Add Netflix DGS Codegen plugin support

This commit adds a new dependency to start.spring.io, the "Netflix Data
Graph Service Codegen". This will not add a dependency to generated
project, but rather configure a Maven or a Gradle plugin in the build.

This Codegen plugin parses GraphQL schema files describing remote
GraphQL APIs and generates Java classes to easily create queries and
deserialize GraphQL responses.

start-site/src/main/java/io/spring/start/site/extension/dependency/dgs/DgsCodegenBuildCustomizer.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.spring.start.site.extension.dependency.dgs;
+
+import io.spring.initializr.generator.buildsystem.Build;
+import io.spring.initializr.generator.spring.build.BuildCustomizer;
+
+import org.springframework.core.Ordered;
+
+/**
+ * {@link BuildCustomizer} that removes the "dgs-codegen" dependency as this is a build
+ * plugin only dependency.
+ *
+ * @author Brian Clozel
+ */
+class DgsCodegenBuildCustomizer implements BuildCustomizer<Build> {
+
+	@Override
+	public void customize(Build build) {
+		build.dependencies().remove("dgs-codegen");
+	}
+
+	@Override
+	public int getOrder() {
+		return Ordered.LOWEST_PRECEDENCE - 10;
+	}
+
+}

start-site/src/main/java/io/spring/start/site/extension/dependency/dgs/DgsCodegenGroovyDslGradleBuildCustomizer.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.spring.start.site.extension.dependency.dgs;
+
+import io.spring.initializr.generator.buildsystem.gradle.GradleBuild;
+import io.spring.initializr.generator.spring.build.BuildCustomizer;
+
+/**
+ * {@link BuildCustomizer} for Gradle Groovy DSL projects using DGS Codegen.
+ *
+ * @author Brian Clozel
+ */
+class DgsCodegenGroovyDslGradleBuildCustomizer implements BuildCustomizer<GradleBuild> {
+
+	private final String pluginVersion;
+
+	private final String packageName;
+
+	DgsCodegenGroovyDslGradleBuildCustomizer(String pluginVersion, String packageName) {
+		this.pluginVersion = pluginVersion;
+		this.packageName = packageName;
+	}
+
+	@Override
+	public void customize(GradleBuild build) {
+		build.plugins().add("com.netflix.dgs.codegen", (plugin) -> plugin.setVersion(this.pluginVersion));
+		build.snippets().add((writer) -> {
+			writer.println("generateJava {");
+			writer.indented(() -> {
+				writer.println("schemaPaths = [\"${projectDir}/src/main/resources/graphql-client\"]");
+				writer.println("packageName = '" + this.packageName + ".codegen'");
+				writer.println("generateClient = true");
+			});
+			writer.println("}");
+		});
+	}
+
+}

start-site/src/main/java/io/spring/start/site/extension/dependency/dgs/DgsCodegenHelpDocumentCustomizer.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.spring.start.site.extension.dependency.dgs;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import io.spring.initializr.generator.buildsystem.BuildSystem;
+import io.spring.initializr.generator.buildsystem.gradle.GradleBuildSystem;
+import io.spring.initializr.generator.buildsystem.maven.MavenBuildSystem;
+import io.spring.initializr.generator.project.ProjectDescription;
+import io.spring.initializr.generator.spring.documentation.HelpDocument;
+import io.spring.initializr.generator.spring.documentation.HelpDocumentCustomizer;
+
+/**
+ * Provide additional information when DGS Codegen Support is selected.
+ *
+ * @author Brian Clozel
+ */
+class DgsCodegenHelpDocumentCustomizer implements HelpDocumentCustomizer {
+
+	private final BuildSystem buildSystem;
+
+	DgsCodegenHelpDocumentCustomizer(ProjectDescription description) {
+		this.buildSystem = description.getBuildSystem();
+	}
+
+	@Override
+	public void customize(HelpDocument document) {
+		Map<String, Object> model = new HashMap<>();
+
+		if (MavenBuildSystem.ID.equals(this.buildSystem.id())) {
+			model.put("dsgCodegenOptionsLink", "https://github.com/deweyjose/graphqlcodegen");
+		}
+		else if (GradleBuildSystem.ID.equals(this.buildSystem.id())) {
+			model.put("dsgCodegenOptionsLink",
+					"https://netflix.github.io/dgs/generating-code-from-schema/#configuring-code-generation");
+		}
+		document.addSection("dgscodegen", model);
+	}
+
+}

