feat(generator): template generator Maven plugin (#1106)

* feat(generator): add Maven plugin to generate templates

* set maven plugin plugin version

* Make output directory configurable

connector-sdk/element-template-generator-maven-plugin/README.md

@@ -0,0 +1,57 @@
+# Element Template Generator Maven Plugin
+
+This plugin generates [Connector Templates](https://docs.camunda.io/docs/components/connectors/custom-built-connectors/connector-templates/)
+based on Connector code.
+
+To use the plugin, your Connector must be annotated with `@ElementTemplate` annotation.
+See the [Element Template Generator](../element-template-generator) module for more information.
+
+## Usage
+
+Add the following plugin to your `pom.xml`:
+
+```xml
+<plugin>
+  <groupId>io.camunda.connector</groupId>
+  <artifactId>element-template-generator-maven-plugin</artifactId>
+  <version>${version}</version>
+  <executions>
+    <execution>
+      <goals>
+        <goal>generate-templates</goal>
+      </goals>
+    </execution>
+  </executions>
+  <configuration>
+    <connectorClasses>
+      <connectorClass>io.camunda.connector.MyConnector</connectorClass>
+    </connectorClasses>
+  </configuration>
+</plugin>
+```
+
+Edit the `connectorClass` element to point to your Connector class. You can specify multiple
+classes if you have more than one Connector in one project.
+
+By default, the generated element template will be placed in `element-templates` directory inside
+your project's base directory. You can change the output directory by setting the `outputDirectory`
+configuration parameter.
+
+## Accessing classes from other modules
+
+If your Connector definition references classes from other modules, the plugin will not be able
+to find them automatically. You can add direct dependencies of your project to the plugin classpath
+by adding the following configuration to the plugin:
+
+```xml
+<configuration>
+  <connectorClasses>
+    <connectorClass>io.camunda.connector.MyConnector</connectorClass>
+  </connectorClasses>
+  <includeDependencies>
+    <includeDependency>io.camunda.connector:my-connector-library</includeDependency>
+  </includeDependencies>
+</configuration>
+```
+
+Note that the plugin will not resolve transitive dependencies of the specified dependencies.

connector-sdk/element-template-generator-maven-plugin/pom.xml

@@ -0,0 +1,63 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <parent>
+    <groupId>io.camunda.connector</groupId>
+    <artifactId>connector-parent</artifactId>
+    <relativePath>../../parent/pom.xml</relativePath>
+    <version>0.23.0-SNAPSHOT</version>
+  </parent>
+
+  <name>element-template-generator-maven-plugin</name>
+  <description>Maven plugin for generating connector templates</description>
+  <artifactId>element-template-generator-maven-plugin</artifactId>
+  <packaging>maven-plugin</packaging>
+
+  <properties>
+    <version.maven-plugin-api>3.9.4</version.maven-plugin-api>
+    <version.maven-plugin-annotations>3.9.0</version.maven-plugin-annotations>
+    <version.maven-plugin-plugin>3.9.0</version.maven-plugin-plugin>
+    <version.maven-project>2.2.1</version.maven-project>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>io.camunda.connector</groupId>
+      <artifactId>element-template-generator</artifactId>
+    </dependency>
+
+    <dependency>
+      <groupId>org.apache.maven</groupId>
+      <artifactId>maven-plugin-api</artifactId>
+      <version>${version.maven-plugin-api}</version>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.maven.plugin-tools</groupId>
+      <artifactId>maven-plugin-annotations</artifactId>
+      <version>${version.maven-plugin-annotations}</version>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.maven</groupId>
+      <artifactId>maven-project</artifactId>
+      <version>${version.maven-project}</version>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-plugin-plugin</artifactId>
+        <version>${version.maven-plugin-plugin}</version>
+        <executions>
+          <execution>
+            <id>default-descriptor</id>
+            <phase>process-classes</phase>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

connector-sdk/element-template-generator-maven-plugin/src/main/java/io/camunda/connector/generator/ElementTemplateGeneratorMojo.java

