Add cache methods for writing/reading local base image container config

jib-core/src/main/java/com/google/cloud/tools/jib/cache/Cache.java

@@ -130,6 +130,25 @@ public CachedLayer writeTarLayer(DescriptorDigest diffId, Blob compressedBlob)
     return cacheStorageWriter.writeTarLayer(diffId, compressedBlob);
   }
 
+  /**
+   * Writes a container configuration to {@code (cache directory)/local/config/(image id)}. An image
+   * ID is a SHA hash of a container configuration JSON. The value is also shown as IMAGE ID in
+   * {@code docker images}.
+   *
+   * <p>Note: the {@code imageID} to the {@code containerConfiguration} is a one-way relationship;
+   * there is no guarantee that {@code containerConfiguration}'s SHA will be {@code imageID}, since
+   * the original container configuration is being rewritten here rather than being moved.
+   *
+   * @param imageId the ID of the image to store the container configuration for
+   * @param containerConfiguration the container configuration
+   * @throws IOException if an I/O exception occurs
+   */
+  void writeLocalConfig(
+      DescriptorDigest imageId, ContainerConfigurationTemplate containerConfiguration)
+      throws IOException {
+    cacheStorageWriter.writeLocalConfig(imageId, containerConfiguration);
+  }
+
   /**
    * Retrieves the cached manifest and container configuration for an image reference.
    *
@@ -187,4 +206,23 @@ public Optional<CachedLayer> retrieveTarLayer(DescriptorDigest diffId)
       throws IOException, CacheCorruptedException {
     return cacheStorageReader.retrieveTarLayer(diffId);
   }
+
+  /**
+   * Retrieves the {@link ContainerConfigurationTemplate} for the image saved from the given image
+   * ID. An image ID is a SHA hash of a container configuration JSON. The value is also shown as
+   * IMAGE ID in {@code docker images}.
+   *
+   * <p>Note: the {@code imageID} is only used to find the {@code containerConfiguration}, and is
+   * not necessarily the actual SHA of {@code containerConfiguration}. There is no guarantee that
+   * {@code containerConfiguration}'s SHA will be {@code imageID}, since the saved container
+   * configuration is not a direct copy of the base image's original configuration.
+   *
+   * @param imageId the image ID
+   * @return the {@link ContainerConfigurationTemplate} referenced by the image ID, if found
+   * @throws IOException if an I/O exception occurs
+   */
+  public Optional<ContainerConfigurationTemplate> retrieveLocalConfig(DescriptorDigest imageId)
+      throws IOException {
+    return cacheStorageReader.retrieveLocalConfig(imageId);
+  }
 }

jib-core/src/main/java/com/google/cloud/tools/jib/cache/CacheStorageReader.java

@@ -223,6 +223,26 @@ Optional<CachedLayer> retrieveTarLayer(DescriptorDigest diffId)
     }
   }
 
+  /**
+   * Retrieves the {@link ContainerConfigurationTemplate} for the image with the given image ID.
+   *
+   * @param imageId the image ID
+   * @return the {@link ContainerConfigurationTemplate} referenced by the image ID, if found
+   * @throws IOException if an I/O exception occurs
+   */
+  Optional<ContainerConfigurationTemplate> retrieveLocalConfig(DescriptorDigest imageId)
+      throws IOException {
+    Path configPath =
+        cacheStorageFiles.getLocalDirectory().resolve("config").resolve(imageId.getHash());
+    if (!Files.exists(configPath)) {
+      return Optional.empty();
+    }
+
+    ContainerConfigurationTemplate config =
+        JsonTemplateMapper.readJsonFromFile(configPath, ContainerConfigurationTemplate.class);
+    return Optional.of(config);
+  }
+
   /**
    * Retrieves the layer digest selected by the {@code selector}.
    *

jib-core/src/main/java/com/google/cloud/tools/jib/cache/CacheStorageWriter.java

@@ -332,6 +332,21 @@ void writeMetadata(ImageReference imageReference, V21ManifestTemplate manifestTe
     }
   }
 