start-site/src/main/java/io/spring/start/site/extension/dependency/dgs/DgsCodegenKotlinDslGradleBuildCustomizer.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.spring.start.site.extension.dependency.dgs;
+
+import io.spring.initializr.generator.buildsystem.gradle.GradleBuild;
+import io.spring.initializr.generator.spring.build.BuildCustomizer;
+
+/**
+ * {@link BuildCustomizer} for Gradle Kotlin DSL projects using DGS Codegen.
+ *
+ * @author Brian Clozel
+ */
+class DgsCodegenKotlinDslGradleBuildCustomizer implements BuildCustomizer<GradleBuild> {
+
+	private final String pluginVersion;
+
+	private final String packageName;
+
+	DgsCodegenKotlinDslGradleBuildCustomizer(String pluginVersion, String packageName) {
+		this.pluginVersion = pluginVersion;
+		this.packageName = packageName;
+	}
+
+	@Override
+	public void customize(GradleBuild build) {
+		build.plugins().add("com.netflix.dgs.codegen", (plugin) -> plugin.setVersion(this.pluginVersion));
+		build.snippets().add((writer) -> {
+			writer.println("tasks.generateJava {");
+			writer.indented(() -> {
+				writer.println("schemaPaths.add(\"${projectDir}/src/main/resources/graphql-client\")");
+				writer.println("packageName = \"" + this.packageName + ".codegen\"");
+				writer.println("generateClient = true");
+			});
+			writer.println("}");
+		});
+	}
+
+}

start-site/src/main/java/io/spring/start/site/extension/dependency/dgs/DgsCodegenMavenBuildCustomizer.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.spring.start.site.extension.dependency.dgs;
+
+import io.spring.initializr.generator.buildsystem.maven.MavenBuild;
+import io.spring.initializr.generator.spring.build.BuildCustomizer;
+
+/**
+ * {@link BuildCustomizer} for Maven projects using DGS Codegen (community maintained).
+ *
+ * @author Brian Clozel
+ * @see <a href="https://github.com/deweyjose/graphqlcodegen">Maven GraphQL Codegen
+ * plugin</a>
+ */
+public class DgsCodegenMavenBuildCustomizer implements BuildCustomizer<MavenBuild> {
+
+	private final String pluginVersion;
+
+	private final String packageName;
+
+	public DgsCodegenMavenBuildCustomizer(String pluginVersion, String packageName) {
+		this.pluginVersion = pluginVersion;
+		this.packageName = packageName;
+	}
+
+	@Override
+	public void customize(MavenBuild build) {
+		build.plugins()
+			.add("io.github.deweyjose", "graphqlcodegen-maven-plugin",
+					(plugin) -> plugin.version(this.pluginVersion)
+						.execution("dgs-codegen",
+								(execution) -> execution.goal("generate")
+									.configuration((configuration) -> configuration
+										.add("schemaPaths",
+												(schemaPaths) -> schemaPaths.add("param",
+														"src/main/resources/graphql-client"))
+										.add("packageName", this.packageName + ".codegen")
+										.add("addGeneratedAnnotation", "true"))));
+		build.plugins()
+			.add("org.codehaus.mojo", "build-helper-maven-plugin",
+					(plugin) -> plugin.execution("add-dgs-source", (execution) -> execution.goal("add-source")
+						.phase("generate-sources")
+						.configuration((configuration) -> configuration.add("sources",
+								(sources) -> sources.add("source", "${project.build.directory}/generated-sources")))));
+	}
+
+}

