feat(jib): support building images from scratch

Signed-off-by: Marc Nuri <[email protected]>

Author: manusa

jkube-kit/build/service/jib/src/main/java/org/eclipse/jkube/kit/service/jib/JibServiceUtil.java

@@ -22,6 +22,7 @@
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
 
+import com.google.cloud.tools.jib.api.ImageReference;
 import org.eclipse.jkube.kit.build.api.assembly.BuildDirs;
 import org.eclipse.jkube.kit.common.Assembly;
 import org.eclipse.jkube.kit.common.AssemblyFileEntry;
@@ -54,10 +55,16 @@ private JibServiceUtil() {
   private static final String BUSYBOX = "busybox:latest";
 
   public static JibContainerBuilder containerFromImageConfiguration(
-    ImageConfiguration imageConfiguration, String pullRegistry, Credential pullRegistryCredential) {
-    final JibContainerBuilder containerBuilder = Jib
-      .from(toRegistryImage(getBaseImage(imageConfiguration, pullRegistry), pullRegistryCredential))
-      .setFormat(ImageFormat.Docker);
+    ImageConfiguration imageConfiguration, String pullRegistry, Credential pullRegistryCredential
+  ) {
+    final String baseImage = getBaseImage(imageConfiguration, pullRegistry);
+    final JibContainerBuilder containerBuilder;
+    if (baseImage.equals(ImageReference.scratch().toString() + ":latest")) {
+      containerBuilder = Jib.fromScratch();
+    } else {
+      containerBuilder = Jib.from(toRegistryImage(baseImage, pullRegistryCredential));
+    }
+    containerBuilder.setFormat(ImageFormat.Docker);
     if (imageConfiguration.getBuildConfiguration() != null) {
       final BuildConfiguration bic = imageConfiguration.getBuildConfiguration();
       Optional.ofNullable(bic.getEntryPoint())

jkube-kit/build/service/jib/src/test/java/org/eclipse/jkube/kit/service/jib/JibServiceTest.java

@@ -114,15 +114,6 @@ void prependsRegistryWhenNotConfiguredInName() throws Exception {
   @DisplayName("build")
   class Build {
 
-    @BeforeEach
-    void setUp() {
-      imageConfiguration = imageConfiguration.toBuilder()
-        .build(imageConfiguration.getBuild().toBuilder()
-          .from("gcr.io/distroless/base@sha256:8267a5d9fa15a538227a8850e81cf6c548a78de73458e99a67e8799bbffb1ba0")
-          .build())
-        .build();
-    }
-
     @Test
     void build() throws Exception {
       try (JibService jibService = new JibService(jibLogger, testAuthConfigFactory, configuration, imageConfiguration)) {