Polish "Add support for Docker Compose"

See gh-1417

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/container/docker/compose/ComposeProjectContributor.java

@@ -0,0 +1,63 @@
+/*
+ * 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.initializr.generator.spring.container.docker.compose;
+
+import java.io.IOException;
+import java.io.Writer;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import io.spring.initializr.generator.container.docker.compose.ComposeFile;
+import io.spring.initializr.generator.container.docker.compose.ComposeFileWriter;
+import io.spring.initializr.generator.io.IndentingWriter;
+import io.spring.initializr.generator.io.IndentingWriterFactory;
+import io.spring.initializr.generator.project.contributor.ProjectContributor;
+
+/**
+ * A {@link ProjectContributor} that creates a 'compose.yaml' file through a
+ * {@link ComposeFile}.
+ *
+ * @author Moritz Halbritter
+ * @author Stephane Nicoll
+ */
+public class ComposeProjectContributor implements ProjectContributor {
+
+	private final ComposeFile composeFile;
+
+	private final IndentingWriterFactory indentingWriterFactory;
+
+	private final ComposeFileWriter composeFileWriter;
+
+	public ComposeProjectContributor(ComposeFile composeFile, IndentingWriterFactory indentingWriterFactory) {
+		this.composeFile = composeFile;
+		this.indentingWriterFactory = indentingWriterFactory;
+		this.composeFileWriter = new ComposeFileWriter();
+	}
+
+	@Override
+	public void contribute(Path projectRoot) throws IOException {
+		Path file = Files.createFile(projectRoot.resolve("compose.yaml"));
+		writeComposeFile(Files.newBufferedWriter(file));
+	}
+
+	void writeComposeFile(Writer out) throws IOException {
+		try (IndentingWriter writer = this.indentingWriterFactory.createIndentingWriter("yaml", out)) {
+			this.composeFileWriter.writeTo(writer, this.composeFile);
+		}
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/container/docker/compose/DockerComposeHelpDocumentCustomizer.java

@@ -14,35 +14,35 @@
  * limitations under the License.
  */
 
-package io.spring.initializr.generator.spring.container.dockercompose;
+package io.spring.initializr.generator.spring.container.docker.compose;
 
-import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 
-import io.spring.initializr.generator.spring.container.dockercompose.Markdown.MarkdownTable;
+import io.spring.initializr.generator.container.docker.compose.ComposeFile;
+import io.spring.initializr.generator.container.docker.compose.ComposeService;
+import io.spring.initializr.generator.spring.container.docker.compose.Markdown.MarkdownTable;
 import io.spring.initializr.generator.spring.documentation.HelpDocument;
 import io.spring.initializr.generator.spring.documentation.HelpDocumentCustomizer;
 
 /**
- * Provide additional information in the {@link HelpDocument} if the
+ * A {@link HelpDocumentCustomizer} that provide additional information about the
- * {@link DockerComposeFile} isn't empty.
+ * {@link ComposeService compose services} that are defined for the project.
  *
  * @author Moritz Halbritter
  */
-class DockerComposeHelpDocumentCustomizer implements HelpDocumentCustomizer {
+public class DockerComposeHelpDocumentCustomizer implements HelpDocumentCustomizer {
 
-	private final DockerComposeFile composeFile;
+	private final ComposeFile composeFile;
 
-	DockerComposeHelpDocumentCustomizer(DockerComposeFile composeFile) {
+	public DockerComposeHelpDocumentCustomizer(ComposeFile composeFile) {
 		this.composeFile = composeFile;
 	}
 
 	@Override
 	public void customize(HelpDocument document) {
-		Collection<DockerComposeService> services = this.composeFile.getServices();
 		Map<String, Object> model = new HashMap<>();
-		if (services.isEmpty()) {
+		if (this.composeFile.services().isEmpty()) {
 			model.put("serviceTable", null);
 			document.getWarnings()
 				.addItem(
@@ -50,10 +50,10 @@ class DockerComposeHelpDocumentCustomizer implements HelpDocumentCustomizer {
 		}
 		else {
 			MarkdownTable serviceTable = Markdown.table("Service name", "Image", "Tag", "Website");
-			for (DockerComposeService service : services) {
+			this.composeFile.services()
-				serviceTable.addRow(service.getName(), Markdown.code(service.getImage()),
+				.values()
-						Markdown.code(service.getImageTag()), Markdown.link("Website", service.getImageWebsite()));
+				.forEach((service) -> serviceTable.addRow(service.getName(), Markdown.code(service.getImage()),
-			}
+						Markdown.code(service.getImageTag()), Markdown.link("Website", service.getImageWebsite())));
 			model.put("serviceTable", serviceTable.toMarkdown());
 		}
 		document.addSection("documentation/docker-compose", model);

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/container/docker/compose/Markdown.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package io.spring.initializr.generator.spring.container.dockercompose;
+package io.spring.initializr.generator.spring.container.docker.compose;
 
 import java.util.ArrayList;
 import java.util.List;

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/container/docker/compose/package-info.java

@@ -17,4 +17,4 @@
 /**
  * Support for Docker Compose.
  */
-package io.spring.initializr.generator.spring.container.dockercompose;
+package io.spring.initializr.generator.spring.container.docker.compose;

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeFile.java

@@ -1,70 +0,0 @@
-/*
- * 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.initializr.generator.spring.container.dockercompose;
-
-import java.io.PrintWriter;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Map;
-import java.util.TreeMap;
-
-/**
- * A Docker Compose file.
- *
- * @author Moritz Halbritter
- */
-public class DockerComposeFile {
-
-	// TreeMap to sort services by name
-	private final Map<String, DockerComposeService> services = new TreeMap<>();
-
-	/**
-	 * Adds a {@link DockerComposeService service} to the file. If a service with the same
-	 * {@link DockerComposeService#getName() name} already exists, it is replaced.
-	 * @param service the service to add
-	 * @return {@code this}
-	 */
-	public DockerComposeFile addService(DockerComposeService service) {
-		this.services.put(service.getName(), service);
-		return this;
-	}
-
-	/**
-	 * Returns the service with the given name.
-	 * @param name the name
-	 * @return the service or {@code null} if no service with the given name exists
-	 */
-	public DockerComposeService getService(String name) {
-		return this.services.get(name);
-	}
-
-	/**
-	 * Returns all services.
-	 * @return all services
-	 */
-	public Collection<DockerComposeService> getServices() {
-		return Collections.unmodifiableCollection(this.services.values());
-	}
-
-	void write(PrintWriter writer) {
-		writer.println("services:");
-		for (DockerComposeService service : this.services.values()) {
-			service.write(writer, 1);
-		}
-	}
-
-}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeFileCustomizer.java

