Add Prometheus annotations when smallrye metrics in enabled

extensions/kubernetes/vanilla/deployment/pom.xml

@@ -29,6 +29,10 @@
             <groupId>io.quarkus</groupId>
             <artifactId>quarkus-kubernetes-client-deployment-internal</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-smallrye-metrics-spi</artifactId>
+        </dependency>
         <dependency>
             <groupId>io.dekorate</groupId>
             <artifactId>kubernetes-annotations</artifactId>

extensions/kubernetes/vanilla/deployment/src/main/java/io/quarkus/kubernetes/deployment/Annotations.java

@@ -0,0 +1,19 @@
+package io.quarkus.kubernetes.deployment;
+
+final class Annotations {
+
+    private Annotations() {
+    }
+
+    static final class Prometheus {
+
+        private Prometheus() {
+        }
+
+        private static final String PREFIX = "prometheus.io/";
+
+        static final String SCRAPE = PREFIX + "scrape";
+        static final String PATH = PREFIX + "path";
+        static final String PORT = PREFIX + "port";
+    }
+}

extensions/kubernetes/vanilla/deployment/src/main/java/io/quarkus/kubernetes/deployment/KubernetesProcessor.java

@@ -55,7 +55,17 @@
 import io.quarkus.deployment.pkg.PackageConfig;
 import io.quarkus.deployment.pkg.builditem.OutputTargetBuildItem;
 import io.quarkus.deployment.util.FileUtil;
-import io.quarkus.kubernetes.spi.*;
+import io.quarkus.kubernetes.deployment.Annotations.Prometheus;
+import io.quarkus.kubernetes.spi.KubernetesAnnotationBuildItem;
+import io.quarkus.kubernetes.spi.KubernetesCommandBuildItem;
+import io.quarkus.kubernetes.spi.KubernetesDeploymentTargetBuildItem;
+import io.quarkus.kubernetes.spi.KubernetesEnvBuildItem;
+import io.quarkus.kubernetes.spi.KubernetesHealthLivenessPathBuildItem;
+import io.quarkus.kubernetes.spi.KubernetesHealthReadinessPathBuildItem;
+import io.quarkus.kubernetes.spi.KubernetesLabelBuildItem;
+import io.quarkus.kubernetes.spi.KubernetesPortBuildItem;
+import io.quarkus.kubernetes.spi.KubernetesRoleBuildItem;
+import io.quarkus.smallrye.metrics.deployment.spi.MetricsConfigurationBuildItem;
 
 class KubernetesProcessor {
 
@@ -118,12 +128,28 @@ public EnabledKubernetesDeploymentTargetsBuildItem enabledKubernetesDeploymentTa
 
     @BuildStep
     public List<KubernetesAnnotationBuildItem> createAnnotations(KubernetesConfig kubernetesConfig,
-            OpenshiftConfig openshiftConfig, KnativeConfig knativeConfig) {
-        List<KubernetesAnnotationBuildItem> items = new ArrayList<KubernetesAnnotationBuildItem>();
-        kubernetesConfig.annotations.forEach((k, v) -> items.add(new KubernetesAnnotationBuildItem(k, v, KUBERNETES)));
-        openshiftConfig.annotations.forEach((k, v) -> items.add(new KubernetesAnnotationBuildItem(k, v, OPENSHIFT)));
-        knativeConfig.annotations.forEach((k, v) -> items.add(new KubernetesAnnotationBuildItem(k, v, KNATIVE)));
-        return items;
+            OpenshiftConfig openshiftConfig, KnativeConfig knativeConfig,
+            Optional<MetricsConfigurationBuildItem> metricsConfiguration, List<KubernetesPortBuildItem> kubernetesPorts) {
+        List<KubernetesAnnotationBuildItem> result = new ArrayList<KubernetesAnnotationBuildItem>();
+        addAnnotations(kubernetesConfig, KUBERNETES, metricsConfiguration, kubernetesPorts, result);
+        addAnnotations(openshiftConfig, OPENSHIFT, metricsConfiguration, kubernetesPorts, result);
+        addAnnotations(knativeConfig, KNATIVE, metricsConfiguration, kubernetesPorts, result);
+        return result;
+    }
+
+    private void addAnnotations(PlatformConfiguration config, String target,
+            Optional<MetricsConfigurationBuildItem> metricsConfigurationBuildItem,
+            List<KubernetesPortBuildItem> kubernetesPorts,
+            List<KubernetesAnnotationBuildItem> result) {
+        for (Map.Entry<String, String> entry : config.getAnnotations().entrySet()) {
+            result.add(new KubernetesAnnotationBuildItem(entry.getKey(), entry.getValue(), target));
+        }
+        if (metricsConfigurationBuildItem.isPresent() && !kubernetesPorts.isEmpty()) {
+            result.add(new KubernetesAnnotationBuildItem(Prometheus.SCRAPE, "true", target));
+            result.add(new KubernetesAnnotationBuildItem(Prometheus.PATH, metricsConfigurationBuildItem.get().getPath(),
+                    target));
+            result.add(new KubernetesAnnotationBuildItem(Prometheus.PORT, "" + kubernetesPorts.get(0).getPort(), target));
+        }
     }
 
     @BuildStep

extensions/smallrye-metrics/deployment/src/main/java/io/quarkus/smallrye/metrics/deployment/SmallRyeMetricsProcessor.java

