Record noteworthy build items into extension metadata

core/builder/src/main/java/io/quarkus/builder/item/AddToMetadata.java

@@ -0,0 +1,5 @@
+package io.quarkus.builder.item;
+
+public @interface AddToMetadata {
+    String value();
+}

core/deployment/src/main/java/io/quarkus/deployment/ExtensionLoader.java

@@ -50,6 +50,7 @@
 import org.jboss.logging.Logger;
 import org.wildfly.common.function.Functions;
 
+import io.quarkus.bootstrap.BootstrapConstants;
 import io.quarkus.bootstrap.model.ApplicationModel;
 import io.quarkus.builder.BuildChainBuilder;
 import io.quarkus.builder.BuildContext;
@@ -157,7 +158,7 @@ public String getId() {
 
         // the proxy objects used for run time config in the recorders
         Map<Class<?>, Object> proxies = new HashMap<>();
-        for (Class<?> clazz : ServiceUtil.classesNamedIn(classLoader, "META-INF/quarkus-build-steps.list")) {
+        for (Class<?> clazz : ServiceUtil.classesNamedIn(classLoader, BootstrapConstants.BUILD_STEPS_PATH)) {
             try {
                 result = result.andThen(ExtensionLoader.loadStepsFromClass(clazz, readResult, proxies, bsf));
             } catch (Throwable e) {

core/deployment/src/main/java/io/quarkus/deployment/builditem/DevServicesResultBuildItem.java

@@ -6,6 +6,7 @@
 import java.util.HashMap;
 import java.util.Map;
 
+import io.quarkus.builder.item.AddToMetadata;
 import io.quarkus.builder.item.MultiBuildItem;
 
 /**
@@ -17,6 +18,7 @@
  *
  * {@link RunningDevService} helps to manage the lifecycle of the running dev service.
  */
+@AddToMetadata("dev-service")
 public final class DevServicesResultBuildItem extends MultiBuildItem {
 
     private final String name;

core/deployment/src/main/java/io/quarkus/deployment/pkg/steps/JarResultBuildStep.java

@@ -1,6 +1,8 @@
 package io.quarkus.deployment.pkg.steps;
 
-import static io.quarkus.deployment.pkg.PackageConfig.JarConfig.JarType.*;
+import static io.quarkus.deployment.pkg.PackageConfig.JarConfig.JarType.LEGACY_JAR;
+import static io.quarkus.deployment.pkg.PackageConfig.JarConfig.JarType.MUTABLE_JAR;
+import static io.quarkus.deployment.pkg.PackageConfig.JarConfig.JarType.UBER_JAR;
 
 import java.io.BufferedInputStream;
 import java.io.BufferedWriter;
@@ -1474,6 +1476,7 @@ private static class IsEntryIgnoredForUberJarPredicate implements Predicate<Stri
                 "META-INF/DEPENDENCIES.txt",
                 "META-INF/beans.xml",
                 "META-INF/quarkus-config-roots.list",
+                "META-INF/noteworthy-build-items.list",
                 "META-INF/quarkus-javadoc.properties",
                 "META-INF/quarkus-extension.properties",
                 "META-INF/quarkus-extension.json",

core/processor/src/main/java/io/quarkus/annotation/processor/Constants.java

@@ -70,6 +70,8 @@ final public class Constants {
     public static final String ANNOTATION_CONFIG_WITH_DEFAULT = "io.smallrye.config.WithDefault";
     public static final String ANNOTATION_CONFIG_WITH_UNNAMED_KEY = "io.smallrye.config.WithUnnamedKey";
 
+    public static final String ANNOTATION_ADD_BUILD_ITEM_TO_METADATA = "io.quarkus.builder.item.AddToMetadata";
+
     public static final Set<String> SUPPORTED_ANNOTATIONS_TYPES = Set.of(ANNOTATION_BUILD_STEP, ANNOTATION_CONFIG_GROUP,
             ANNOTATION_CONFIG_ROOT, ANNOTATION_RECORDER, ANNOTATION_CONFIG_MAPPING);
 

core/processor/src/main/java/io/quarkus/annotation/processor/ExtensionAnnotationProcessor.java

@@ -1,5 +1,6 @@
 package io.quarkus.annotation.processor;
 
