Allows applications to expose management endpoints

docs/src/main/asciidoc/management-interface-reference.adoc

@@ -84,7 +84,10 @@ The `quarkus.http.root-path` property is only applied to the main HTTP server an
 In addition, the `quarkus.http.non-application-root-path` property is not used for endpoint exposed on the management interface.
 ====
 
-== Create a management endpoint
+[[management-endpoint-extension]]
+== Create a management endpoint in an extension
+
+NOTE: To expose an endpoint on the management interface from the code of an application, refer to xref:#management-endpoint-application[the application section].
 
 SmallRye Health Checks, SmallRye Metrics, and Micrometer endpoints will be declared as management endpoints when the management interface is enabled.
 
@@ -114,6 +117,31 @@ Otherwise, it will be exposed on: `http://localhost:8080/q/my-path`.
 
 IMPORTANT: Management endpoints can only be declared by extensions and not from the application code.
 
+[[management-endpoint-application]]
+== Exposing an endpoint on the management interface (as an application)
+
+You can expose endpoints on the management interface by registering routes on the management router.
+To access the router use the following code:
+
+[source,java]
+----
+public void registerManagementRoutes(@Observes ManagementInterface mi) {
+       mi.router().get("/admin").handler(rc ->
+            rc.response().end("admin it is")
+       );
+}
+----
+
+The `io.quarkus.vertx.http.ManagementInterface` event is fired when the management interface is initialized.
+So, if the management interface is not enabled, the method won't be called.
+
+The `router()` method returns a `io.vertx.ext.web.Router` object which can be used to register routes.
+The paths are relative to `/`.
+For example, the previous snippet registers a route on `/admin`.
+This route is accessible on `http://0.0.0.0:9000/admin`, if you use the default host and port.
+
+More details about the `Router` API can be found on https://vertx.io/docs/vertx-web/java/[the Vert.x Web documentation].
+
 == Management Interface Configuration
 
 include::{generated-dir}/config/quarkus-management-management-management-interface-build-time-config.adoc[leveloffset=+1, opts=optional]

extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/ManagementInterface.java

@@ -0,0 +1,18 @@
+package io.quarkus.vertx.http;
+
+import io.vertx.ext.web.Router;
+
+/**
+ * A class allowing to access the management router.
+ * You can access the instance of this class using a CDI observer:
+ * {@code public void init(@Observe ManagementInterface mi) {...}}
+ * <p>
+ * If the management interface is disabled, the event is not fired.
+ */
+public interface ManagementInterface {
+
+    /**
+     * @return the management router
+     */
+    Router router();
+}

extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/ManagementInterfaceImpl.java

@@ -0,0 +1,18 @@
+package io.quarkus.vertx.http.runtime;
+
+import io.quarkus.vertx.http.ManagementInterface;
+import io.vertx.ext.web.Router;
+
+public class ManagementInterfaceImpl implements ManagementInterface {
+
+    private final Router router;
+
+    public ManagementInterfaceImpl(Router router) {
+        this.router = router;
+    }
+
+    @Override
+    public Router router() {
+        return router;
+    }
+}

extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/VertxHttpRecorder.java

@@ -29,6 +29,7 @@
 import java.util.regex.Pattern;
 
 import jakarta.enterprise.event.Event;
+import jakarta.enterprise.inject.Default;
 
 import org.crac.Resource;
 import org.jboss.logging.Logger;
@@ -60,6 +61,7 @@
 import io.quarkus.vertx.core.runtime.VertxCoreRecorder;
 import io.quarkus.vertx.core.runtime.config.VertxConfiguration;
 import io.quarkus.vertx.http.HttpServerOptionsCustomizer;
+import io.quarkus.vertx.http.ManagementInterface;
 import io.quarkus.vertx.http.runtime.HttpConfiguration.InsecureRequests;
 import io.quarkus.vertx.http.runtime.devmode.RemoteSyncHandler;
 import io.quarkus.vertx.http.runtime.devmode.VertxHttpHotReplacementSetup;
@@ -380,7 +382,7 @@ public void finalizeRouter(BeanContainer container, Consumer<Route> defaultRoute
         filterList.addAll(filters.getFilters());
 