start-site/src/main/java/io/spring/start/site/extension/dependency/dgs/DgsCodegenProjectContributor.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.spring.start.site.extension.dependency.dgs;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import io.spring.initializr.generator.project.contributor.ProjectContributor;
+
+/**
+ * A {@link ProjectContributor} that creates the "graphql-client" resources directory when
+ * the DGS Codegen build plugin is requested.
+ *
+ * @author Brian Clozel
+ */
+class DgsCodegenProjectContributor implements ProjectContributor {
+
+	@Override
+	public void contribute(Path projectRoot) throws IOException {
+		Path graphQlDirectory = projectRoot.resolve("src/main/resources/graphql-client");
+		Files.createDirectories(graphQlDirectory);
+	}
+
+}

start-site/src/main/java/io/spring/start/site/extension/dependency/dgs/DgsCodegenProjectGenerationConfiguration.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.spring.start.site.extension.dependency.dgs;
+
+import io.spring.initializr.generator.buildsystem.gradle.GradleBuildSystem;
+import io.spring.initializr.generator.buildsystem.maven.MavenBuildSystem;
+import io.spring.initializr.generator.condition.ConditionalOnBuildSystem;
+import io.spring.initializr.generator.condition.ConditionalOnPlatformVersion;
+import io.spring.initializr.generator.condition.ConditionalOnRequestedDependency;
+import io.spring.initializr.generator.project.ProjectDescription;
+import io.spring.initializr.generator.project.ProjectGenerationConfiguration;
+import io.spring.initializr.metadata.InitializrMetadata;
+
+import org.springframework.context.annotation.Bean;
+
+/**
+ * {@link ProjectGenerationConfiguration} for generation of projects that use the Netflix
+ * DGS codegen.
+ *
+ * @author Brian Clozel
+ * @see <a href="https://netflix.github.io/dgs/generating-code-from-schema/">Netflix DGS
+ * codegen</a>
+ */
+@ProjectGenerationConfiguration
+@ConditionalOnRequestedDependency("dgs-codegen")
+@ConditionalOnPlatformVersion("3.0.0-M1")
+class DgsCodegenProjectGenerationConfiguration {
+
+	private final String dgsCodegenPluginVersion;
+
+	DgsCodegenProjectGenerationConfiguration(InitializrMetadata metadata, ProjectDescription description) {
+		this.dgsCodegenPluginVersion = DgsCodegenVersionResolver.resolve(metadata, description.getPlatformVersion(),
+				description.getBuildSystem());
+	}
+
+	@Bean
+	DgsCodegenBuildCustomizer dgsCodegenBuildCustomizer() {
+		return new DgsCodegenBuildCustomizer();
+	}
+
+	@Bean
+	DgsCodegenProjectContributor dgsCodegenProjectContributor() {
+		return new DgsCodegenProjectContributor();
+	}
+
+	@Bean
+	DgsCodegenHelpDocumentCustomizer dgsCodegenHelpDocumentCustomizer(ProjectDescription description) {
+		return new DgsCodegenHelpDocumentCustomizer(description);
+	}
+
+	@Bean
+	@ConditionalOnBuildSystem(id = GradleBuildSystem.ID, dialect = GradleBuildSystem.DIALECT_GROOVY)
+	DgsCodegenGroovyDslGradleBuildCustomizer dgsCodegenGroovyDslGradleBuildCustomizer(ProjectDescription description) {
+		return new DgsCodegenGroovyDslGradleBuildCustomizer(this.dgsCodegenPluginVersion, description.getPackageName());
+	}
+
+	@Bean
+	@ConditionalOnBuildSystem(id = GradleBuildSystem.ID, dialect = GradleBuildSystem.DIALECT_KOTLIN)
+	DgsCodegenKotlinDslGradleBuildCustomizer dgsCodegenKotlinDslGradleBuildCustomizer(ProjectDescription description) {
+		return new DgsCodegenKotlinDslGradleBuildCustomizer(this.dgsCodegenPluginVersion, description.getPackageName());
+	}
+
+	@Bean
+	@ConditionalOnBuildSystem(MavenBuildSystem.ID)
+	DgsCodegenMavenBuildCustomizer dgsCodegenMavenBuildCustomizer(ProjectDescription description) {
+		return new DgsCodegenMavenBuildCustomizer(this.dgsCodegenPluginVersion, description.getPackageName());
+	}
+
+}