Create better response when no GraphQL endpoint has been generated

extensions/smallrye-graphql/deployment/src/main/java/io/quarkus/smallrye/graphql/deployment/SmallRyeGraphQLInitializedBuildItem.java

@@ -0,0 +1,17 @@
+package io.quarkus.smallrye.graphql.deployment;
+
+import io.quarkus.builder.item.SimpleBuildItem;
+import io.quarkus.runtime.RuntimeValue;
+
+final class SmallRyeGraphQLInitializedBuildItem extends SimpleBuildItem {
+
+    private final RuntimeValue<Boolean> initialized;
+
+    public SmallRyeGraphQLInitializedBuildItem(RuntimeValue<Boolean> initialized) {
+        this.initialized = initialized;
+    }
+
+    public RuntimeValue<Boolean> getInitialized() {
+        return initialized;
+    }
+}

extensions/smallrye-graphql/deployment/src/main/java/io/quarkus/smallrye/graphql/deployment/SmallRyeGraphQLProcessor.java

@@ -43,6 +43,7 @@
 import io.quarkus.deployment.util.ServiceUtil;
 import io.quarkus.deployment.util.WebJarUtil;
 import io.quarkus.runtime.LaunchMode;
+import io.quarkus.runtime.RuntimeValue;
 import io.quarkus.runtime.metrics.MetricsFactory;
 import io.quarkus.smallrye.graphql.runtime.SmallRyeGraphQLRecorder;
 import io.quarkus.smallrye.graphql.runtime.SmallRyeGraphQLRuntimeConfig;
@@ -51,7 +52,6 @@
 import io.quarkus.vertx.http.deployment.RequireBodyHandlerBuildItem;
 import io.quarkus.vertx.http.deployment.RouteBuildItem;
 import io.quarkus.vertx.http.deployment.devmode.NotFoundPageDisplayableEndpointBuildItem;
-import io.quarkus.vertx.http.runtime.HandlerType;
 import io.smallrye.graphql.cdi.config.ConfigKey;
 import io.smallrye.graphql.cdi.config.GraphQLConfig;
 import io.smallrye.graphql.cdi.producer.GraphQLProducer;
@@ -145,6 +145,7 @@ void registerNativeImageResources(BuildProducer<ServiceProviderBuildItem> servic
     void buildExecutionService(
             BuildProducer<ReflectiveClassBuildItem> reflectiveClassProducer,
             BuildProducer<ReflectiveHierarchyBuildItem> reflectiveHierarchyProducer,
+            BuildProducer<SmallRyeGraphQLInitializedBuildItem> graphQLInitializedProducer,
             SmallRyeGraphQLRecorder recorder,
             BeanContainerBuildItem beanContainer,
             CombinedIndexBuildItem combinedIndex,
@@ -154,7 +155,8 @@ void buildExecutionService(
 
         Schema schema = SchemaBuilder.build(index, graphQLConfig.autoNameStrategy);
 
-        recorder.createExecutionService(beanContainer.getValue(), schema);
+        RuntimeValue<Boolean> initialized = recorder.createExecutionService(beanContainer.getValue(), schema);
+        graphQLInitializedProducer.produce(new SmallRyeGraphQLInitializedBuildItem(initialized));
 
         // Make sure the complex object from the application can work in native mode
         reflectiveClassProducer.produce(new ReflectiveClassBuildItem(true, true, getSchemaJavaClasses(schema)));
@@ -173,19 +175,26 @@ void requireBody(BuildProducer<RequireBodyHandlerBuildItem> requireBodyHandlerPr
     @BuildStep
     void buildSchemaEndpoint(
             BuildProducer<RouteBuildItem> routeProducer,
+            SmallRyeGraphQLInitializedBuildItem graphQLInitializedBuildItem,
             SmallRyeGraphQLRecorder recorder,
             SmallRyeGraphQLConfig graphQLConfig) {
 
-        Handler<RoutingContext> schemaHandler = recorder.schemaHandler();
-        routeProducer.produce(
-                new RouteBuildItem(graphQLConfig.rootPath + SCHEMA_PATH, schemaHandler, HandlerType.BLOCKING));
+        Handler<RoutingContext> schemaHandler = recorder.schemaHandler(graphQLInitializedBuildItem.getInitialized());
+
+        routeProducer.produce(new RouteBuildItem.Builder()
+                .route(graphQLConfig.rootPath + SCHEMA_PATH)
+                .handler(schemaHandler)
+                .blockingRoute()
+                .build());
+
     }
 
     @Record(ExecutionTime.STATIC_INIT)
     @BuildStep
     void buildExecutionEndpoint(
             BuildProducer<RouteBuildItem> routeProducer,
             BuildProducer<NotFoundPageDisplayableEndpointBuildItem> notFoundPageDisplayableEndpointProducer,
+            SmallRyeGraphQLInitializedBuildItem graphQLInitializedBuildItem,
             SmallRyeGraphQLRecorder recorder,
             ShutdownContextBuildItem shutdownContext,
             LaunchModeBuildItem launchMode,
@@ -217,7 +226,8 @@ void buildExecutionEndpoint(
 