+  /**
+   * Writes a container configuration to {@code (cache directory)/local/config/(image id)}.
+   *
+   * @param imageId the ID of the image to store the container configuration for
+   * @param containerConfiguration the container configuration
+   * @throws IOException if an I/O exception occurs
+   */
+  void writeLocalConfig(
+      DescriptorDigest imageId, ContainerConfigurationTemplate containerConfiguration)
+      throws IOException {
+    Path configDirectory = cacheStorageFiles.getLocalDirectory().resolve("config");
+    Files.createDirectories(configDirectory);
+    writeMetadata(containerConfiguration, configDirectory.resolve(imageId.getHash()));
+  }
+
   /**
    * Writes a compressed {@code layerBlob} to the {@code layerDirectory}.
    *

jib-core/src/test/java/com/google/cloud/tools/jib/cache/CacheStorageReaderTest.java

@@ -248,6 +248,35 @@ public void testRetrieveTarLayer() throws IOException, CacheCorruptedException {
     }
   }
 
+  @Test
+  public void testRetrieveLocalConfig() throws IOException, URISyntaxException, DigestException {
+    Path cacheDirectory = temporaryFolder.newFolder().toPath();
+    Path configDirectory = cacheDirectory.resolve("local").resolve("config");
+    Files.createDirectories(configDirectory);
+    Files.copy(
+        Paths.get(Resources.getResource("core/json/containerconfig.json").toURI()),
+        configDirectory.resolve(
+            "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"));
+
+    CacheStorageFiles cacheStorageFiles = new CacheStorageFiles(cacheDirectory);
+    CacheStorageReader cacheStorageReader = new CacheStorageReader(cacheStorageFiles);
+
+    ContainerConfigurationTemplate configurationTemplate =
+        cacheStorageReader
+            .retrieveLocalConfig(
+                DescriptorDigest.fromHash(
+                    "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"))
+            .get();
+    Assert.assertEquals("wasm", configurationTemplate.getArchitecture());
+    Assert.assertEquals("js", configurationTemplate.getOs());
+
+    Optional<ContainerConfigurationTemplate> missingConfigurationTemplate =
+        cacheStorageReader.retrieveLocalConfig(
+            DescriptorDigest.fromHash(
+                "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"));
+    Assert.assertFalse(missingConfigurationTemplate.isPresent());
+  }
+
   @Test
   public void testSelect_invalidLayerDigest() throws IOException {
     CacheStorageFiles cacheStorageFiles =

jib-core/src/test/java/com/google/cloud/tools/jib/cache/CacheStorageWriterTest.java

@@ -34,6 +34,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.security.DigestException;
 import java.util.zip.GZIPInputStream;
 import java.util.zip.GZIPOutputStream;
 import org.junit.Assert;
@@ -185,6 +186,32 @@ public void testWriteMetadata_v22()
     Assert.assertEquals("wasm", savedContainerConfig.getArchitecture());
   }
 
+  @Test
+  public void testWriteLocalConfig() throws IOException, URISyntaxException, DigestException {
+    Path containerConfigurationJsonFile =
+        Paths.get(
+            getClass().getClassLoader().getResource("core/json/containerconfig.json").toURI());
+    ContainerConfigurationTemplate containerConfigurationTemplate =
+        JsonTemplateMapper.readJsonFromFile(
+            containerConfigurationJsonFile, ContainerConfigurationTemplate.class);
+
+    new CacheStorageWriter(cacheStorageFiles)
+        .writeLocalConfig(
+            DescriptorDigest.fromHash(
+                "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+            containerConfigurationTemplate);
+
+    Path savedConfigPath =
+        cacheStorageFiles
+            .getLocalDirectory()
+            .resolve("config")
+            .resolve("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
+    Assert.assertTrue(Files.exists(savedConfigPath));
+    ContainerConfigurationTemplate savedContainerConfig =
+        JsonTemplateMapper.readJsonFromFile(savedConfigPath, ContainerConfigurationTemplate.class);
+    Assert.assertEquals("wasm", savedContainerConfig.getArchitecture());
+  }
+
   private void verifyCachedLayer(CachedLayer cachedLayer, Blob uncompressedLayerBlob)
       throws IOException {
     BlobDescriptor layerBlobDescriptor = getDigest(compress(uncompressedLayerBlob));