Set ephemeral builder container creation to a fixed date

This commit fixes the `Created` date and time of the ephemeral builder
container image at the Windows epoch plus one second
(1980-01-01T00:00:01Z). This date matches the created date of the builder
image and influences the created date of the resulting image. Using
a fixed date for images ensures that the digest is consistent for all
images with the same version.

Fixes gh-20126

Author: scottfrederick

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/build/EphemeralBuilder.java

@@ -17,8 +17,6 @@
 package org.springframework.boot.buildpack.platform.build;
 
 import java.io.IOException;
-import java.time.Clock;
-import java.time.Instant;
 import java.util.Map;
 
 import org.springframework.boot.buildpack.platform.docker.type.Image;
@@ -55,29 +53,13 @@ class EphemeralBuilder {
 	 */
 	EphemeralBuilder(BuildOwner buildOwner, Image builderImage, BuilderMetadata builderMetadata, Creator creator,
 			Map<String, String> env) throws IOException {
-		this(Clock.systemUTC(), buildOwner, builderImage, builderMetadata, creator, env);
-	}
-
-	/**
-	 * Create a new {@link EphemeralBuilder} instance with a specific clock.
-	 * @param clock the clock used for the current time
-	 * @param buildOwner the build owner
-	 * @param builderImage the image
-	 * @param builderMetadata the builder metadata
-	 * @param creator the builder creator
-	 * @param env the builder env
-	 * @throws IOException on IO error
-	 */
-	EphemeralBuilder(Clock clock, BuildOwner buildOwner, Image builderImage, BuilderMetadata builderMetadata,
-			Creator creator, Map<String, String> env) throws IOException {
 		ImageReference name = ImageReference.random("pack.local/builder/").inTaggedForm();
 		this.buildOwner = buildOwner;
 		this.creator = creator;
 		this.builderMetadata = builderMetadata.copy(this::updateMetadata);
 		this.archive = ImageArchive.from(builderImage, (update) -> {
 			update.withUpdatedConfig(this.builderMetadata::attachTo);
 			update.withTag(name);
-			update.withCreateDate(Instant.now(clock));
 			if (env != null && !env.isEmpty()) {
 				update.withNewLayer(getEnvLayer(env));
 			}

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/type/ImageArchive.java

@@ -21,6 +21,7 @@
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.time.Instant;
+import java.time.OffsetDateTime;
 import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.ArrayList;
@@ -46,13 +47,17 @@
  * An image archive that can be loaded into Docker.
  *
  * @author Phillip Webb
+ * @author Scott Frederick
  * @since 2.3.0
  * @see #from(Image, IOConsumer)
  * @see <a href="https://github.com/moby/moby/blob/master/image/spec/v1.2.md">Docker Image
  * Specification</a>
  */
 public class ImageArchive implements TarArchive {
 
+	private static final Instant WINDOWS_EPOCH_PLUS_SECOND = OffsetDateTime.of(1980, 1, 1, 0, 0, 1, 0, ZoneOffset.UTC)
+			.toInstant();
+
 	private static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ISO_ZONED_DATE_TIME
 			.withZone(ZoneOffset.UTC);
 
@@ -248,7 +253,7 @@ private Update(Image image) {
 
 		private ImageArchive applyTo(IOConsumer<Update> update) throws IOException {
 			update.accept(this);
-			Instant createDate = (this.createDate != null) ? this.createDate : Instant.now();
+			Instant createDate = (this.createDate != null) ? this.createDate : WINDOWS_EPOCH_PLUS_SECOND;
 			return new ImageArchive(SharedObjectMapper.get(), this.config, createDate, this.tag, this.image.getOs(),
 					this.image.getLayers(), Collections.unmodifiableList(this.newLayers));
 		}

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/build/EphemeralBuilderTests.java

@@ -22,9 +22,9 @@
 import java.io.FileOutputStream;
 import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
-import java.time.Clock;
 import java.time.Instant;
-import java.time.ZoneOffset;
+import java.time.OffsetDateTime;
+import java.time.ZoneId;
 import java.util.Collections;
 import java.util.Map;
 