@@ -70,6 +70,7 @@
 import io.quarkus.smallrye.metrics.deployment.jandex.JandexBeanInfoAdapter;
 import io.quarkus.smallrye.metrics.deployment.jandex.JandexMemberInfoAdapter;
 import io.quarkus.smallrye.metrics.deployment.spi.MetricBuildItem;
+import io.quarkus.smallrye.metrics.deployment.spi.MetricsConfigurationBuildItem;
 import io.quarkus.smallrye.metrics.runtime.MetadataHolder;
 import io.quarkus.smallrye.metrics.runtime.SmallRyeMetricsRecorder;
 import io.quarkus.smallrye.metrics.runtime.TagHolder;
@@ -123,6 +124,11 @@ static final class SmallRyeMetricsConfig {
 
     SmallRyeMetricsConfig metrics;
 
+    @BuildStep
+    MetricsConfigurationBuildItem metricsConfigurationBuildItem() {
+        return new MetricsConfigurationBuildItem(metrics.path);
+    }
+
     @BuildStep
     @Record(STATIC_INIT)
     void createRoute(BuildProducer<RouteBuildItem> routes,

extensions/smallrye-metrics/spi/src/main/java/io/quarkus/smallrye/metrics/deployment/spi/MetricsConfigurationBuildItem.java

@@ -0,0 +1,19 @@
+package io.quarkus.smallrye.metrics.deployment.spi;
+
+import io.quarkus.builder.item.SimpleBuildItem;
+
+/**
+ * A build item that can be used by build steps that need to know the metrics configuration
+ */
+public final class MetricsConfigurationBuildItem extends SimpleBuildItem {
+
+    private final String path;
+
+    public MetricsConfigurationBuildItem(String path) {
+        this.path = path;
+    }
+
+    public String getPath() {
+        return path;
+    }
+}

integration-tests/kubernetes/quarkus-standard-way/src/test/java/io/quarkus/it/kubernetes/KubernetesWithMetricsTest.java

@@ -0,0 +1,83 @@
+package io.quarkus.it.kubernetes;
+
+import static io.restassured.RestAssured.given;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
+import static org.hamcrest.Matchers.is;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.Collections;
+import java.util.List;
+
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.fabric8.kubernetes.api.model.apps.Deployment;
+import io.quarkus.bootstrap.model.AppArtifact;
+import io.quarkus.builder.Version;
+import io.quarkus.test.LogFile;
+import io.quarkus.test.ProdBuildResults;
+import io.quarkus.test.ProdModeTestResults;
+import io.quarkus.test.QuarkusProdModeTest;
+
+public class KubernetesWithMetricsTest {
+
+    @RegisterExtension
+    static final QuarkusProdModeTest config = new QuarkusProdModeTest()
+            .setArchiveProducer(() -> ShrinkWrap.create(JavaArchive.class).addClasses(GreetingResource.class))
+            .setApplicationName("health")
+            .setApplicationVersion("0.1-SNAPSHOT")
+            .setRun(true)
+            .setLogFileName("k8s.log")
+            .withConfigurationResource("kubernetes-with-metrics.properties")
+            .setForcedDependencies(
+                    Collections.singletonList(
+                            new AppArtifact("io.quarkus", "quarkus-smallrye-metrics", Version.getVersion())));
+
+    @ProdBuildResults
+    private ProdModeTestResults prodModeTestResults;
+
+    @LogFile
+    private Path logfile;
+
+    @Test
+    public void assertApplicationRuns() {
+        assertThat(logfile).isRegularFile().hasFileName("k8s.log");
+        TestUtil.assertLogFileContents(logfile, "kubernetes", "metrics");
+
+        given()
+                .when().get("/greeting")
+                .then()
+                .statusCode(200)
+                .body(is("hello"));
+    }
+
+    @Test
+    public void assertGeneratedResources() throws IOException {
+        final Path kubernetesDir = prodModeTestResults.getBuildDir().resolve("kubernetes");
+        assertThat(kubernetesDir)
+                .isDirectoryContaining(p -> p.getFileName().endsWith("kubernetes.json"))
+                .isDirectoryContaining(p -> p.getFileName().endsWith("kubernetes.yml"));
+        List<HasMetadata> kubernetesList = DeserializationUtil
+                .deserializeAsList(kubernetesDir.resolve("kubernetes.yml"));
+        assertThat(kubernetesList.get(0)).isInstanceOfSatisfying(Deployment.class, d -> {
+            assertThat(d.getMetadata()).satisfies(m -> {
+                assertThat(m.getName()).isEqualTo("health");
+            });
+
+            assertThat(d.getSpec()).satisfies(deploymentSpec -> {
+                assertThat(deploymentSpec.getTemplate()).satisfies(t -> {
+                    assertThat(t.getMetadata()).satisfies(meta -> {
+                        assertThat(meta.getAnnotations()).contains(entry("prometheus.io/scrape", "true"),
+                                entry("prometheus.io/path", "/met"), entry("prometheus.io/port", "9090"));
+                    });
+                });
+            });
+        });
+    }
+
+}

integration-tests/kubernetes/quarkus-standard-way/src/test/resources/kubernetes-with-metrics.properties

@@ -0,0 +1,2 @@
+quarkus.http.port=9090
+quarkus.smallrye-metrics.path=/met