@@ -1,42 +0,0 @@
-/*
- * 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.initializr.generator.spring.container.dockercompose;
-
-import org.springframework.core.Ordered;
-
-/**
- * Callback for customizing a project's {@link DockerComposeFile}. Invoked with an
- * {@link Ordered order} of {@code 0} by default, considering overriding
- * {@link #getOrder()} to customize this behaviour.
- *
- * @author Moritz Halbritter
- */
-@FunctionalInterface
-public interface DockerComposeFileCustomizer extends Ordered {
-
-	/**
-	 * Customizes the given {@link DockerComposeFile}.
-	 * @param composeFile the compose file to customize
-	 */
-	void customize(DockerComposeFile composeFile);
-
-	@Override
-	default int getOrder() {
-		return 0;
-	}
-
-}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeProjectContributor.java

@@ -1,48 +0,0 @@
-/*
- * 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.initializr.generator.spring.container.dockercompose;
-
-import java.io.IOException;
-import java.io.PrintWriter;
-import java.nio.file.Files;
-import java.nio.file.Path;
-
-import io.spring.initializr.generator.project.contributor.ProjectContributor;
-
-/**
- * A {@link ProjectContributor} which contributes a 'compose.yaml' file through a
- * {@link DockerComposeFile}.
- *
- * @author Moritz Halbritter
- */
-class DockerComposeProjectContributor implements ProjectContributor {
-
-	private final DockerComposeFile composeFile;
-
-	DockerComposeProjectContributor(DockerComposeFile composeFile) {
-		this.composeFile = composeFile;
-	}
-
-	@Override
-	public void contribute(Path projectRoot) throws IOException {
-		Path file = Files.createFile(projectRoot.resolve("compose.yaml"));
-		try (PrintWriter writer = new PrintWriter(Files.newBufferedWriter(file))) {
-			this.composeFile.write(writer);
-		}
-	}
-
-}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeProjectGenerationConfiguration.java

@@ -1,49 +0,0 @@
-/*
- * 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.initializr.generator.spring.container.dockercompose;
-
-import io.spring.initializr.generator.project.ProjectGenerationConfiguration;
-
-import org.springframework.beans.factory.ObjectProvider;
-import org.springframework.context.annotation.Bean;
-
-/**
- * Configuration for contributions specific to the Docker Compose parts of a project.
- *
- * @author Moritz Halbritter
- */
-@ProjectGenerationConfiguration
-public class DockerComposeProjectGenerationConfiguration {
-
-	@Bean
-	DockerComposeFile composeFile(ObjectProvider<DockerComposeFileCustomizer> composeFileCustomizers) {
-		DockerComposeFile composeFile = new DockerComposeFile();
-		composeFileCustomizers.orderedStream().forEach((customizer) -> customizer.customize(composeFile));
-		return composeFile;
-	}
-
-	@Bean
-	DockerComposeProjectContributor dockerComposeProjectContributor(DockerComposeFile composeFile) {
-		return new DockerComposeProjectContributor(composeFile);
-	}
-
-	@Bean
-	DockerComposeHelpDocumentCustomizer dockerComposeHelpDocumentCustomizer(DockerComposeFile composeFile) {
-		return new DockerComposeHelpDocumentCustomizer(composeFile);
-	}
-
-}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeService.java