         // Then, fire the resuming router
-        event.select(Router.class).fire(httpRouteRouter);
+        event.select(Router.class, Default.Literal.INSTANCE).fire(httpRouteRouter);
         // Also fires the Mutiny one
         event.select(io.vertx.mutiny.ext.web.Router.class).fire(mutinyRouter.getValue());
 
@@ -550,6 +552,8 @@ public void handle(RoutingContext event) {
             Handler<HttpServerRequest> handler = HttpServerCommonHandlers.enforceDuplicatedContext(mr);
             handler = HttpServerCommonHandlers.applyProxy(managementConfiguration.getValue().proxy, handler, vertx);
 
+            event.select(ManagementInterface.class).fire(new ManagementInterfaceImpl(managementRouter.getValue()));
+
             VertxHttpRecorder.managementRouter = handler;
         }
     }

integration-tests/management-interface/src/main/java/io/quarkus/it/management/GreetingResource.java

@@ -1,8 +1,12 @@
 package io.quarkus.it.management;
 
+import jakarta.enterprise.event.Observes;
 import jakarta.ws.rs.GET;
 import jakarta.ws.rs.Path;
 
+import io.quarkus.vertx.http.ManagementInterface;
+import io.vertx.ext.web.Router;
+
 @Path("/service")
 public class GreetingResource {
 
@@ -17,4 +21,12 @@ public String hello() {
     public String goodbye() {
         return "goodbye";
     }
+
+    public void initManagement(@Observes ManagementInterface mi) {
+        mi.router().get("/admin").handler(rc -> rc.response().end("admin it is"));
+    }
+
+    public void initMain(@Observes Router router) {
+        router.get("/main").handler(rc -> rc.response().end("main"));
+    }
 }

integration-tests/management-interface/src/test/java/io/quarkus/it/management/ManagementInterfaceTestCase.java

@@ -1,6 +1,7 @@
 package io.quarkus.it.management;
 
 import org.hamcrest.Matchers;
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 import io.quarkus.test.junit.QuarkusTest;
@@ -33,4 +34,24 @@ void verifyThatMetricsAreExposedOnManagementInterface() {
                 .then().statusCode(404);
     }
 
+    @Test
+    void verifyAccessToTheManagementInterface() {
+        String s = RestAssured.get(getPrefix() + "/admin")
+                .then().statusCode(200)
+                .extract()
+                .asString();
+        Assertions.assertEquals("admin it is", s);
+
+        s = RestAssured.get("/main")
+                .then().statusCode(200)
+                .extract()
+                .asString();
+        Assertions.assertEquals("main", s);
+
+        RestAssured.get("/admin")
+                .then().statusCode(404);
+        RestAssured.get(getPrefix() + "/main")
+                .then().statusCode(404);
+    }
+
 }

integration-tests/vertx-http/src/main/java/io/quarkus/it/vertx/NoManagementInterfaceRoute.java

@@ -0,0 +1,29 @@
+package io.quarkus.it.vertx;
+
+import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.enterprise.event.Observes;
+
+import io.quarkus.vertx.http.ManagementInterface;
+import io.vertx.ext.web.Router;
+
+@ApplicationScoped
+public class NoManagementInterfaceRoute {
+
+    boolean exposed;
+
+    void initMain(@Observes Router router) {
+        router.get("/management-interface-test").handler(rc -> {
+            if (exposed) {
+                rc.response().setStatusCode(500).end("KO");
+            } else {
+                rc.response().end("OK");
+            }
+        });
+    }
+
+    void init(@Observes ManagementInterface mi) {
+        exposed = true;
+        mi.router().get("/admin").handler(rc -> rc.response().end("admin it is"));
+    }
+
+}

integration-tests/vertx-http/src/test/java/io/quarkus/it/vertx/VertxProducerResourceTest.java

@@ -36,6 +36,11 @@ public void testRouteRegistration() {
         get("/my-path").then().body(containsString("OK"));
     }
 
+    @Test
+    public void testManagementInterfaceMissing() {
+        get("/management-interface-test").then().body(containsString("OK"));
+    }
+
     @Test
     public void testRouteRegistrationMTLS() {
         RequestSpecification spec = new RequestSpecBuilder()