+import static io.quarkus.annotation.processor.Constants.ANNOTATION_ADD_BUILD_ITEM_TO_METADATA;
 import static io.quarkus.annotation.processor.Constants.ANNOTATION_CONFIG_GROUP;
 import static io.quarkus.annotation.processor.Constants.ANNOTATION_CONFIG_MAPPING;
 import static javax.lang.model.util.ElementFilter.constructorsIn;
@@ -54,6 +55,7 @@
 import javax.lang.model.type.PrimitiveType;
 import javax.lang.model.type.TypeKind;
 import javax.lang.model.type.TypeMirror;
+import javax.lang.model.util.Types;
 import javax.tools.Diagnostic;
 import javax.tools.FileObject;
 import javax.tools.StandardLocation;
@@ -82,11 +84,13 @@ public class ExtensionAnnotationProcessor extends AbstractProcessor {
 
     private static final Pattern REMOVE_LEADING_SPACE = Pattern.compile("^ ", Pattern.MULTILINE);
     private static final String QUARKUS_GENERATED = "io.quarkus.Generated";
+    public static final String META_INF_NOTEWORTHY_BUILD_ITEMS_LIST = "META-INF/noteworthy-build-items.list";
 
     private final ConfigDocWriter configDocWriter = new ConfigDocWriter();
     private final ConfigDocItemScanner configDocItemScanner = new ConfigDocItemScanner();
     private final Set<String> generatedAccessors = new ConcurrentHashMap<String, Boolean>().keySet(Boolean.TRUE);
     private final Set<String> generatedJavaDocs = new ConcurrentHashMap<String, Boolean>().keySet(Boolean.TRUE);
+    private final Set<String> noteworthyBuildItems = new ConcurrentHashMap<String, Boolean>().keySet(Boolean.TRUE);
     private final boolean generateDocs = !(Boolean.getBoolean("skipDocs") || Boolean.getBoolean("quickly"));
 
     private final Map<String, Boolean> ANNOTATION_USAGE_TRACKER = new ConcurrentHashMap<>();
@@ -270,6 +274,21 @@ public FileVisitResult postVisitDirectory(final Path dir, final IOException exc)
             }
         }
 
+        if (!noteworthyBuildItems.isEmpty()) {
+            try {
+                final FileObject noteworthies = filer.createResource(StandardLocation.CLASS_OUTPUT, Constants.EMPTY,
+                        META_INF_NOTEWORTHY_BUILD_ITEMS_LIST);
+                Writer writer = noteworthies.openWriter();
+                for (String o : noteworthyBuildItems) {
+                    writer.append(o);
+                    writer.append("\n");
+                }
+                writer.close();
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
+
         try {
             if (generateDocs) {
                 final Set<ConfigDocGeneratedOutput> outputs = configDocItemScanner
@@ -357,6 +376,7 @@ private void processBuildStep(RoundEnvironment roundEnv, TypeElement annotation)
                     .toString();
             if (processorClassNames.add(binaryName)) {
                 validateRecordBuildSteps(clazz);
+                recordNoteworthyBuildItems(clazz);
                 recordConfigJavadoc(clazz);
                 generateAccessor(clazz);
                 final StringBuilder rbn = getRelativeBinaryName(clazz, new StringBuilder());
@@ -433,6 +453,64 @@ private void validateRecordBuildSteps(TypeElement clazz) {
         }
     }
 
+    private void recordNoteworthyBuildItems(TypeElement clazz) {
+        for (Element e : clazz.getEnclosedElements()) {
+            if (e.getKind() != ElementKind.METHOD) {
+                continue;
+            }
+            ExecutableElement ex = (ExecutableElement) e;
+            if (!isAnnotationPresent(ex, Constants.ANNOTATION_BUILD_STEP)) {
+                continue;
+            }
+
+            if (!(e instanceof ExecutableElement)) {
+                continue;
+            }
+
+            ExecutableElement exel = (ExecutableElement) e;
+
+            TypeMirror returned = exel.getReturnType();
+            if (returned.getKind() != TypeKind.VOID) {
+                Types typeUtils = processingEnv.getTypeUtils();
+
+                List<? extends AnnotationMirror> allAnnotations = typeUtils.asElement(returned)
+                        .getAnnotationMirrors();
+                Optional<? extends AnnotationMirror> oam = allAnnotations.stream()
+                        .filter(this::isAddMetadataAnnotation)
+                        .findAny();
+                if (oam.isPresent()) {
+                    AnnotationMirror am = oam.get();
+
+                    Map<? extends ExecutableElement, ? extends AnnotationValue> elementValues = am.getElementValues();
+                    Optional<? extends Map.Entry<? extends ExecutableElement, ? extends AnnotationValue>> valueEntry = elementValues
+                            .entrySet()
+                            .stream()
+                            .filter(entry -> entry.getKey()
+                                    .getSimpleName()
+                                    .toString()
+                                    .equals("value"))
+                            .findAny();
+                    if (valueEntry.isPresent()) {
+                        String value = valueEntry.get()
+                                .getValue()
+                                .getValue()// First getValue gets  from the entry, the second gets from the annotation
+                                .toString();
+                        noteworthyBuildItems.add(value);
+                    }
+
+                }
+            }
+        }
+    }
+
+    private boolean isAddMetadataAnnotation(AnnotationMirror meth) {
+        Types typeUtils = processingEnv.getTypeUtils();
+        TypeElement element = (TypeElement) typeUtils.asElement(meth.getAnnotationType());
+        String name = element.getQualifiedName()
+                .toString();
+        return ANNOTATION_ADD_BUILD_ITEM_TO_METADATA.equals(name);
+    }
+
     private Name getPackageName(TypeElement clazz) {
         return processingEnv.getElementUtils()
                 .getPackageOf(clazz)