@@ -1,254 +0,0 @@
-/*
- * 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.initializr.generator.spring.container.dockercompose;
-
-import java.io.PrintWriter;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Set;
-import java.util.TreeMap;
-import java.util.TreeSet;
-
-/**
- * A Docker Compose service.
- *
- * @author Moritz Halbritter
- */
-public final class DockerComposeService {
-
-	private static final String INDENT = "  ";
-
-	private final String name;
-
-	private final String image;
-
-	private final String imageTag;
-
-	private final String imageWebsite;
-
-	private final Map<String, String> environment;
-
-	private final Set<Integer> ports;
-
-	private DockerComposeService(Builder builder) {
-		this.name = builder.name;
-		this.image = builder.image;
-		this.imageTag = builder.imageTag;
-		this.imageWebsite = builder.imageWebsite;
-		this.environment = builder.environment;
-		this.ports = builder.ports;
-	}
-
-	public String getName() {
-		return this.name;
-	}
-
-	public String getImage() {
-		return this.image;
-	}
-
-	public String getImageTag() {
-		return this.imageTag;
-	}
-
-	public String getImageWebsite() {
-		return this.imageWebsite;
-	}
-
-	public Map<String, String> getEnvironment() {
-		return Collections.unmodifiableMap(this.environment);
-	}
-
-	public Set<Integer> getPorts() {
-		return Collections.unmodifiableSet(this.ports);
-	}
-
-	@Override
-	public boolean equals(Object o) {
-		if (this == o) {
-			return true;
-		}
-		if (o == null || getClass() != o.getClass()) {
-			return false;
-		}
-		DockerComposeService service = (DockerComposeService) o;
-		return Objects.equals(this.name, service.name) && Objects.equals(this.image, service.image)
-				&& Objects.equals(this.imageTag, service.imageTag)
-				&& Objects.equals(this.imageWebsite, service.imageWebsite)
-				&& Objects.equals(this.environment, service.environment) && Objects.equals(this.ports, service.ports);
-	}
-
-	@Override
-	public int hashCode() {
-		return Objects.hash(this.name, this.image, this.imageTag, this.imageWebsite, this.environment, this.ports);
-	}
-
-	@Override
-	public String toString() {
-		return "DockerComposeService{" + "name='" + this.name + '\'' + ", image='" + this.image + '\'' + ", imageTag='"
-				+ this.imageTag + '\'' + ", imageWebsite='" + this.imageWebsite + '\'' + ", environment="
-				+ this.environment + ", ports=" + this.ports + '}';
-	}
-
-	void write(PrintWriter writer, int indentation) {
-		int currentIndent = indentation;
-		println(writer, this.name + ":", currentIndent);
-		currentIndent++;
-		println(writer, "image: '%s:%s'".formatted(this.image, this.imageTag), currentIndent);
-		if (!this.environment.isEmpty()) {
-			writeEnvironment(writer, currentIndent);
-		}
-		if (!this.ports.isEmpty()) {
-			writePorts(writer, currentIndent);
-		}
-	}
-
-	private void writePorts(PrintWriter writer, int currentIndent) {
-		println(writer, "ports:", currentIndent);
-		for (Integer port : this.ports) {
-			println(writer, "- '%d'".formatted(port), currentIndent + 1);
-		}
-	}
-
-	private void writeEnvironment(PrintWriter writer, int currentIndent) {
-		println(writer, "environment:", currentIndent);
-		for (Map.Entry<String, String> env : this.environment.entrySet()) {
-			println(writer, "- '%s=%s'".formatted(env.getKey(), env.getValue()), currentIndent + 1);
-		}
-	}
-
-	private void println(PrintWriter writer, String value, int indentation) {
-		writer.write(INDENT.repeat(indentation));
-		writer.println(value);
-	}
-
-	/**
-	 * Initialize a new {@link Builder} with the given image. The name is automatically
-	 * deduced.
-	 * @param image the image
-	 * @param tag the image tag
-	 * @return a new builder
-	 */
-	public static Builder withImage(String image, String tag) {
-		// See https://github.com/docker/compose/pull/1624
-		String name = image.replaceAll("[^a-zA-Z0-9._\\-]", "_");
-		return new Builder(name, image, tag);
-	}
-
-	/**
-	 * Initialize a new {@link Builder} with the given image. The name is automatically
-	 * deduced.
-	 * @param imageAndTag the image and tag in the format {@code image:tag}
-	 * @return a new builder
-	 */
-	public static Builder withImage(String imageAndTag) {
-		String[] split = imageAndTag.split(":", 2);
-		if (split.length == 1) {
-			return withImage(split[0], "latest");
-		}
-		else {
-			return withImage(split[0], split[1]);
-		}
-	}
-
-	/**
-	 * Initialize a {@link Builder} with the given service.
-	 * @param service the service to initialize from
-	 * @return a new builder
-	 */
-	public static Builder from(DockerComposeService service) {
-		return new Builder(service.name, service.image, service.imageTag).imageWebsite(service.imageWebsite)
-			.environment(service.environment)
-			.ports(service.ports);
-	}
-
-	/**
-	 * Builder for {@link DockerComposeService}.
-	 */
-	public static final class Builder {
-
-		private String name;
-
-		private String image;
-
-		private String imageTag;
-
-		private String imageWebsite;
-
-		private final Map<String, String> environment = new TreeMap<>();
-
-		private final Set<Integer> ports = new TreeSet<>();
-
-		private Builder(String name, String image, String imageTag) {
-			this.name = name;
-			this.image = image;
-			this.imageTag = imageTag;
-		}
-
-		public Builder name(String name) {
-			this.name = name;
-			return this;
-		}
-
-		public Builder image(String image) {
-			this.image = image;
-			return this;
-		}
-
-		public Builder imageTag(String imageTag) {
-			this.imageTag = imageTag;
-			return this;
-		}
-
-		public Builder imageWebsite(String imageWebsite) {
-			this.imageWebsite = imageWebsite;
-			return this;
-		}
-
-		public Builder environment(String key, String value) {
-			this.environment.put(key, value);
-			return this;
-		}
-
-		public Builder environment(Map<String, String> environment) {
-			this.environment.putAll(environment);
-			return this;
-		}
-
-		public Builder ports(Collection<Integer> ports) {
-			this.ports.addAll(ports);
-			return this;
-		}
-
-		public Builder ports(int... ports) {
-			return ports(Arrays.stream(ports).boxed().toList());
-		}
-
-		/**
-		 * Builds the {@link DockerComposeService} instance.
-		 * @return the built instance
-		 */
-		public DockerComposeService build() {
-			return new DockerComposeService(this);
-		}
-
-	}
-
-}

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/container/docker/compose/ComposeProjectContributorTests.java

@@ -0,0 +1,73 @@
+/*
+ * 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.initializr.generator.spring.container.docker.compose;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.nio.file.Path;
+
+import io.spring.initializr.generator.container.docker.compose.ComposeFile;
+import io.spring.initializr.generator.io.IndentingWriterFactory;
+import io.spring.initializr.generator.io.SimpleIndentStrategy;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link ComposeProjectContributor}.
+ *
+ * @author Moritz Halbritter
+ * @author Stephane Nicoll
+ */
+class ComposeProjectContributorTests {
+
+	@Test
+	void composeFileIsContributedInProjectStructure(@TempDir Path projectDir) throws IOException {
+		ComposeFile compose = new ComposeFile();
+		compose.services().add("test", (service) -> service.image("my-image:1.2.3"));
+		new ComposeProjectContributor(compose, IndentingWriterFactory.withDefaultSettings()).contribute(projectDir);
+		Path composeFile = projectDir.resolve("compose.yaml");
+		assertThat(composeFile).isRegularFile();
+	}
+
+	@Test
+	void composeFileIsContributedUsingYamlContentId() throws IOException {
+		IndentingWriterFactory indentingWriterFactory = IndentingWriterFactory.create(new SimpleIndentStrategy("    "),
+				(factory) -> factory.indentingStrategy("yaml", new SimpleIndentStrategy("\t")));
+		ComposeFile composeFile = new ComposeFile();
+		composeFile.services()
+			.add("test", (service) -> service.imageAndTag("image:1.3.3").environment("a", "aa").environment("b", "bb"));
+		assertThat(generateComposeFile(composeFile, indentingWriterFactory)).isEqualToIgnoringNewLines("""
+				services:
+					test:
+						image: 'image:1.3.3'
+						environment:
+							- 'a=aa'
+							- 'b=bb'
+				""");
+
+	}
+
+	private String generateComposeFile(ComposeFile composeFile, IndentingWriterFactory indentingWriterFactory)
+			throws IOException {
+		StringWriter writer = new StringWriter();
+		new ComposeProjectContributor(composeFile, indentingWriterFactory).writeComposeFile(writer);
+		return writer.toString();
+	}
+
+}

