gRPC: add an option to not start server in dev mode

fixes quarkusio#19721

extensions/grpc/deployment/src/main/java/io/quarkus/grpc/deployment/GrpcBuildTimeConfig.java

@@ -12,4 +12,11 @@ public class GrpcBuildTimeConfig {
     @ConfigItem(name = "metrics.enabled")
     public boolean metricsEnabled;
 
+    /**
+     * Start gRPC server in dev mode even if no gRPC services are implemented.
+     * By default set to `true` to ease incremental development of new services using dev mode.
+     */
+    @ConfigItem(name = "dev-force-server-start", defaultValue = "true")
+    public boolean devForceServerStart;
+
 }

extensions/grpc/deployment/src/main/java/io/quarkus/grpc/deployment/GrpcServerProcessor.java

@@ -466,8 +466,11 @@ private GrpcInterceptors gatherInterceptors(IndexView index) {
     @BuildStep
     @Record(value = ExecutionTime.RUNTIME_INIT)
     @Consume(SyntheticBeansRuntimeInitBuildItem.class)
-    ServiceStartBuildItem initializeServer(GrpcServerRecorder recorder, GrpcConfiguration config,
-            ShutdownContextBuildItem shutdown, List<BindableServiceBuildItem> bindables,
+    ServiceStartBuildItem initializeServer(GrpcServerRecorder recorder,
+            GrpcConfiguration config,
+            GrpcBuildTimeConfig buildTimeConfig,
+            ShutdownContextBuildItem shutdown,
+            List<BindableServiceBuildItem> bindables,
             LaunchModeBuildItem launchModeBuildItem,
             VertxBuildItem vertx) {
 
@@ -479,7 +482,7 @@ ServiceStartBuildItem initializeServer(GrpcServerRecorder recorder, GrpcConfigur
             }
         }
 
-        if (!bindables.isEmpty() || LaunchMode.current() == LaunchMode.DEVELOPMENT) {
+        if (!bindables.isEmpty() || (LaunchMode.current() == LaunchMode.DEVELOPMENT && buildTimeConfig.devForceServerStart)) {
             recorder.initializeGrpcServer(vertx.getVertx(), config, shutdown, blocking, launchModeBuildItem.getLaunchMode());
             return new ServiceStartBuildItem(GRPC_SERVER);
         }
@@ -550,7 +553,7 @@ void configureMetrics(GrpcBuildTimeConfig configuration, Optional<MetricsCapabil
 
     @BuildStep
     BeanArchivePredicateBuildItem additionalBeanArchives() {
-        return new BeanArchivePredicateBuildItem(new Predicate<ApplicationArchive>() {
+        return new BeanArchivePredicateBuildItem(new Predicate<>() {
 
             @Override
             public boolean test(ApplicationArchive archive) {

extensions/grpc/deployment/src/test/java/io/quarkus/grpc/server/devmode/DevModeServerStartDisabledTest.java

@@ -0,0 +1,26 @@
+package io.quarkus.grpc.server.devmode;
+
+import static io.restassured.RestAssured.when;
+
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.asset.StringAsset;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.test.QuarkusDevModeTest;
+import io.restassured.response.Response;
+
+public class DevModeServerStartDisabledTest {
+    @RegisterExtension
+    public static final QuarkusDevModeTest config = new QuarkusDevModeTest()
+            .setArchiveProducer(() -> ShrinkWrap.create(JavaArchive.class)
+                    .addClasses(IsUpEndpoint.class)
+                    .add(new StringAsset("quarkus.grpc.dev-force-server-start=false\n"), "application.properties"));
+
+    @Test
+    public void test() {
+        Response response = when().get("/grpc-status");
+        response.then().statusCode(204); // 200 is returned when server started, 204 otherwise
+    }
+}

extensions/grpc/deployment/src/test/java/io/quarkus/grpc/server/devmode/DevModeServerStartTest.java

@@ -0,0 +1,25 @@
+package io.quarkus.grpc.server.devmode;
+
+import static io.restassured.RestAssured.when;
+
+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.quarkus.test.QuarkusDevModeTest;
+import io.restassured.response.Response;
+
+public class DevModeServerStartTest {
+
+    @RegisterExtension
+    static final QuarkusDevModeTest config = new QuarkusDevModeTest()
+            .setArchiveProducer(() -> ShrinkWrap.create(JavaArchive.class)
+                    .addClasses(IsUpEndpoint.class));
+
+    @Test
+    public void test() {
+        Response response = when().get("/grpc-status");
+        response.then().statusCode(200); // 200 is returned when server started, 204 otherwise
+    }
+}

extensions/grpc/deployment/src/test/java/io/quarkus/grpc/server/devmode/IsUpEndpoint.java

@@ -0,0 +1,18 @@
+package io.quarkus.grpc.server.devmode;
+
+import javax.enterprise.context.ApplicationScoped;
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.core.Response;
+
+import io.quarkus.grpc.runtime.GrpcServerRecorder;
+
+@Path("/grpc-status")
+@ApplicationScoped
+public class IsUpEndpoint {
+    @GET
+    public Response isGrpcUp() {
+        return GrpcServerRecorder.getVerticleCount() > 0 ? Response.ok().build() : Response.noContent().build();
+    }
+
+}