4.x: Use Helidon metadata format (HSON) for service registry generated file.

all/pom.xml

@@ -1090,6 +1090,10 @@
             <groupId>io.helidon.inject.configdriven</groupId>
             <artifactId>helidon-inject-configdriven-processor</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.helidon.service</groupId>
+            <artifactId>helidon-service-metadata</artifactId>
+        </dependency>
         <dependency>
             <groupId>io.helidon.service</groupId>
             <artifactId>helidon-service-registry</artifactId>

bom/pom.xml

@@ -1436,6 +1436,11 @@
             </dependency>
 
             <!-- Service registry -->
+            <dependency>
+                <groupId>io.helidon.service</groupId>
+                <artifactId>helidon-service-metadata</artifactId>
+                <version>${helidon.version}</version>
+            </dependency>
             <dependency>
                 <groupId>io.helidon.service</groupId>
                 <artifactId>helidon-service-registry</artifactId>

codegen/apt/src/main/java/io/helidon/codegen/apt/AptFiler.java

@@ -17,6 +17,7 @@
 package io.helidon.codegen.apt;
 
 import java.io.BufferedReader;
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
@@ -35,6 +36,7 @@
 import io.helidon.codegen.CodegenException;
 import io.helidon.codegen.CodegenFiler;
 import io.helidon.codegen.CodegenOptions;
+import io.helidon.codegen.FilerResource;
 import io.helidon.codegen.FilerTextResource;
 import io.helidon.codegen.IndentType;
 import io.helidon.codegen.classmodel.ClassModel;
@@ -107,6 +109,20 @@ public FilerTextResource textResource(String location, Object... originatingElem
         }
     }
 
+    @Override
+    public FilerResource resource(String location, Object... originatingElements) {
+        try {
+            var resource = filer.getResource(StandardLocation.CLASS_OUTPUT, "", location);
+            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            try (var is = resource.openInputStream()) {
+                is.transferTo(baos);
+            }
+            return new FilerResourceImpl(filer, location, toElements(originatingElements), resource, baos.toByteArray());
+        } catch (IOException e) {
+            return new FilerResourceImpl(filer, location, toElements(originatingElements));
+        }
+    }
+
     private Object originatingElement(Element[] elements, Object alternative) {
         if (elements.length == 0) {
             return alternative;

codegen/apt/src/main/java/io/helidon/codegen/apt/FilerResourceImpl.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2024 Oracle and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.helidon.codegen.apt;
+
+import java.util.Arrays;
+
+import javax.annotation.processing.Filer;
+import javax.lang.model.element.Element;
+import javax.tools.FileObject;
+import javax.tools.StandardLocation;
+
+import io.helidon.codegen.CodegenException;
+import io.helidon.codegen.FilerResource;
+
+class FilerResourceImpl implements FilerResource {
+    private final Filer filer;
+    private final String location;
+    private final Element[] originatingElements;
+    private final FileObject originalResource; // may be null
+
+    private byte[] currentBytes;
+
+    private boolean modified;
+
+    FilerResourceImpl(Filer filer, String location, Element[] originatingElements) {
+        this.filer = filer;
+        this.location = location;
+        this.originatingElements = originatingElements;
+        this.originalResource = null;
+        this.currentBytes = new byte[0];
+    }
+
+    FilerResourceImpl(Filer filer,
+                      String location,
+                      Element[] originatingElements,
+                      FileObject originalResource,
+                      byte[] existingBytes) {
+        this.filer = filer;
+        this.location = location;
+        this.originatingElements = originatingElements;
+        this.originalResource = originalResource;
+        this.currentBytes = existingBytes;
+    }
+
+    @Override
+    public byte[] bytes() {
+        return Arrays.copyOf(currentBytes, currentBytes.length);
+    }
+
+    @Override
+    public void bytes(byte[] newBytes) {
+        currentBytes = Arrays.copyOf(newBytes, newBytes.length);
+        modified = true;
+    }
+
+    @Override
+    public void write() {
+        if (modified) {
+            if (originalResource != null) {
+                originalResource.delete();
+            }
+            try {
+                FileObject newResource = filer.createResource(StandardLocation.CLASS_OUTPUT,
+                                                              "",
+                                                              location,
+                                                              originatingElements);
+                try (var os = newResource.openOutputStream()) {
+                    os.write(currentBytes);
+                }
+            } catch (Exception e) {
+                throw new CodegenException("Failed to create resource: " + location, e);
+            }
+        }
+    }
+}

codegen/codegen/src/main/java/io/helidon/codegen/CodegenFiler.java

@@ -64,6 +64,18 @@ default FilerTextResource textResource(String location, Object... originatingEle
         throw new UnsupportedOperationException("Method textResource not implemented yet on " + getClass().getName());
     }
 