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/container/docker/compose/DockerComposeHelpDocumentCustomizerTests.java

@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-package io.spring.initializr.generator.spring.container.dockercompose;
+package io.spring.initializr.generator.spring.container.docker.compose;
 
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.io.StringWriter;
 
+import io.spring.initializr.generator.container.docker.compose.ComposeFile;
 import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
 import io.spring.initializr.generator.io.text.MustacheSection;
 import io.spring.initializr.generator.io.text.Section;
@@ -38,17 +39,18 @@ class DockerComposeHelpDocumentCustomizerTests {
 
 	private DockerComposeHelpDocumentCustomizer customizer;
 
-	private DockerComposeFile dockerComposeFile;
+	private ComposeFile dockerComposeFile;
 
 	@BeforeEach
 	void setUp() {
-		this.dockerComposeFile = new DockerComposeFile();
+		this.dockerComposeFile = new ComposeFile();
 		this.customizer = new DockerComposeHelpDocumentCustomizer(this.dockerComposeFile);
 	}
 
 	@Test
 	void addsDockerComposeSection() throws IOException {
-		this.dockerComposeFile.addService(DockerComposeServiceHelper.service());
+		this.dockerComposeFile.services()
+			.add("test", (service) -> service.imageAndTag("image-1:1.2.3").imageWebsite("https:/example.com/image-1"));
 		HelpDocument helpDocument = helpDocument();
 		this.customizer.customize(helpDocument);
 		assertThat(helpDocument.getSections()).hasSize(1);
@@ -63,9 +65,9 @@ class DockerComposeHelpDocumentCustomizerTests {
 
 				In this file, the following services have been defined:
 
-				| Service name | Image     | Tag           | Website                           |
+				| Service name | Image     | Tag     | Website                               |
-				| ------------ | --------- | ------------- | --------------------------------- |
+				| ------------ | --------- | ------- | ------------------------------------- |
-				| service-1    | `image-1` | `image-tag-1` | [Website](https://service-1.org/) |
+				| test         | `image-1` | `1.2.3` | [Website](https:/example.com/image-1) |
 
 
 				Please review the tags of the used images and set them to the same as you're running in production.""");

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/container/docker/compose/MarkdownTests.java

@@ -14,20 +14,32 @@
  * limitations under the License.
  */
 
-package io.spring.initializr.generator.spring.container.dockercompose;
+package io.spring.initializr.generator.spring.container.docker.compose;
 
-import io.spring.initializr.generator.spring.container.dockercompose.Markdown.MarkdownTable;
+import io.spring.initializr.generator.spring.container.docker.compose.Markdown.MarkdownTable;
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 /**
- * Tests for {@link MarkdownTable}.
+ * Tests for {@link Markdown}.
  *
  * @author Moritz Halbritter
  */
-class MarkdownTableTests {
+class MarkdownTests {
+
+	@Test
+	void shouldFormatCode() {
+		String code = Markdown.code("c = a + b");
+		assertThat(code).isEqualTo("`c = a + b`");
+	}
+
+	@Test
+	void shouldFormatLink() {
+		String link = Markdown.link("Spring Website", "https://spring.io/");
+		assertThat(link).isEqualTo("[Spring Website](https://spring.io/)");
+	}
 
 	@Test
 	void shouldFormatCorrectly() {

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeFileTests.java

@@ -1,58 +0,0 @@
-/*
- * 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.initializr.generator.spring.container.dockercompose;
-
-import java.io.PrintWriter;
-import java.io.StringWriter;
-
-import org.junit.jupiter.api.Test;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-/**
- * Tests for {@link DockerComposeFile}.
- *
- * @author Moritz Halbritter
- */
-class DockerComposeFileTests {
-
-	@Test
-	void write() {
-		DockerComposeFile file = new DockerComposeFile();
-		file.addService(DockerComposeServiceHelper.service(1));
-		file.addService(DockerComposeServiceHelper.service(2));
-		StringWriter writer = new StringWriter();
-		file.write(new PrintWriter(writer));
-		assertThat(writer.toString()).isEqualToIgnoringNewLines("""
-				services:
-				  service-1:
-				    image: 'image-1:image-tag-1'
-				  service-2:
-				    image: 'image-2:image-tag-2'
-				""");
-	}
-
-	@Test
-	void servicesAreOrderedByName() {
-		DockerComposeFile file = new DockerComposeFile();
-		file.addService(DockerComposeServiceHelper.service(2));
-		file.addService(DockerComposeServiceHelper.service(1));
-		assertThat(file.getServices()).containsExactly(DockerComposeServiceHelper.service(1),
-				DockerComposeServiceHelper.service(2));
-	}
-
-}

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeProjectContributorTests.java

@@ -1,53 +0,0 @@
-/*
- * 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.initializr.generator.spring.container.dockercompose;
-
-import java.io.IOException;
-import java.nio.charset.StandardCharsets;
-import java.nio.file.Path;
-
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.io.TempDir;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-/**
- * Tests for {@link DockerComposeProjectContributor}.
- *
- * @author Moritz Halbritter
- */
-class DockerComposeProjectContributorTests {
-
-	private DockerComposeProjectContributor contributor;
-
-	private DockerComposeFile dockerComposeFile;
-
-	@BeforeEach
-	void setUp() {
-		this.dockerComposeFile = new DockerComposeFile();
-		this.contributor = new DockerComposeProjectContributor(this.dockerComposeFile);
-	}
-
-	@Test
-	void writesComposeYamlFile(@TempDir Path tempDir) throws IOException {
-		this.dockerComposeFile.addService(DockerComposeServiceHelper.service());
-		this.contributor.contribute(tempDir);
-		assertThat(tempDir.resolve("compose.yaml")).content(StandardCharsets.UTF_8).startsWith("services:");
-	}
-
-}

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeProjectGenerationConfigurationTests.java

