Address deprecations in MP metrics for 3.x

examples/quickstarts/helidon-quickstart-mp/pom.xml

@@ -42,6 +42,10 @@
             <scope>runtime</scope>
             <optional>true</optional>
         </dependency>
+        <dependency>
+            <groupId>io.helidon.microprofile.grpc</groupId>
+            <artifactId>helidon-microprofile-grpc-metrics</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>

microprofile/grpc/metrics/pom.xml

@@ -42,6 +42,10 @@
             <groupId>io.helidon.microprofile.grpc</groupId>
             <artifactId>helidon-microprofile-grpc-server</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.helidon.common</groupId>
+            <artifactId>helidon-common-service-loader</artifactId>
+        </dependency>
         <dependency>
             <groupId>io.helidon.microprofile.metrics</groupId>
             <artifactId>helidon-microprofile-metrics</artifactId>

microprofile/grpc/metrics/src/main/java/io/helidon/microprofile/grpc/metrics/GrpcMetricAnnotationDiscoveryObserverImpl.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2022 Oracle and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.helidon.microprofile.grpc.metrics;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Method;
+import java.util.HashMap;
+import java.util.Map;
+
+import io.helidon.microprofile.grpc.core.AnnotatedMethod;
+import io.helidon.microprofile.grpc.core.GrpcMethod;
+import io.helidon.microprofile.metrics.MetricAnnotationDiscovery;
+import io.helidon.microprofile.metrics.spi.MetricAnnotationDiscoveryObserver;
+
+import jakarta.enterprise.inject.spi.configurator.AnnotatedMethodConfigurator;
+
+/**
+ * The gRPC implementation of {@link io.helidon.microprofile.metrics.spi.MetricAnnotationDiscoveryObserver}.
+ *
+ * <p>
+ *     This implementation
+ * </p>
+ */
+public class GrpcMetricAnnotationDiscoveryObserverImpl implements MetricAnnotationDiscoveryObserver {
+
+    private static GrpcMetricAnnotationDiscoveryObserverImpl instance;
+
+    static GrpcMetricAnnotationDiscoveryObserverImpl instance() {
+        return instance;
+    }
+
+    private static void instance(GrpcMetricAnnotationDiscoveryObserverImpl value) {
+        instance = value;
+    }
+
+    private final Map<Method,
+            Map<Class<? extends Annotation>, MetricAnnotationDiscovery.OfMethod>> discoveriesByMethod =
+            new HashMap<>();
+
+    /**
+     * Creates a new instance.
+     */
+    public GrpcMetricAnnotationDiscoveryObserverImpl() {
+        instance(this);
+    }
+
+    @Override
+    public void onDiscovery(MetricAnnotationDiscovery discovery) {
+        if (discovery instanceof MetricAnnotationDiscovery.OfMethod methodDiscovery
+            && isRpcMethod(methodDiscovery.configurator(), discovery.annotation().annotationType())) {
+
+            if (!MetricsConfigurer.isServiceAnnotated(methodDiscovery.annotatedTypeConfigurator().getAnnotated().getJavaClass(),
+                                                      methodDiscovery.configurator().getAnnotated().getJavaMember(),
+                                                      discovery.annotation().annotationType())) {
+                // This endpoint should not give rise to a gRPC-inspired metric.
+                discovery.deactivate();
+            } else {
+                // This endpoint SHOULD give rise to a gRPC-inspired metric.
+                discovery.disableDefaultInterceptor();
+                discoveriesByMethod.computeIfAbsent(methodDiscovery.configurator().getAnnotated().getJavaMember(),
+                                                    key -> new HashMap<>())
+                        .putIfAbsent(discovery.annotation().annotationType(), methodDiscovery);
+            }
+        }
+    }
+
+    Map<Class<? extends Annotation>, MetricAnnotationDiscovery.OfMethod> discoveries(Method method) {
+        return discoveriesByMethod.get(method);
+    }
+
+    boolean isDiscovered(Method method) {
+        return discoveriesByMethod.containsKey(method);
+    }
+
+    /**
+     * Determine whether a method is annotated with both a metrics annotation
+     * and an annotation of type {@link io.helidon.microprofile.grpc.core.GrpcMethod}.
+     *
+     * @param configurator  the {@link jakarta.enterprise.inject.spi.configurator.AnnotatedMethodConfigurator} representing
+     *                      the annotated method
+     *
+     * @return {@code true} if the method is a timed gRPC method
+     */
+    private static boolean isRpcMethod(AnnotatedMethodConfigurator<?> configurator, Class<? extends Annotation> type) {
+        AnnotatedMethod method = AnnotatedMethod.create(configurator.getAnnotated().getJavaMember());
+        GrpcMethod rpcMethod = method.firstAnnotationOrMetaAnnotation(GrpcMethod.class);
+        if (rpcMethod != null) {
+            Annotation annotation = method.firstAnnotationOrMetaAnnotation(type);
+            return annotation != null;
+        }
+        return false;
+    }
+
+}

microprofile/grpc/metrics/src/main/java/io/helidon/microprofile/grpc/metrics/GrpcMetricRegistrationObserverImpl.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2022 Oracle and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.helidon.microprofile.grpc.metrics;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import io.helidon.microprofile.metrics.MetricAnnotationDiscovery;
+import io.helidon.microprofile.metrics.spi.MetricRegistrationObserver;
+
+import org.eclipse.microprofile.metrics.Metadata;
+import org.eclipse.microprofile.metrics.Metric;
+import org.eclipse.microprofile.metrics.MetricID;
+
+/**
+ * The gRPC implementation of {@link io.helidon.microprofile.metrics.spi.MetricRegistrationObserver} with a static factory method.
+ */
+public class GrpcMetricRegistrationObserverImpl implements MetricRegistrationObserver {
+
+    private static GrpcMetricRegistrationObserverImpl instance;
+
+    static GrpcMetricRegistrationObserverImpl instance() {
+        return instance;
+    }
+
+    private static void instance(GrpcMetricRegistrationObserverImpl value) {
+        instance = value;
+    }
+
+    private final Map<MetricAnnotationDiscovery, Metadata> metadataByDiscovery = new HashMap<>();
+
+    /**
+     * Creates a new instance of the observer.
+     */
+    public GrpcMetricRegistrationObserverImpl() {
+        instance(this);
+    }
+
+    @Override
+    public void onRegistration(MetricAnnotationDiscovery discovery,
+                               Metadata metadata,
+                               MetricID metricId,
+                               Metric metric) {
+        metadataByDiscovery.put(discovery, metadata);
+    }
+
+    Metadata metadata(MetricAnnotationDiscovery discovery) {
+        return metadataByDiscovery.get(discovery);
+    }
+}