@@ -0,0 +1,130 @@
+/*
+ * Copyright Camunda Services GmbH and/or licensed to Camunda Services GmbH
+ * under one or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information regarding copyright
+ * ownership. Camunda licenses this file to you under the Apache License,
+ * Version 2.0; 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.camunda.connector.generator;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import io.camunda.connector.generator.core.OutboundElementTemplateGenerator;
+import io.camunda.connector.generator.dsl.OutboundElementTemplate;
+import java.io.File;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.ArrayList;
+import java.util.List;
+import org.apache.maven.artifact.Artifact;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.LifecyclePhase;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.plugins.annotations.ResolutionScope;
+import org.apache.maven.project.MavenProject;
+
+@Mojo(
+    name = "generate-templates",
+    defaultPhase = LifecyclePhase.PROCESS_CLASSES,
+    requiresDependencyResolution = ResolutionScope.COMPILE_PLUS_RUNTIME)
+public class ElementTemplateGeneratorMojo extends AbstractMojo {
+
+  @Parameter(defaultValue = "${project}", readonly = true, required = true)
+  private MavenProject project;
+
+  @Parameter(property = "connectorClasses", required = true)
+  private String[] connectorClasses;
+
+  @Parameter(property = "includeDependencies")
+  private String[] includeDependencies;
+
+  @Parameter(property = "outputDirectory", defaultValue = "${project.basedir}/element-templates")
+  private String outputDirectory;
+
+  private static final ObjectMapper mapper = new ObjectMapper();
+  private final OutboundElementTemplateGenerator generator = new OutboundElementTemplateGenerator();
+
+  private static final String COMPILED_CLASSES_DIR = "target" + File.separator + "classes";
+
+  @Override
+  public void execute() throws MojoFailureException {
+    if (connectorClasses.length == 0) {
+      getLog().warn("No connector classes specified. Skipping generation of element templates.");
+      return;
+    }
+
+    List<URL> classpathUrls = new ArrayList<>();
+
+    try {
+      String compiledClassesPath =
+          project.getFile().getParent() + File.separator + COMPILED_CLASSES_DIR;
+      classpathUrls.add(new File(compiledClassesPath).toURI().toURL());
+
+      for (String dependency : includeDependencies) {
+        Artifact dependencyArtifact = (Artifact) project.getArtifactMap().get(dependency);
+        if (dependencyArtifact == null) {
+          throw new IllegalArgumentException(
+              "Failed to find dependency " + dependency + " in project " + project.getName());
+        }
+        classpathUrls.add(dependencyArtifact.getFile().toURI().toURL());
+      }
+    } catch (Exception e) {
+      throw new MojoFailureException("Failed to load classpath: " + e.getMessage(), e);
+    }
+
+    try (URLClassLoader classLoader =
+        new URLClassLoader(
+            classpathUrls.toArray(new URL[0]), Thread.currentThread().getContextClassLoader())) {
+
+      for (String className : connectorClasses) {
+        getLog().info("Generating element template for " + className);
+        Class<?> clazz = classLoader.loadClass(className);
+        OutboundElementTemplate template = generateElementTemplate(clazz);
+        writeElementTemplate(template);
+      }
+
+    } catch (ClassNotFoundException e) {
+      throw new MojoFailureException("Failed to find connector class: " + e.getMessage(), e);
+    } catch (TypeNotPresentException e) {
+      throw new MojoFailureException(
+          e.getMessage()
+              + "\nIf your connector references other packages, include them using the 'includeDependencies' parameter",
+          e);
+    } catch (Exception e) {
+      throw new MojoFailureException("Failed to generate element templates: " + e.getMessage(), e);
+    }
+  }
+
+  private OutboundElementTemplate generateElementTemplate(Class<?> clazz) {
+    return generator.generate(clazz);
+  }
+
+  private void writeElementTemplate(OutboundElementTemplate template) {
+    try {
+      String fileName = transformConnectorNameToTemplateFileName(template.name());
+      File file = new File(outputDirectory, fileName);
+      file.getParentFile().mkdirs();
+      mapper.writerWithDefaultPrettyPrinter().writeValue(file, template);
+    } catch (Exception e) {
+      throw new RuntimeException("Failed to write element template", e);
+    }
+  }
+
+  private String transformConnectorNameToTemplateFileName(String connectorName) {
+    // convert human-oriented name to kebab-case
+    connectorName = connectorName.replaceAll(" ", "-");
+    connectorName = connectorName.replaceAll("([a-z])([A-Z]+)", "$1-$2");
+    connectorName = connectorName.toLowerCase();
+    return connectorName + ".json";
+  }
+}

connectors/pom.xml

@@ -112,6 +112,19 @@ except in compliance with the proprietary license.</license.inlineheader>
   <build>
     <pluginManagement>
       <plugins>
+        <plugin>
+          <groupId>io.camunda.connector</groupId>
+          <artifactId>element-template-generator-maven-plugin</artifactId>
+          <version>${project.version}</version>
+          <executions>
+            <execution>
+              <goals>
+                <goal>generate-templates</goal>
+              </goals>
+            </execution>
+          </executions>
+        </plugin>
+
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-shade-plugin</artifactId>

pom.xml

@@ -24,6 +24,7 @@
     <module>connector-sdk/test</module>
     <module>connector-sdk/jackson-datatype-feel</module>
     <module>connector-sdk/element-template-generator</module>
+    <module>connector-sdk/element-template-generator-maven-plugin</module>
     <module>secret-providers/gcp-secret-provider</module>
     <module>connector-runtime/connector-runtime-core</module>
     <module>connector-runtime/connector-runtime-spring</module>