@@ -1,71 +0,0 @@
-/*
- * 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.initializr.generator.spring.container.dockercompose;
-
-import org.junit.jupiter.api.Test;
-
-import org.springframework.boot.test.context.runner.ApplicationContextRunner;
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-/**
- * Tests for {@link DockerComposeProjectGenerationConfiguration}.
- *
- * @author Moritz Halbritter
- */
-class DockerComposeProjectGenerationConfigurationTests {
-
-	private final ApplicationContextRunner runner = new ApplicationContextRunner()
-		.withUserConfiguration(DockerComposeProjectGenerationConfiguration.class);
-
-	@Test
-	void providesBeans() {
-		this.runner.run((context) -> {
-			assertThat(context).hasSingleBean(DockerComposeFile.class);
-			assertThat(context).hasSingleBean(DockerComposeProjectContributor.class);
-			assertThat(context).hasSingleBean(DockerComposeHelpDocumentCustomizer.class);
-		});
-	}
-
-	@Test
-	void callsCustomizers() {
-		DockerComposeService service = DockerComposeServiceHelper.service(3);
-		DockerComposeFileCustomizer customizer = (composeFile) -> composeFile.addService(service);
-		this.runner.withBean(DockerComposeFileCustomizer.class, () -> customizer).run((context) -> {
-			DockerComposeFile composeFile = context.getBean(DockerComposeFile.class);
-			assertThat(composeFile.getServices()).containsExactly(service);
-		});
-	}
-
-	@Configuration
-	static class Services {
-
-		@Bean
-		DockerComposeService service1() {
-			return DockerComposeServiceHelper.service(1);
-		}
-
-		@Bean
-		DockerComposeService service2() {
-			return DockerComposeServiceHelper.service(2);
-		}
-
-	}
-
-}

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeServiceHelper.java

@@ -1,49 +0,0 @@
-/*
- * 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.initializr.generator.spring.container.dockercompose;
-
-/**
- * Helper class for {@link DockerComposeService}.
- *
- * @author Moritz Halbritter
- */
-final class DockerComposeServiceHelper {
-
-	private DockerComposeServiceHelper() {
-	}
-
-	/**
-	 * Creates a new {@link DockerComposeService}.
-	 * @return a new {@link DockerComposeService}
-	 */
-	static DockerComposeService service() {
-		return service(1);
-	}
-
-	/**
-	 * Creates a new {@link DockerComposeService} with the given suffix.
-	 * @param suffix the suffix
-	 * @return a new {@link DockerComposeService}
-	 */
-	static DockerComposeService service(int suffix) {
-		return DockerComposeService.withImage("image-" + suffix, "image-tag-" + suffix)
-			.name("service-" + suffix)
-			.imageWebsite("https://service-" + suffix + ".org/")
-			.build();
-	}
-
-}

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeServiceTests.java

@@ -1,116 +0,0 @@
-/*
- * 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.initializr.generator.spring.container.dockercompose;
-
-import java.io.PrintWriter;
-import java.io.StringWriter;
-import java.util.Map;
-
-import org.junit.jupiter.api.Test;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.entry;
-
-/**
- * Tests for {@link DockerComposeService}.
- *
- * @author Moritz Halbritter
- */
-class DockerComposeServiceTests {
-
-	@Test
-	void shouldWriteToPrinter() {
-		StringWriter stringWriter = new StringWriter();
-		DockerComposeService service = DockerComposeService.withImage("elasticsearch:8.6.1")
-			.imageWebsite("https://www.docker.elastic.co/r/elasticsearch")
-			.environment("ELASTIC_PASSWORD", "secret")
-			.environment("discovery.type", "single-node")
-			.ports(9200, 9300)
-			.build();
-		service.write(new PrintWriter(stringWriter), 0);
-		String content = stringWriter.toString();
-		assertThat(content).isEqualToIgnoringNewLines("""
-				elasticsearch:
-				  image: 'elasticsearch:8.6.1'
-				  environment:
-				    - 'ELASTIC_PASSWORD=secret'
-				    - 'discovery.type=single-node'
-				  ports:
-				    - '9200'
-				    - '9300'
-				""");
-	}
-
-	@Test
-	void nameIsDeduced() {
-		DockerComposeService service = DockerComposeService.withImage("elasticsearch:8.6.1").build();
-		assertThat(service.getName()).isEqualTo("elasticsearch");
-	}
-
-	@Test
-	void tagIsSetToLatestIfNotGiven() {
-		DockerComposeService service = DockerComposeService.withImage("redis").build();
-		assertThat(service.getImage()).isEqualTo("redis");
-		assertThat(service.getImageTag()).isEqualTo("latest");
-	}
-
-	@Test
-	void removesIllegalCharsFromDecudedName() {
-		DockerComposeService service = DockerComposeService.withImage("SOME._-name<>;|\uD83C\uDF31").build();
-		assertThat(service.getName()).isEqualTo("SOME._-name_____");
-	}
-
-	@Test
-	void portsAreSorted() {
-		DockerComposeService service = DockerComposeService.withImage("redis").ports(5, 3, 4, 2, 1).build();
-		assertThat(service.getPorts()).containsExactly(1, 2, 3, 4, 5);
-	}
-
-	@Test
-	void environmentIsSorted() {
-		DockerComposeService service = DockerComposeService.withImage("redis")
-			.environment("z", "zz")
-			.environment("a", "aa")
-			.build();
-		assertThat(service.getEnvironment()).containsExactly(entry("a", "aa"), entry("z", "zz"));
-	}
-
-	@Test
-	void builderFrom() {
-		DockerComposeService service = DockerComposeService.withImage("elasticsearch", "8.6.1")
-			.imageWebsite("https://hub.docker.com/_/redis")
-			.environment(Map.of("some", "value"))
-			.ports(6379)
-			.build();
-		DockerComposeService service2 = DockerComposeService.from(service).build();
-		assertThat(service).isEqualTo(service2);
-	}
-
-	@Test
-	void equalsAndHashcode() {
-		DockerComposeService service1 = DockerComposeService.withImage("redis").build();
-		DockerComposeService service2 = DockerComposeService.withImage("elasticsearch:8.6.1").build();
-		DockerComposeService service3 = DockerComposeService.withImage("redis").build();
-		assertThat(service1).isEqualTo(service3);
-		assertThat(service1).hasSameHashCodeAs(service3);
-		assertThat(service3).isEqualTo(service1);
-		assertThat(service3).hasSameHashCodeAs(service1);
-		assertThat(service1).isNotEqualTo(service2);
-		assertThat(service2).isNotEqualTo(service1);
-	}
-
-}

initializr-generator/src/main/java/io/spring/initializr/generator/container/docker/compose/ComposeFile.java