@@ -96,11 +96,16 @@ void getArchiveHasTag() throws Exception {
 	}
 
 	@Test
-	void getArchiveHasCreateDate() throws Exception {
-		Clock clock = Clock.fixed(Instant.now(), ZoneOffset.UTC);
-		EphemeralBuilder builder = new EphemeralBuilder(clock, this.owner, this.image, this.metadata, this.creator,
-				this.env);
-		assertThat(builder.getArchive().getCreateDate()).isEqualTo(Instant.now(clock));
+	void getArchiveHasFixedCreateDate() throws Exception {
+		EphemeralBuilder builder = new EphemeralBuilder(this.owner, this.image, this.metadata, this.creator, this.env);
+		Instant createInstant = builder.getArchive().getCreateDate();
+		OffsetDateTime createDateTime = OffsetDateTime.ofInstant(createInstant, ZoneId.of("UTC"));
+		assertThat(createDateTime.getYear()).isEqualTo(1980);
+		assertThat(createDateTime.getMonthValue()).isEqualTo(1);
+		assertThat(createDateTime.getDayOfMonth()).isEqualTo(1);
+		assertThat(createDateTime.getHour()).isEqualTo(0);
+		assertThat(createDateTime.getMinute()).isEqualTo(0);
+		assertThat(createDateTime.getSecond()).isEqualTo(1);
 	}
 
 	@Test

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/docker/type/ImageArchiveTests.java

@@ -20,9 +20,6 @@
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
-import java.time.Instant;
-import java.time.OffsetDateTime;
-import java.time.ZoneOffset;
 
 import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
 import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
@@ -39,17 +36,15 @@
  * Tests for {@link ImageArchive}.
  *
  * @author Phillip Webb
+ * @author Scott Frederick
  */
 class ImageArchiveTests extends AbstractJsonTests {
 
-	static final Instant CREATE_DATE = OffsetDateTime.of(1906, 12, 9, 11, 30, 0, 0, ZoneOffset.UTC).toInstant();
-
 	@Test
 	void fromImageWritesToValidArchiveTar() throws Exception {
 		Image image = Image.of(getContent("image.json"));
 		ImageArchive archive = ImageArchive.from(image, (update) -> {
 			update.withNewLayer(Layer.of((layout) -> layout.folder("/spring", Owner.ROOT)));
-			update.withCreateDate(CREATE_DATE);
 			update.withTag(ImageReference.of("pack.local/builder/6b7874626575656b6162"));
 		});
 		ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
@@ -78,7 +73,7 @@ private void assertExpectedLayer(TarArchiveEntry entry, byte[] content) throws E
 	}
 
 	private void assertExpectedConfig(TarArchiveEntry entry, byte[] content) throws Exception {
-		assertThat(entry.getName()).isEqualTo("/d1872169d781cff5e1aa22d111f636bef0c57e1c358ca3861e3d33a5bdb1b4a5.json");
+		assertThat(entry.getName()).isEqualTo("/682f8d24b9d9c313d1190a0e955dcb5e65ec9beea40420999839c6f0cbb38382.json");
 		String actualJson = new String(content, StandardCharsets.UTF_8);
 		String expectedJson = StreamUtils.copyToString(getContent("image-archive-config.json"), StandardCharsets.UTF_8);
 		JSONAssert.assertEquals(expectedJson, actualJson, false);

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/resources/org/springframework/boot/buildpack/platform/docker/type/image-archive-config.json

@@ -25,7 +25,7 @@
 			"io.buildpacks.stack.id": "org.cloudfoundry.stacks.cflinuxfs3"
 		}
 	},
-	"created": "1906-12-09T11:30:00Z",
+	"created": "1980-01-01T00:00:01Z",
 	"history": [
 		{
 

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/resources/org/springframework/boot/buildpack/platform/docker/type/image-archive-manifest.json

@@ -1,6 +1,6 @@
 [
 	{
-		"Config": "/d1872169d781cff5e1aa22d111f636bef0c57e1c358ca3861e3d33a5bdb1b4a5.json",
+		"Config": "/682f8d24b9d9c313d1190a0e955dcb5e65ec9beea40420999839c6f0cbb38382.json",
 		"Layers": [
 			"",
 			"",