core/processor/src/test/java/io/quarkus/annotation/processor/ExtensionAnnotationProcessorTest.java

@@ -2,6 +2,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -54,9 +55,36 @@ void shouldGenerateABscFile(Results results) throws IOException {
         assertEquals("org.acme.examples.ClassWithBuildStep", contents);
     }
 
-    private String removeLineBreaks(String s) {
-        return s.replace(System.getProperty("line.separator"), "")
-                .replace("\n", "");
+    @Test
+    @Classpath("org.acme.examples.ClassWithBuildStep")
+    void shouldNotGenerateANoteworthyBuildItemsFileIfThereAreNoAnnotationsForIt(Results results) throws IOException {
+        assertNoErrrors(results);
+        List<JavaFileObject> sources = results.sources;
+        JavaFileObject buildItemsFile = sources.stream()
+                .filter(source -> source.getName()
+                        .endsWith("build-items.list"))
+                .findAny()
+                .orElse(null);
+        assertNull(buildItemsFile);
+
+    }
+
+    @Test
+    @Classpath("org.acme.examples.ClassWithNoteworthyBuildItem")
+    void shouldGenerateANoteworthyBuildItemsFile(Results results) throws IOException {
+        assertNoErrrors(results);
+        List<JavaFileObject> sources = results.sources;
+        JavaFileObject buildItemsFile = sources.stream()
+                .filter(source -> source.getName()
+                        .endsWith("build-items.list"))
+                .findAny()
+                .orElse(null);
+        assertNotNull(buildItemsFile);
+
+        String contents = removeLineBreaks(new String(buildItemsFile
+                .openInputStream()
+                .readAllBytes(), StandardCharsets.UTF_8));
+        assertEquals("some-cool-ability", contents);
     }
 
     @Test
@@ -65,6 +93,11 @@ void shouldProcessEmptyClassWithoutErrors(Results results) {
         assertNoErrrors(results);
     }
 
+    private String removeLineBreaks(String s) {
+        return s.replace(System.getProperty("line.separator"), "")
+                .replace("\n", "");
+    }
+
     private static void assertNoErrrors(Results results) {
         assertEquals(0, results.find()
                 .errors()

core/processor/src/test/resources/org/acme/examples/ClassWithNoteworthyBuildItem.java

@@ -0,0 +1,21 @@
+package org.acme.examples;
+
+import io.quarkus.deployment.annotations.BuildStep;
+
+public class ClassWithNoteworthyBuildItem {
+    @BuildStep
+    NoteworthyBuildItem devService() {
+        return new NoteworthyBuildItem();
+    }
+
+    // This one shouldn't get recorded for use in the metadata
+    @BuildStep
+    ArbitraryBuildItem arbitrary() {
+        return new ArbitraryBuildItem();
+    }
+
+    // This one shouldn't get recorded, obviously, and it should not cause runtime exceptions
+    @BuildStep
+    void boring() {
+    }
+}

core/processor/src/test/resources/org/acme/examples/NoteworthyBuildItem.java

@@ -0,0 +1,9 @@
+package org.acme.examples;
+
+import io.quarkus.builder.item.AddToMetadata;
+import io.quarkus.builder.item.MultiBuildItem;
+
+@AddToMetadata("some-cool-ability")
+public final class NoteworthyBuildItem extends MultiBuildItem {
+
+}

docs/src/main/asciidoc/extension-metadata.adoc

@@ -178,6 +178,11 @@
 Same as `quarkus-config-roots.list`, this file may appear in a runtime extension artifact as well in a deployment one. It is generated as part of the extension project build process from the descriptions of configuration options available in the classes annotated with `io.quarkus.runtime.annotations.ConfigRoot` and is not supported to be edited manually.
 