@@ -14,29 +14,25 @@
  * limitations under the License.
  */
 
-package io.spring.initializr.generator.spring.container.dockercompose;
+package io.spring.initializr.generator.container.docker.compose;
-
-import org.junit.jupiter.api.Test;
-
-import static org.assertj.core.api.Assertions.assertThat;
 
 /**
- * Tests for {@link Markdown}.
+ * Model for a Docker Compose file.
  *
  * @author Moritz Halbritter
+ * @author Stephane Nicoll
  */
-class MarkdownTests {
+public class ComposeFile {
 
-	@Test
+	private final ComposeServiceContainer services = new ComposeServiceContainer();
-	void shouldFormatCode() {
-		String code = Markdown.code("c = a + b");
-		assertThat(code).isEqualTo("`c = a + b`");
-	}
 
-	@Test
+	/**
-	void shouldFormatLink() {
+	 * Return the {@linkplain ComposeServiceContainer service container} to use to
-		String link = Markdown.link("Spring Website", "https://spring.io/");
+	 * configure services.
-		assertThat(link).isEqualTo("[Spring Website](https://spring.io/)");
+	 * @return the {@link ComposeServiceContainer}
+	 */
+	public ComposeServiceContainer services() {
+		return this.services;
 	}
 
 }

initializr-generator/src/main/java/io/spring/initializr/generator/container/docker/compose/ComposeFileWriter.java

@@ -0,0 +1,82 @@
+/*
+ * 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.initializr.generator.container.docker.compose;
+
+import java.util.Comparator;
+import java.util.Map;
+import java.util.Set;
+
+import io.spring.initializr.generator.io.IndentingWriter;
+
+/**
+ * A {@link ComposeFile} writer for {@code compose.yaml}.
+ *
+ * @author Stephane Nicoll
+ * @author Moritz Halbritter
+ */
+public class ComposeFileWriter {
+
+	/**
+	 * Write a {@linkplain ComposeFile compose.yaml} using the specified
+	 * {@linkplain IndentingWriter writer}.
+	 * @param writer the writer to use
+	 * @param compose the compose file to write
+	 */
+	public void writeTo(IndentingWriter writer, ComposeFile compose) {
+		writer.println("services:");
+		compose.services()
+			.values()
+			.sorted(Comparator.comparing(ComposeService::getName))
+			.forEach((service) -> writeService(writer, service));
+	}
+
+	private void writeService(IndentingWriter writer, ComposeService service) {
+		writer.indented(() -> {
+			writer.println(service.getName() + ":");
+			writer.indented(() -> {
+				writer.println("image: '%s:%s'".formatted(service.getImage(), service.getImageTag()));
+				writerServiceEnvironment(writer, service.getEnvironment());
+				writerServicePorts(writer, service.getPorts());
+			});
+		});
+	}
+
+	private void writerServiceEnvironment(IndentingWriter writer, Map<String, String> environment) {
+		if (environment.isEmpty()) {
+			return;
+		}
+		writer.println("environment:");
+		writer.indented(() -> {
+			for (Map.Entry<String, String> env : environment.entrySet()) {
+				writer.println("- '%s=%s'".formatted(env.getKey(), env.getValue()));
+			}
+		});
+	}
+
+	private void writerServicePorts(IndentingWriter writer, Set<Integer> ports) {
+		if (ports.isEmpty()) {
+			return;
+		}
+		writer.println("ports:");
+		writer.indented(() -> {
+			for (Integer port : ports) {
+				writer.println("- '%d'".formatted(port));
+			}
+		});
+	}
+
+}

initializr-generator/src/main/java/io/spring/initializr/generator/container/docker/compose/ComposeService.java

@@ -0,0 +1,151 @@
+/*
+ * 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.initializr.generator.container.docker.compose;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.TreeSet;
+
+/**
+ * A service to be declared in a Docker Compose file.
+ *
+ * @author Moritz Halbritter
+ * @author Stephane Nicoll
+ */
+public final class ComposeService {
+
+	private final String name;
+
+	private final String image;
+
+	private final String imageTag;
+
+	private final String imageWebsite;
+
+	private final Map<String, String> environment;
+
+	private final Set<Integer> ports;
+
+	private ComposeService(Builder builder) {
+		this.name = builder.name;
+		this.image = builder.image;
+		this.imageTag = builder.imageTag;
+		this.imageWebsite = builder.imageWebsite;
+		this.environment = Collections.unmodifiableMap(new TreeMap<>(builder.environment));
+		this.ports = Collections.unmodifiableSet(new TreeSet<>(builder.ports));
+	}
+
+	public String getName() {
+		return this.name;
+	}
+
+	public String getImage() {
+		return this.image;
+	}
+
+	public String getImageTag() {
+		return this.imageTag;
+	}
+
+	public String getImageWebsite() {
+		return this.imageWebsite;
+	}
+
+	public Map<String, String> getEnvironment() {
+		return this.environment;
+	}
+
+	public Set<Integer> getPorts() {
+		return this.ports;
+	}
+
+	/**
+	 * Builder for {@link ComposeService}.
+	 */
+	public static class Builder {
+
+		private final String name;
+
+		private String image;
+
+		private String imageTag = "latest";
+
+		private String imageWebsite;
+
+		private final Map<String, String> environment = new TreeMap<>();
+
+		private final Set<Integer> ports = new TreeSet<>();
+
+		protected Builder(String name) {
+			this.name = name;
+		}
+
+		public Builder imageAndTag(String imageAndTag) {
+			String[] split = imageAndTag.split(":", 2);
+			String tag = (split.length == 1) ? "latest" : split[1];
+			return image(split[0]).imageTag(tag);
+		}
+
+		public Builder image(String image) {
+			this.image = image;
+			return this;
+		}
+
+		public Builder imageTag(String imageTag) {
+			this.imageTag = imageTag;
+			return this;
+		}
+
+		public Builder imageWebsite(String imageWebsite) {
+			this.imageWebsite = imageWebsite;
+			return this;
+		}
+
+		public Builder environment(String key, String value) {
+			this.environment.put(key, value);
+			return this;
+		}
+
+		public Builder environment(Map<String, String> environment) {
+			this.environment.putAll(environment);
+			return this;
+		}
+
+		public Builder ports(Collection<Integer> ports) {
+			this.ports.addAll(ports);
+			return this;
+		}
+
+		public Builder ports(int... ports) {
+			return ports(Arrays.stream(ports).boxed().toList());
+		}
+
+		/**
+		 * Builds the {@link ComposeService} instance.
+		 * @return the built instance
+		 */
+		public ComposeService build() {
+			return new ComposeService(this);
+		}
+
+	}
+
+}

initializr-generator/src/main/java/io/spring/initializr/generator/container/docker/compose/ComposeServiceContainer.java

