@UnlessBuildProperty to suppress default instance

extensions/arc/deployment/src/main/java/io/quarkus/arc/deployment/BuildTimeEnabledProcessor.java

@@ -271,9 +271,9 @@ private void transformBean(AnnotationTarget target, TransformationContext ctx, b
             } else {
                 // Add @Alternative to the producer
                 transform.add(DotNames.ALTERNATIVE);
+                transform.remove(s -> s.name().equals(DotNames.ALTERNATIVE_PRIORITY));
             }
             transform.done();
         }
     }
-
 }

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

@@ -0,0 +1,58 @@
+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();
+        Assertions.assertEquals(1, subRegistries.size(),
+                "There should be only one configured subregistry. Found " + subRegistries);
+
+        PrometheusMeterRegistry subPromRegistry = (PrometheusMeterRegistry) subRegistries.iterator().next();
+        Assertions.assertEquals(PrometheusMeterRegistry.class, subPromRegistry.getClass(),
+                "Should be PrometheusMeterRegistry");
+        Assertions.assertEquals(subPromRegistry, promRegistry,
+                "Should be the same bean as the PrometheusMeterRegistry. Found " + subRegistries);
+
+        String result = promRegistry.scrape();
+        Assertions.assertTrue(result.contains("customKey=\"customValue\""),
+                "Scrape result should contain common tags from the custom registry configuration. 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;
@@ -37,9 +36,13 @@ public void testMeterRegistryPresent() {
         // Prometheus is enabled (only registry)
         Assertions.assertNotNull(registry, "A registry should be configured");
         Set<MeterRegistry> subRegistries = ((CompositeMeterRegistry) registry).getRegistries();
+        Assertions.assertEquals(1, subRegistries.size(),
+                "There should be only one configured subregistry. Found " + subRegistries);
+
         PrometheusMeterRegistry subPromRegistry = (PrometheusMeterRegistry) subRegistries.iterator().next();
-        Assertions.assertEquals(PrometheusMeterRegistry.class, subPromRegistry.getClass(), "Should be PrometheusMeterRegistry");
+        Assertions.assertEquals(PrometheusMeterRegistry.class, subPromRegistry.getClass(),
+                "Should be PrometheusMeterRegistry");
         Assertions.assertEquals(subPromRegistry, promRegistry,
-                "The only MeterRegistry should be the same bean as the PrometheusMeterRegistry");
+                "Should be the same bean as the injected PrometheusMeterRegistry");
     }
 }

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
                 + '}';
     }
 }

extensions/micrometer/runtime/src/main/java/io/quarkus/micrometer/runtime/export/PrometheusMeterRegistryProvider.java

@@ -17,6 +17,7 @@
 import io.prometheus.client.CollectorRegistry;
 import io.quarkus.arc.AlternativePriority;
 import io.quarkus.arc.DefaultBean;
+import io.quarkus.arc.properties.UnlessBuildProperty;
 
 @Singleton
 public class PrometheusMeterRegistryProvider {
@@ -58,6 +59,7 @@ public CollectorRegistry collectorRegistry() {
 
     @Produces
     @Singleton
+    @UnlessBuildProperty(name = "quarkus.micrometer.export.prometheus.default-registry", stringValue = "false", enableIfMissing = true)
     @AlternativePriority(Interceptor.Priority.APPLICATION + 100)
     public PrometheusMeterRegistry registry(PrometheusConfig config, CollectorRegistry collectorRegistry, Clock clock) {
         return new PrometheusMeterRegistry(config, collectorRegistry, clock);