#1: Autoconfigure metric registry support

Signed-off-by: Sunny <hmtang@gmail.com>
[resolves #1]

Author: hmtang

samples/grpc-server/src/test/java/org/springframework/grpc/sample/GrpcServerApplicationTests.java

@@ -1,7 +1,9 @@
 package org.springframework.grpc.sample;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import io.micrometer.core.instrument.MeterRegistry;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.junit.jupiter.api.Test;
@@ -30,6 +32,9 @@ public static void main(String[] args) {
 	@Autowired
 	private SimpleGrpc.SimpleBlockingStub stub;
 
+	@Autowired
+	private MeterRegistry meterRegistry;
+
 	@Test
 	@DirtiesContext
 	void contextLoads() {
@@ -43,6 +48,18 @@ void serverResponds() {
 		assertEquals("Hello ==> Alien", response.getMessage());
 	}
 
+	@Test
+	@DirtiesContext
+	void verifyMetrics() {
+		log.info("Verify stats are collected");
+		stub.sayHello(HelloRequest.newBuilder().setName("Alien").build());
+		assertThat(meterRegistry.get("grpc.server.requests.received").counter().count()).isEqualTo(1);
+		assertThat(meterRegistry.get("grpc.server.responses.sent").counter().count()).isEqualTo(1);
+		stub.sayHello(HelloRequest.newBuilder().setName("Jamie").build());
+		assertThat(meterRegistry.get("grpc.server.requests.received").counter().count()).isEqualTo(2);
+		assertThat(meterRegistry.get("grpc.server.responses.sent").counter().count()).isEqualTo(2);
+	}
+
 	@TestConfiguration
 	static class ExtraConfiguration {
 

spring-grpc-core/pom.xml

@@ -67,13 +67,23 @@
 			<artifactId>grpc-stub</artifactId>
 		</dependency>
 
+		<dependency>
+			<groupId>io.micrometer</groupId>
+			<artifactId>micrometer-core</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>io.micrometer</groupId>
+			<artifactId>micrometer-registry-prometheus</artifactId>
+		</dependency>
+
 		<dependency>
 			<groupId>org.junit.jupiter</groupId>
 			<artifactId>junit-jupiter</artifactId>
 			<version>${junit.version}</version>
 			<scope>test</scope>
 		</dependency>
 
+
 	</dependencies>
 
 

spring-grpc-core/src/main/java/org/springframework/grpc/server/DefaultGrpcServerFactory.java

@@ -23,16 +23,11 @@
 
 import com.google.common.collect.Lists;
 
-import io.grpc.Grpc;
-import io.grpc.InsecureServerCredentials;
-import io.grpc.Server;
-import io.grpc.ServerBuilder;
-import io.grpc.ServerCredentials;
-import io.grpc.ServerProvider;
-import io.grpc.ServerServiceDefinition;
+import io.grpc.*;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.grpc.internal.GrpcUtils;
 
 /**
@@ -56,6 +51,9 @@ public class DefaultGrpcServerFactory<T extends ServerBuilder<T>> implements Grp
 
 	private final List<ServerBuilderCustomizer<T>> serverBuilderCustomizers;
 
+	@Autowired
+	private List<ServerInterceptor> serverInterceptors;
+
 	public DefaultGrpcServerFactory(String address, List<ServerBuilderCustomizer<T>> serverBuilderCustomizers) {
 		this.address = address;
 		this.serverBuilderCustomizers = Objects.requireNonNull(serverBuilderCustomizers, "serverBuilderCustomizers");
@@ -83,7 +81,11 @@ public void addService(ServerServiceDefinition service) {
 	 */
 	@SuppressWarnings("unchecked")
 	protected T newServerBuilder() {
-		return (T) Grpc.newServerBuilderForPort(port(), credentials());
+		var builder = Grpc.newServerBuilderForPort(port(), credentials());
+		for (ServerInterceptor interceptor : serverInterceptors) {
+			builder.intercept(interceptor);
+		}
+		return (T) builder;
 	}
 
 	/**

spring-grpc-dependencies/pom.xml

@@ -54,6 +54,7 @@
 		<grpc.version>1.63.2</grpc.version>
 		<protobuf-java.version>3.25.5</protobuf-java.version>
 		<google-common-protos.version>2.46.0</google-common-protos.version>
+		<micrometer.version>1.13.6</micrometer.version>
 	</properties>
 
 	<dependencyManagement>
@@ -112,6 +113,16 @@
 				<artifactId>proto-google-common-protos</artifactId>
 				<version>${google-common-protos.version}</version>
 			</dependency>
+			<dependency>
+				<groupId>io.micrometer</groupId>
+				<artifactId>micrometer-core</artifactId>
+				<version>${micrometer.version}</version>
+			</dependency>
+			<dependency>
+				<groupId>io.micrometer</groupId>
+				<artifactId>micrometer-registry-prometheus</artifactId>
+				<version>${micrometer.version}</version>
+			</dependency>
 		</dependencies>
 	</dependencyManagement>
 

spring-grpc-spring-boot-autoconfigure/src/main/java/org/springframework/grpc/autoconfigure/server/GrpcServerAutoConfiguration.java

@@ -15,6 +15,10 @@
  */
 package org.springframework.grpc.autoconfigure.server;
 
+import io.grpc.ServerInterceptor;
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.binder.grpc.MetricCollectingServerInterceptor;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
@@ -69,4 +73,15 @@ ServerBuilderCustomizers serverBuilderCustomizers(ObjectProvider<ServerBuilderCu
 		return new ServerBuilderCustomizers(customizers.orderedStream().toList());
 	}
 
+	@ConditionalOnMissingBean
+	@Bean
+	public MeterRegistry meterRegistry() {
+		return new SimpleMeterRegistry();
+	}
+
+	@Bean
+	public ServerInterceptor metricCollectingServerInterceptor(MeterRegistry meterRegistry) {
+		return new MetricCollectingServerInterceptor(meterRegistry);
+	}
+
 }

spring-grpc-spring-boot-autoconfigure/src/test/java/org/springframework/grpc/autoconfigure/server/GrpcServerAutoConfigurationTests.java

@@ -27,6 +27,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 
+import io.micrometer.core.instrument.MeterRegistry;
 import org.assertj.core.api.InstanceOfAssertFactories;
 import org.junit.jupiter.api.Test;
 import org.mockito.InOrder;
@@ -246,6 +247,20 @@ void nettyServerFactoryAutoConfiguredWithSsl() {
 				NettyGrpcServerFactory.class);
 	}
 
+	@Test
+	void whenHasUserDefinedMeterRegistryDoesNotAutoConfigureBean() {
+		MeterRegistry customMeterRegistry = mock(MeterRegistry.class);
+		this.contextRunner()
+			.withBean("customMeterRegistry", MeterRegistry.class, () -> customMeterRegistry)
+			.run((context) -> assertThat(context).getBean(MeterRegistry.class).isSameAs(customMeterRegistry));
+	}
+
+	@Test
+	void serverMeterRegistryAutoConfiguredAsExpected() {
+		this.contextRunner()
+			.run((context) -> assertThat(context).getBean(MeterRegistry.class).hasFieldOrProperty("config"));
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class ServerBuilderCustomizersConfig {