@@ -0,0 +1,82 @@
+/*
+ * 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.initializr.generator.container.docker.compose;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.function.Consumer;
+import java.util.stream.Stream;
+
+import io.spring.initializr.generator.container.docker.compose.ComposeService.Builder;
+
+/**
+ * A container for {@linkplain ComposeService Docker Compose services}.
+ *
+ * @author Stephane Nicoll
+ */
+public class ComposeServiceContainer {
+
+	private final Map<String, Builder> services = new LinkedHashMap<>();
+
+	/**
+	 * Specify if this container is empty.
+	 * @return {@code true} if no service is registered
+	 */
+	public boolean isEmpty() {
+		return this.services.isEmpty();
+	}
+
+	/**
+	 * Specify if this container has a service customization with the specified
+	 * {@code name}.
+	 * @param name the name of a service
+	 * @return {@code true} if a customization for a service with the specified
+	 * {@code name} exists
+	 */
+	public boolean has(String name) {
+		return this.services.containsKey(name);
+	}
+
+	/**
+	 * Return the {@link ComposeService services} to customize.
+	 * @return the compose services
+	 */
+	public Stream<ComposeService> values() {
+		return this.services.values().stream().map(Builder::build);
+	}
+
+	/**
+	 * Add a {@link ComposeService} with the specified name and {@link Consumer} to
+	 * customize the object. If the service has already been added, the consumer can be
+	 * used to further tune the existing service configuration.
+	 * @param name the name of the service
+	 * @param service a {@link Consumer} to customize the {@link ComposeService}
+	 */
+	public void add(String name, Consumer<Builder> service) {
+		service.accept(this.services.computeIfAbsent(name, Builder::new));
+	}
+
+	/**
+	 * Remove the service with the specified {@code name}.
+	 * @param name the name of the service
+	 * @return {@code true} if such a service was registered, {@code false} otherwise
+	 */
+	public boolean remove(String name) {
+		return this.services.remove(name) != null;
+	}
+
+}

initializr-generator/src/main/java/io/spring/initializr/generator/container/docker/compose/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * 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.
+ */
+
+/**
+ * Docker Compose support.
+ */
+package io.spring.initializr.generator.container.docker.compose;

initializr-generator/src/test/java/io/spring/initializr/generator/container/docker/compose/ComposeFileWriterTests.java

@@ -0,0 +1,99 @@
+/*
+ * 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.initializr.generator.container.docker.compose;
+
+import java.io.StringWriter;
+import java.util.function.Consumer;
+
+import io.spring.initializr.generator.container.docker.compose.ComposeService.Builder;
+import io.spring.initializr.generator.io.IndentingWriter;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link ComposeFile}.
+ *
+ * @author Moritz Halbritter
+ * @author Stephane Nicoll
+ */
+class ComposeFileWriterTests {
+
+	@Test
+	void writeBasicServices() {
+		ComposeFile file = new ComposeFile();
+		file.services().add("first", withSuffix(1));
+		file.services().add("second", withSuffix(2));
+		assertThat(write(file)).isEqualToIgnoringNewLines("""
+				services:
+					first:
+						image: 'image-1:image-tag-1'
+					second:
+						image: 'image-2:image-tag-2'
+				""");
+	}
+
+	@Test
+	void writeDetailedService() {
+		ComposeFile file = new ComposeFile();
+		file.services()
+			.add("elasticsearch",
+					(builder) -> builder.image("elasticsearch")
+						.imageTag("8.6.1")
+						.imageWebsite("https://www.docker.elastic.co/r/elasticsearch")
+						.environment("ELASTIC_PASSWORD", "secret")
+						.environment("discovery.type", "single-node")
+						.ports(9200, 9300));
+		assertThat(write(file)).isEqualToIgnoringNewLines("""
+				services:
+					elasticsearch:
+						image: 'elasticsearch:8.6.1'
+						environment:
+							- 'ELASTIC_PASSWORD=secret'
+							- 'discovery.type=single-node'
+						ports:
+							- '9200'
+							- '9300'
+				""");
+	}
+
+	@Test
+	void servicesAreOrderedByName() {
+		ComposeFile file = new ComposeFile();
+		file.services().add("b", withSuffix(2));
+		file.services().add("a", withSuffix(1));
+		assertThat(write(file)).isEqualToIgnoringNewLines("""
+				services:
+					a:
+						image: 'image-1:image-tag-1'
+					b:
+						image: 'image-2:image-tag-2'
+				""");
+	}
+
+	private Consumer<Builder> withSuffix(int suffix) {
+		return (builder) -> builder.image("image-" + suffix).imageTag("image-tag-" + suffix);
+	}
+
+	private String write(ComposeFile file) {
+		StringWriter out = new StringWriter();
+		IndentingWriter writer = new IndentingWriter(out, "\t"::repeat);
+		new ComposeFileWriter().writeTo(writer, file);
+		return out.toString();
+	}
+
+}

initializr-generator/src/test/java/io/spring/initializr/generator/container/docker/compose/ComposeServiceContainerTests.java

