()
                 .addBeanClass(PrometheusMeterRegistryProvider.class)
                 .setUnremovable().build());
 
+        PrometheusConfigGroup pConfig = mConfig.export.prometheus;
+        if (!pConfig.defaultRegistry) {
+            log.info("Default Prometheus MeterRegistry is disabled.");
+            vetoedRegistries.produce(new VetoDefaultMeterRegistryBuildItem(PrometheusMeterRegistryProvider.class));
+        }
+
         // Include the PrometheusMeterRegistry in a possible CompositeMeterRegistry
         return new MicrometerRegistryProviderBuildItem(REGISTRY_CLASS);
     }

extensions/micrometer/deployment/src/test/java/io/quarkus/micrometer/deployment/export/NoDefaultPrometheusTest.java

@@ -0,0 +1,55 @@
+package io.quarkus.micrometer.deployment.export;
+
+import java.util.Set;
+
+import javax.inject.Inject;
+
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
+import io.micrometer.prometheus.PrometheusMeterRegistry;
+import io.quarkus.micrometer.test.Util;
+import io.quarkus.test.QuarkusUnitTest;
+
+public class NoDefaultPrometheusTest {
+    @RegisterExtension
+    static final QuarkusUnitTest config = new QuarkusUnitTest()
+            .setFlatClassPath(true)
+            .withConfigurationResource("test-logging.properties")
+            .overrideConfigKey("quarkus.micrometer.binder-enabled-default", "false")
+            .overrideConfigKey("quarkus.micrometer.export.prometheus.enabled", "true")
+            .overrideConfigKey("quarkus.micrometer.export.prometheus.default-registry", "false")
+            .overrideConfigKey("quarkus.micrometer.registry-enabled-default", "false")
+            .setArchiveProducer(() -> ShrinkWrap.create(JavaArchive.class)
+                    .addClasses(Util.class,
+                            PrometheusRegistryProcessor.REGISTRY_CLASS,
+                            SecondPrometheusProvider.class));
+
+    @Inject
+    MeterRegistry registry;
+
+    @Inject
+    PrometheusMeterRegistry promRegistry;
+
+    @Test
+    public void testMeterRegistryPresent() {
+        // Prometheus is enabled (only registry)
+        Assertions.assertNotNull(registry, "A registry should be configured");
+        Set<MeterRegistry> subRegistries = ((CompositeMeterRegistry) registry).getRegistries();
+
+        PrometheusMeterRegistry subPromRegistry = (PrometheusMeterRegistry) subRegistries.iterator().next();
+        Assertions.assertEquals(PrometheusMeterRegistry.class, subPromRegistry.getClass(), "Should be PrometheusMeterRegistry");
+        Assertions.assertEquals(subPromRegistry, promRegistry,
+                "The only MeterRegistry should be the same bean as the PrometheusMeterRegistry");
+
+        String result = promRegistry.scrape();
+        Assertions.assertTrue(result.contains("customKey=\"customValue\""),
+                "Scrape result should contain common tags from the custom registry configration. Found\n" + result);
+
+    }
+}

extensions/micrometer/deployment/src/test/java/io/quarkus/micrometer/deployment/export/PrometheusEnabledTest.java

@@ -23,8 +23,7 @@ public class PrometheusEnabledTest {
             .overrideConfigKey("quarkus.micrometer.binder-enabled-default", "false")
             .overrideConfigKey("quarkus.micrometer.export.prometheus.enabled", "true")
             .overrideConfigKey("quarkus.micrometer.registry-enabled-default", "false")
-            .setArchiveProducer(() -> ShrinkWrap.create(JavaArchive.class)
-                    .addClass(PrometheusRegistryProcessor.REGISTRY_CLASS));
+            .setArchiveProducer(() -> ShrinkWrap.create(JavaArchive.class));
 
     @Inject
     MeterRegistry registry;

extensions/micrometer/deployment/src/test/java/io/quarkus/micrometer/deployment/export/SecondPrometheusProvider.java

@@ -13,6 +13,9 @@ public class SecondPrometheusProvider {
     @Produces
     @Singleton
     public PrometheusMeterRegistry registry(CollectorRegistry collectorRegistry, Clock clock) {
-        return new PrometheusMeterRegistry(PrometheusConfig.DEFAULT, collectorRegistry, clock);
+        PrometheusMeterRegistry customRegistry = new PrometheusMeterRegistry(PrometheusConfig.DEFAULT, collectorRegistry,
+                clock);
+        customRegistry.config().commonTags("customKey", "customValue");
+        return customRegistry;
     }
 }

extensions/micrometer/runtime/src/main/java/io/quarkus/micrometer/runtime/MicrometerRecorder.java

@@ -95,7 +95,7 @@ public void configureRegistries(MicrometerConfig config,
                     .getReference(i, MeterRegistry.class, beanManager.createCreationalContext(i));
 
             // Add & configure non-root registries
-            if (registry != Metrics.globalRegistry) {
+            if (registry != Metrics.globalRegistry && registry != null) {
                 applyMeterFilters(registry, globalFilters);
                 applyMeterFilters(registry, classMeterFilters.get(registry.getClass()));
                 log.debugf("Adding configured registry %s", registry.getClass(), registry);

extensions/micrometer/runtime/src/main/java/io/quarkus/micrometer/runtime/config/PrometheusConfigGroup.java

@@ -25,6 +25,14 @@ public class PrometheusConfigGroup implements MicrometerConfig.CapabilityEnabled
     @ConfigItem(defaultValue = "metrics")
     public String path;
 
+    /**
+     * By default, this extension will create a Prometheus MeterRegistry instance.
+     * <p>
+     * Use this attribute to veto the creation of the default Prometheus MeterRegistry.
+     */
+    @ConfigItem(defaultValue = "true")
+    public boolean defaultRegistry;
+
     @Override
     public Optional<Boolean> getEnabled() {
         return enabled;
@@ -35,6 +43,7 @@ public String toString() {
         return this.getClass().getSimpleName()
                 + "{path='" + path
                 + ",enabled=" + enabled
+                + ",defaultRegistry=" + defaultRegistry
                 + '}';
     }
 }