 [[quarkus-build-steps]]
 == META-INF/quarkus-build-steps.list
 
 This file may appear in a deployment extension artifact. It contains a list of classes that implement Quarkus build steps (methods annotated with `io.quarkus.deployment.annotations.BuildStep`). This file is generated as part of the extension project build process and must not be edited manually.
+
+[[quarkus-build-steps]]
+== META-INF/noteworthy-build-items.list
+
+This file may appear in a deployment extension artifact. It contains a list of build items produced by this extension that represent noteworthy function which should be noted in the extension metadata.

independent-projects/bootstrap/app-model/src/main/java/io/quarkus/bootstrap/BootstrapConstants.java

@@ -29,6 +29,7 @@ public interface BootstrapConstants {
 
     String DESCRIPTOR_PATH = META_INF + '/' + DESCRIPTOR_FILE_NAME;
     String BUILD_STEPS_PATH = META_INF + "/quarkus-build-steps.list";
+    String NOTEWORTHY_BUILD_ITEMS_PATH = META_INF + "/noteworthy-build-items.list";
     String EXTENSION_METADATA_PATH = META_INF + '/' + QUARKUS_EXTENSION_FILE_NAME;
 
     String PROP_DEPLOYMENT_ARTIFACT = "deployment-artifact";

independent-projects/extension-maven-plugin/src/main/java/io/quarkus/maven/ExtensionDescriptorMojo.java

@@ -18,12 +18,15 @@
 import java.util.Properties;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import org.apache.maven.artifact.Artifact;
 import org.apache.maven.execution.MavenSession;
 import org.apache.maven.model.Scm;
 import org.apache.maven.plugin.AbstractMojo;
 import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
 import org.apache.maven.plugin.logging.Log;
 import org.apache.maven.plugins.annotations.Component;
 import org.apache.maven.plugins.annotations.LifecyclePhase;
@@ -82,7 +85,7 @@
  * Generates Quarkus extension descriptor for the runtime artifact.
  * <p>
  * <p/>
- * Also generates META-INF/quarkus-extension.json which includes properties of
+ * Also generates META-INF/quarkus-extension.yaml which includes properties of
  * the extension such as name, labels, maven coordinates, etc that are used by
  * the tools.
  *
@@ -459,6 +462,7 @@ public void execute() throws MojoExecutionException {
 
         setBuiltWithQuarkusCoreVersion(extObject);
         addJavaVersion(extObject);
+        addNoteworthyItems(extObject);
         addCapabilities(extObject);
         addSource(extObject);
         addExtensionDependencies(extObject);
@@ -739,6 +743,29 @@ public void addJavaVersion(ObjectNode extObject) {
         }
     }
 
+    private void addNoteworthyItems(ObjectNode extObject) {
+        try {
+            Set<String> noteworthies = getNoteworthyList();
+            if (noteworthies != null) {
+                for (String noteworthy : noteworthies) {
+                    ObjectNode metadataNode = getMetadataNode(extObject);
+                    // Ignore if already set
+                    String key = "provides-" + noteworthy;
+                    if (!metadataNode.has(key) && noteworthy != null) {
+                        metadataNode.put(key, "true");
+                    }
+                }
+
+            }
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        } catch (MojoExecutionException e) {
+            throw new RuntimeException(e);
+        } catch (MojoFailureException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     private void addCapabilities(ObjectNode extObject) throws MojoExecutionException {
         ObjectNode capsNode = null;
         if (!capabilities.getProvides().isEmpty()) {
@@ -1014,6 +1041,35 @@ private org.eclipse.aether.artifact.Artifact getDeploymentArtifact(org.eclipse.a
         return DependencyUtils.toArtifact(deploymentStr);
     }
 
+    private Set<String> getNoteworthyList() throws IOException, MojoExecutionException, MojoFailureException {
+
+        ArtifactCoords deploymentCoords = getDeploymentCoords();
+
+        // Ask Maven to resolve the artifact's location, so we can look inside it.
+        // That could be downloading it from a remote repository, searching the local repository or a cache.
+
+        String artifactId = deploymentCoords.getArtifactId();
+        org.eclipse.aether.artifact.Artifact aetherArtifact = new DefaultArtifact(
+                deploymentCoords.getGroupId(),
+                artifactId,
+                deploymentCoords.getClassifier(),
+                deploymentCoords.getType(),
+                deploymentCoords.getVersion());
+
+        final LocalProject localProject = workspaceProvider.getProject(deploymentCoords.getGroupId(),
+                deploymentCoords.getArtifactId());
+        if (localProject != null) {
+            Path file = localProject.getClassesDir().resolve(BootstrapConstants.NOTEWORTHY_BUILD_ITEMS_PATH);
+            if (Files.exists(file)) {
+                try (Stream<String> lines = Files.lines(file)) {
+                    return lines.collect(Collectors.toSet());
+                }
+            }
+        }
+
+        return null;
+    }
+
     private Properties getExtensionDescriptor(org.eclipse.aether.artifact.Artifact a, boolean packaged) {
         final File f;
         try {