Add network option for image building

This commit adds configuration to the Maven and Gradle plugins to
allow specifying the network mode to be provided to the image
building goal and task.

See gh-27486

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/docs/asciidoc/packaging-oci-image.adoc

@@ -176,6 +176,14 @@ Where `<options>` can contain:
 (`spring-boot.build-image.publish`)
 | Whether to publish the generated image to a Docker registry.
 | `false`
+
+| `network` +
+(`spring-boot.build-image.network`)
+| The network the build container will connect to. The value supplied for this option will be passed
+unvalidated as `HostConfig.NetworkMode` to the configuration which creates the build container,
+see https://docs.docker.com/engine/api/v1.41/#operation/ContainerCreate[Docker's engine API].
+Using this option is similar to running `docker build --network ...`.
+|
 |===
 
 NOTE: The plugin detects the target Java compatibility of the project using the compiler's plugin configuration or the `maven.compiler.target` property.

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/BuildImageMojo.java

@@ -59,6 +59,7 @@ import org.springframework.util.StringUtils;
  *
  * @author Phillip Webb
  * @author Scott Frederick
+ * @author Jeroen Meijer
  * @since 2.3.0
  */
 @Mojo(name = "build-image", defaultPhase = LifecyclePhase.PACKAGE, requiresProject = true, threadSafe = true,
@@ -153,6 +154,13 @@ public class BuildImageMojo extends AbstractPackagerMojo {
 	@Parameter(property = "spring-boot.build-image.publish", readonly = true)
 	Boolean publish;
 
+	/**
+	 * Alias for {@link Image#network} to support configuration via command-line property.
+	 * @since 2.6.0
+	 */
+	@Parameter(property = "spring-boot.build-image.network", readonly = true)
+	String network;
+
 	/**
 	 * Docker configuration options.
 	 * @since 2.4.0
@@ -248,6 +256,9 @@ public class BuildImageMojo extends AbstractPackagerMojo {
 		if (image.publish == null && this.publish != null) {
 			image.setPublish(this.publish);
 		}
+		if (image.network == null && this.network != null) {
+			image.setNetwork(this.network);
+		}
 		if (image.publish != null && image.publish && publishRegistryNotConfigured()) {
 			throw new MojoExecutionException("Publishing an image requires docker.publishRegistry to be configured");
 		}

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/Image.java

@@ -39,6 +39,7 @@ import org.springframework.util.StringUtils;
  *
  * @author Phillip Webb
  * @author Scott Frederick
+ * @author Jeroen Meijer
  * @since 2.3.0
  */
 public class Image {
@@ -63,6 +64,8 @@ public class Image {
 
 	List<String> bindings;
 
+	String network;
+
 	/**
 	 * The name of the created image.
 	 * @return the image name
@@ -151,6 +154,18 @@ public class Image {
 		this.publish = publish;
 	}
 
+	/**
+	 * Returns the network the build container will connect to.
+	 * @return the network
+	 */
+	public String getNetwork() {
+		return this.network;
+	}
+
+	public void setNetwork(String network) {
+		this.network = network;
+	}
+
 	BuildRequest getBuildRequest(Artifact artifact, Function<Owner, TarArchive> applicationContent) {
 		return customize(BuildRequest.of(getOrDeduceName(artifact), applicationContent));
 	}
@@ -190,6 +205,7 @@ public class Image {
 		if (!CollectionUtils.isEmpty(this.bindings)) {
 			request = request.withBindings(this.bindings.stream().map(Binding::of).collect(Collectors.toList()));
 		}
+		request = request.withNetwork(this.network);
 		return request;
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/java/org/springframework/boot/maven/ImageTests.java

@@ -41,6 +41,7 @@ import static org.assertj.core.api.Assertions.entry;
  *
  * @author Phillip Webb
  * @author Scott Frederick
+ * @author Jeroen Meijer
  */
 class ImageTests {
 
@@ -70,6 +71,7 @@ class ImageTests {
 		assertThat(request.getPullPolicy()).isEqualTo(PullPolicy.ALWAYS);
 		assertThat(request.getBuildpacks()).isEmpty();
 		assertThat(request.getBindings()).isEmpty();
+		assertThat(request.getNetwork()).isNull();
 	}
 
 	@Test
@@ -146,6 +148,14 @@ class ImageTests {
 				Binding.of("volume-name:container-dest:rw"));
 	}
 
+	@Test
+	void getBuildRequestWhenNetworkUsesNetwork() {
+		Image image = new Image();
+		image.network = "test";
+		BuildRequest request = image.getBuildRequest(createArtifact(), mockApplicationContent());
+		assertThat(request.getNetwork()).isEqualTo("test");
+	}
+
 	private Artifact createArtifact() {
 		return new DefaultArtifact("com.example", "my-app", VersionRange.createFromVersion("0.0.1-SNAPSHOT"), "compile",
 				"jar", null, new DefaultArtifactHandler());