         Boolean allowGet = ConfigProvider.getConfig().getOptionalValue(ConfigKey.ALLOW_GET, boolean.class).orElse(false);
 
-        Handler<RoutingContext> executionHandler = recorder.executionHandler(allowGet);
+        Handler<RoutingContext> executionHandler = recorder.executionHandler(graphQLInitializedBuildItem.getInitialized(),
+                allowGet);
         routeProducer.produce(new RouteBuildItem.Builder()
                 .route(graphQLConfig.rootPath)
                 .handler(executionHandler)

extensions/smallrye-graphql/runtime/src/main/java/io/quarkus/smallrye/graphql/runtime/SmallRyeGraphQLNoEndpointHandler.java

@@ -0,0 +1,21 @@
+package io.quarkus.smallrye.graphql.runtime;
+
+import io.vertx.core.Handler;
+import io.vertx.core.http.HttpHeaders;
+import io.vertx.core.http.HttpServerResponse;
+import io.vertx.ext.web.RoutingContext;
+
+/**
+ * Handler that is used when no endpoint is available
+ */
+public class SmallRyeGraphQLNoEndpointHandler implements Handler<RoutingContext> {
+    private static final String CONTENT_TYPE = "text/plain; charset=UTF-8";
+    private static final String MESSAGE = "GraphQL Schema not generated. Make sure you have a GraphQL Endpoint. Go to https://quarkus.io/guides/microprofile-graphql to learn how";
+
+    @Override
+    public void handle(RoutingContext event) {
+        HttpServerResponse response = event.response();
+        response.headers().set(HttpHeaders.CONTENT_TYPE, CONTENT_TYPE);
+        response.setStatusCode(404).end(MESSAGE);
+    }
+}

extensions/smallrye-graphql/runtime/src/main/java/io/quarkus/smallrye/graphql/runtime/SmallRyeGraphQLRecorder.java

@@ -3,7 +3,9 @@
 import javax.enterprise.inject.Instance;
 import javax.enterprise.inject.spi.CDI;
 
+import graphql.schema.GraphQLSchema;
 import io.quarkus.arc.runtime.BeanContainer;
+import io.quarkus.runtime.RuntimeValue;
 import io.quarkus.runtime.ShutdownContext;
 import io.quarkus.runtime.annotations.Recorder;
 import io.quarkus.security.identity.CurrentIdentityAssociation;
@@ -18,27 +20,36 @@
 @Recorder
 public class SmallRyeGraphQLRecorder {
 
-    public void createExecutionService(BeanContainer beanContainer, Schema schema) {
+    public RuntimeValue<Boolean> createExecutionService(BeanContainer beanContainer, Schema schema) {
         GraphQLProducer graphQLProducer = beanContainer.instance(GraphQLProducer.class);
         GraphQLConfig graphQLConfig = beanContainer.instance(GraphQLConfig.class);
-        graphQLProducer.initialize(schema, graphQLConfig);
+        GraphQLSchema graphQLSchema = graphQLProducer.initialize(schema, graphQLConfig);
+        return new RuntimeValue<>(graphQLSchema != null);
     }
 
-    public Handler<RoutingContext> executionHandler(boolean allowGet) {
-        Instance<CurrentIdentityAssociation> identityAssociations = CDI.current()
-                .select(CurrentIdentityAssociation.class);
-        CurrentIdentityAssociation association;
-        if (identityAssociations.isResolvable()) {
-            association = identityAssociations.get();
+    public Handler<RoutingContext> executionHandler(RuntimeValue<Boolean> initialized, boolean allowGet) {
+        if (initialized.getValue()) {
+            Instance<CurrentIdentityAssociation> identityAssociations = CDI.current()
+                    .select(CurrentIdentityAssociation.class);
+            CurrentIdentityAssociation association;
+            if (identityAssociations.isResolvable()) {
+                association = identityAssociations.get();
+            } else {
+                association = null;
+            }
+            CurrentVertxRequest currentVertxRequest = CDI.current().select(CurrentVertxRequest.class).get();
+            return new SmallRyeGraphQLExecutionHandler(allowGet, association, currentVertxRequest);
         } else {
-            association = null;
+            return new SmallRyeGraphQLNoEndpointHandler();
         }
-        CurrentVertxRequest currentVertxRequest = CDI.current().select(CurrentVertxRequest.class).get();
-        return new SmallRyeGraphQLExecutionHandler(allowGet, association, currentVertxRequest);
     }
 
-    public Handler<RoutingContext> schemaHandler() {
-        return new SmallRyeGraphQLSchemaHandler();
+    public Handler<RoutingContext> schemaHandler(RuntimeValue<Boolean> initialized) {
+        if (initialized.getValue()) {
+            return new SmallRyeGraphQLSchemaHandler();
+        } else {
+            return new SmallRyeGraphQLNoEndpointHandler();
+        }
     }
 
     public Handler<RoutingContext> uiHandler(String graphqlUiFinalDestination,