@@ -0,0 +1,182 @@
+/*
+ * 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.initializr.generator.container.docker.compose;
+
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
+
+/**
+ * Tests for {@link ComposeServiceContainer}.
+ *
+ * @author Stephane Nicoll
+ */
+class ComposeServiceContainerTests {
+
+	@Test
+	void isEmptyWithEmptyContainer() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		assertThat(container.isEmpty()).isTrue();
+	}
+
+	@Test
+	void isEmptyWithService() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> service.image("my-image"));
+		assertThat(container.isEmpty()).isFalse();
+	}
+
+	@Test
+	void hasWithMatchingService() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> service.image("my-image"));
+		assertThat(container.has("test")).isTrue();
+	}
+
+	@Test
+	void hasWithNonMatchingName() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> service.image("my-image"));
+		assertThat(container.has("another")).isFalse();
+	}
+
+	@Test
+	void tagIsSetToLatestIfNotGiven() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> service.image("my-image"));
+		assertThat(container.values()).singleElement().satisfies((service) -> {
+			assertThat(service.getImage()).isEqualTo("my-image");
+			assertThat(service.getImageTag()).isEqualTo("latest");
+		});
+	}
+
+	@Test
+	void tagIsSetToLatestIfNotGivenInImageTag() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> service.imageAndTag("my-image"));
+		assertThat(container.values()).singleElement().satisfies((service) -> {
+			assertThat(service.getImage()).isEqualTo("my-image");
+			assertThat(service.getImageTag()).isEqualTo("latest");
+		});
+	}
+
+	@Test
+	void tagIsSetToGivenInImageTag() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> service.imageAndTag("my-image:1.2.3"));
+		assertThat(container.values()).singleElement().satisfies((service) -> {
+			assertThat(service.getImage()).isEqualTo("my-image");
+			assertThat(service.getImageTag()).isEqualTo("1.2.3");
+		});
+	}
+
+	@Test
+	void portsAreSorted() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> service.imageAndTag("my-image").ports(8080));
+		container.add("test", (service) -> service.ports(7070));
+		assertThat(container.values()).singleElement()
+			.satisfies((service) -> assertThat(service.getPorts()).containsExactly(7070, 8080));
+	}
+
+	@Test
+	void environmentKeysAreSorted() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> service.imageAndTag("my-image").environment("z", "zz"));
+		container.add("test", (service) -> service.environment("a", "aa"));
+		assertThat(container.values()).singleElement()
+			.satisfies((service) -> assertThat(service.getEnvironment()).containsExactly(entry("a", "aa"),
+					entry("z", "zz")));
+	}
+
+	@Test
+	void environmentIsMerged() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> service.imageAndTag("my-image").environment(Map.of("a", "aa", "z", "zz")));
+		container.add("test", (service) -> service.environment(Map.of("a", "aaa", "b", "bb")));
+		assertThat(container.values()).singleElement()
+			.satisfies((service) -> assertThat(service.getEnvironment()).containsExactly(entry("a", "aaa"),
+					entry("b", "bb"), entry("z", "zz")));
+	}
+
+	@Test
+	void customizeService() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> {
+			service.image("my-image");
+			service.imageTag("my-image-tag");
+			service.imageWebsite("https://example.com/my-image");
+			service.environment("param", "value");
+			service.ports(8080);
+		});
+		assertThat(container.values()).singleElement().satisfies((service) -> {
+			assertThat(service.getName()).isEqualTo("test");
+			assertThat(service.getImage()).isEqualTo("my-image");
+			assertThat(service.getImageTag()).isEqualTo("my-image-tag");
+			assertThat(service.getImageWebsite()).isEqualTo("https://example.com/my-image");
+			assertThat(service.getEnvironment()).containsOnly(entry("param", "value"));
+			assertThat(service.getPorts()).containsOnly(8080);
+		});
+	}
+
+	@Test
+	void customizeTaskSeveralTimeReuseConfiguration() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> {
+			service.image("my-image");
+			service.imageTag("my-image-tag");
+			service.imageWebsite("https://example.com/my-image");
+			service.environment("param", "value");
+			service.ports(7070);
+		});
+		container.add("test", (service) -> {
+			service.image("my-image");
+			service.imageTag("my-image-tag");
+			service.imageWebsite("https://example.com/my-image");
+			service.environment("param", "value2");
+			service.ports(8080);
+		});
+		assertThat(container.values()).singleElement().satisfies((service) -> {
+			assertThat(service.getName()).isEqualTo("test");
+			assertThat(service.getImage()).isEqualTo("my-image");
+			assertThat(service.getImageTag()).isEqualTo("my-image-tag");
+			assertThat(service.getImageWebsite()).isEqualTo("https://example.com/my-image");
+			assertThat(service.getEnvironment()).containsOnly(entry("param", "value2"));
+			assertThat(service.getPorts()).containsOnly(7070, 8080);
+		});
+	}
+
+	@Test
+	void removeWithMatchingService() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> service.image("my-image"));
+		assertThat(container.remove("test")).isTrue();
+		assertThat(container.isEmpty()).isTrue();
+	}
+
+	@Test
+	void removeWithNonMatchingName() {
+		ComposeServiceContainer container = new ComposeServiceContainer();
+		container.add("test", (service) -> service.image("my-image"));
+		assertThat(container.remove("another")).isFalse();
+		assertThat(container.isEmpty()).isFalse();
+	}
+
+}

initializr-web/src/main/java/io/spring/initializr/web/autoconfigure/InitializrAutoConfiguration.java

@@ -87,7 +87,8 @@ public class InitializrAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean
 	public IndentingWriterFactory indentingWriterFactory() {
-		return IndentingWriterFactory.create(new SimpleIndentStrategy("\t"));
+		return IndentingWriterFactory.create(new SimpleIndentStrategy("\t"),
+				(builder) -> builder.indentingStrategy("yaml", new SimpleIndentStrategy("  ")));
 	}
 
 	@Bean

src/checkstyle/checkstyle-suppressions.xml

@@ -6,6 +6,4 @@
 	<suppress files=".+Application\.java" checks="HideUtilityClassConstructor"/>
 	<suppress files="[\\/]initializr-service-sample[\\/]" checks="JavadocType"/>
 	<suppress files="[\\/]initializr-service-sample[\\/]" checks="ImportControl"/>
-	<suppress files="initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeServiceTests.java" checks="SpringLeadingWhitespace"/>
-	<suppress files="initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/container/dockercompose/DockerComposeFileTests." checks="SpringLeadingWhitespace"/>
 </suppressions>