+    /**
+     * A text resource that can be updated in the output.
+     * Note that the resource can only be written once per processing round.
+     *
+     * @param location            location to read/write to in the classes output directory
+     * @param originatingElements elements that caused this file to be generated
+     * @return the resource that can be used to update the file
+     */
+    default FilerResource resource(String location, Object... originatingElements) {
+        throw new UnsupportedOperationException("Method resource not implemented yet on " + getClass().getName());
+    }
+
     /**
      * Write a {@code META-INF/services} file for a specific provider interface and implementation(s).
      *

codegen/codegen/src/main/java/io/helidon/codegen/FilerResource.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2024 Oracle and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.helidon.codegen;
+
+/**
+ * A resource from output (such as {@code target/META-INF/helidon}) that can have existing
+ * values, and may be replaced with a new value.
+ */
+public interface FilerResource {
+    /**
+     * Existing bytes of the resource. Returns empty array, if the resource does not exist or is empty.
+     *
+     * @return bytes of the resource
+     */
+    byte[] bytes();
+
+    /**
+     * New bytes of the resource.
+     *
+     * @param newBytes new bytes to {@link #write()} to the resource file
+     */
+    void bytes(byte[] newBytes);
+
+    /**
+     * Writes the new bytes to the output. This operation can only be called once per codegen round.
+     */
+    void write();
+}

integrations/graal/native-image-extension/src/main/java/io/helidon/integrations/graal/nativeimage/extension/HelidonReflectionFeature.java

@@ -35,7 +35,7 @@
 import io.helidon.common.features.HelidonFeatures;
 import io.helidon.common.types.TypeName;
 import io.helidon.logging.common.LogConfig;
-import io.helidon.service.registry.DescriptorMetadata;
+import io.helidon.service.registry.DescriptorHandler;
 import io.helidon.service.registry.ServiceDiscovery;
 import io.helidon.service.registry.ServiceLoader__ServiceDescriptor;
 import io.helidon.service.registry.ServiceRegistryConfig;
@@ -190,7 +190,7 @@ private void processServiceDescriptors(BeforeAnalysisContext context) {
 
         sd.allMetadata()
                 .stream()
-                .map(DescriptorMetadata::descriptor)
+                .map(DescriptorHandler::descriptor)
                 .filter(it -> it instanceof ServiceLoader__ServiceDescriptor)
                 .map(it -> (ServiceLoader__ServiceDescriptor) it)
                 .map(ServiceLoader__ServiceDescriptor::serviceType)

service/README.md

@@ -98,14 +98,39 @@ reflection (the class, and the field).
 
 ### Registry file format
 
-The service registry uses a `service.registry` in `META-INF/helidon` directory to store the main metadata of
+The service registry uses a `service-registry.json` file in `META-INF/helidon` directory to store the main metadata of
 the service. This is to allow proper ordering of services (Service weight is one of the information stored) and
 lazy loading of services (which is the approach chosen in the core service registry).
 
-The format is as follows:
-
-```
-registry-type:service-descriptor-type:weight(double):contracts(comma separated)
+The format is as follows (using `//` to comment sections, not part of the format):
+
+```json
+// root is an array of modules (we always generate a single module, but this allows a combined array, i.e. when using shading
+[
+  {
+    // version of the metadata file, defaults to 1 (and will always default to 1)
+    "version": 1,
+    // name of the module
+    "module": "io.helidon.example",
+    // all services in this module
+    "services": [
+      {
+        // version of the service descriptor, defaults to 1 (and will always default to 1)
+        "version": 1,
+        // core (Service registry) or inject (Service Injection), defaults to core
+        "type": "inject",
+        // weight, defaults to 100
+        "weight": 91.4,
+        // class of the service descriptor - generated type that contains public constant INSTANCE
+        "descriptor": "io.helidon.example.ServiceImpl__ServiceDescriptor",
+        // all contracts this service implements
+        "contracts": [
+          "io.helidon.example.ServiceApi"
+        ]
+      }
+    ]
+  }
+]
 ```
 
 Example:

service/codegen/pom.xml

@@ -51,5 +51,13 @@
             <groupId>io.helidon.codegen</groupId>
             <artifactId>helidon-codegen-class-model</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.helidon.metadata</groupId>
+            <artifactId>helidon-metadata-hson</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.service</groupId>
+            <artifactId>helidon-service-metadata</artifactId>
+        </dependency>
     </dependencies>
 </project>