Create helper for parsing an error code from error response

jib-core/src/main/java/com/google/cloud/tools/jib/registry/BlobChecker.java

@@ -23,10 +23,6 @@
 import com.google.cloud.tools.jib.http.BlobHttpContent;
 import com.google.cloud.tools.jib.http.Response;
 import com.google.cloud.tools.jib.image.DescriptorDigest;
-import com.google.cloud.tools.jib.json.JsonTemplateMapper;
-import com.google.cloud.tools.jib.registry.json.ErrorEntryTemplate;
-import com.google.cloud.tools.jib.registry.json.ErrorResponseTemplate;
-import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.Collections;
@@ -71,34 +67,15 @@ public BlobDescriptor handleHttpResponseException(HttpResponseException httpResp
     }
 
     // Finds a BLOB_UNKNOWN error response code.
-    String errorContent = httpResponseException.getContent();
-    if (errorContent == null) {
+    if (httpResponseException.getContent() == null) {
       // TODO: The Google HTTP client gives null content for HEAD requests. Make the content never
       // be null, even for HEAD requests.
       return null;
+    }
 
-    } else {
-      try {
-        ErrorResponseTemplate errorResponse =
-            JsonTemplateMapper.readJson(errorContent, ErrorResponseTemplate.class);
-        List<ErrorEntryTemplate> errors = errorResponse.getErrors();
-        if (errors.size() == 1) {
-          String errorCodeString = errors.get(0).getCode();
-          if (errorCodeString == null) {
-            // Did not get an error code back.
-            throw httpResponseException;
-          }
-          ErrorCodes errorCode = ErrorCodes.valueOf(errorCodeString);
-          if (errorCode.equals(ErrorCodes.BLOB_UNKNOWN)) {
-            return null;
-          }
-        }
-
-      } catch (IOException ex) {
-        throw new RegistryErrorExceptionBuilder(getActionDescription(), ex)
-            .addReason("Failed to parse registry error response body")
-            .build();
-      }
+    ErrorCodes errorCode = ErrorResponseUtil.getErrorCode(httpResponseException);
+    if (errorCode == ErrorCodes.BLOB_UNKNOWN) {
+      return null;
     }
 
     // BLOB_UNKNOWN was not found as a error response code.

jib-core/src/main/java/com/google/cloud/tools/jib/registry/ErrorResponseUtil.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * 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
+ *
+ *    http://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 com.google.cloud.tools.jib.registry;
+
+import com.google.api.client.http.HttpResponseException;
+import com.google.cloud.tools.jib.json.JsonTemplateMapper;
+import com.google.cloud.tools.jib.registry.json.ErrorEntryTemplate;
+import com.google.cloud.tools.jib.registry.json.ErrorResponseTemplate;
+import java.io.IOException;
+import java.util.List;
+
+/** Utility methods for parsing {@link ErrorResponseTemplate JSON-encoded error responses}. */
+public class ErrorResponseUtil {
+
+  /**
+   * Extract an {@link ErrorCodes} response from the error object encoded in an {@link
+   * HttpResponseException}.
+   *
+   * @param httpResponseException the response exception
+   * @return the parsed {@link ErrorCodes} if found
+   * @throws HttpResponseException rethrows the original exception if an error object could not be
+   *     parsed, if there were multiple error objects, or if the error code is unknown.
+   */
+  public static ErrorCodes getErrorCode(HttpResponseException httpResponseException)
+      throws HttpResponseException {
+    // Obtain the error response code.
+    String errorContent = httpResponseException.getContent();
+    if (errorContent == null) {
+      throw httpResponseException;
+    }
+
+    try {
+      ErrorResponseTemplate errorResponse =
+          JsonTemplateMapper.readJson(errorContent, ErrorResponseTemplate.class);
+      List<ErrorEntryTemplate> errors = errorResponse.getErrors();
+      // There may be multiple error objects
+      if (errors.size() == 1) {
+        String errorCodeString = errors.get(0).getCode();
+        // May not get an error code back.
+        if (errorCodeString != null) {
+          // throws IllegalArgumentException if unknown error code
+          return ErrorCodes.valueOf(errorCodeString);
+        }
+      }
+
+    } catch (IOException | IllegalArgumentException ex) {
+      // Parse exception: either isn't an error object or unknown error code
+    }
+
+    // rethrow the original exception
+    throw httpResponseException;
+  }
+
+  // not intended to be instantiated
+  private ErrorResponseUtil() {}
+}

jib-core/src/main/java/com/google/cloud/tools/jib/registry/ManifestPusher.java

@@ -22,9 +22,6 @@
 import com.google.cloud.tools.jib.http.Response;
 import com.google.cloud.tools.jib.image.json.BuildableManifestTemplate;
 import com.google.cloud.tools.jib.json.JsonTemplateMapper;
-import com.google.cloud.tools.jib.registry.json.ErrorEntryTemplate;
-import com.google.cloud.tools.jib.registry.json.ErrorResponseTemplate;
-import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.Collections;
@@ -77,40 +74,13 @@ public Void handleHttpResponseException(HttpResponseException httpResponseExcept
       throw httpResponseException;
     }
 
-    // TODO turn deserializing the error-code into a library method
-
-    // Obtain the error response code.
-    String errorContent = httpResponseException.getContent();
-    if (errorContent == null) {
-      throw httpResponseException;
-    }
-
-    try {
-      ErrorResponseTemplate errorResponse =
-          JsonTemplateMapper.readJson(errorContent, ErrorResponseTemplate.class);
-      List<ErrorEntryTemplate> errors = errorResponse.getErrors();
-      if (errors.size() == 1) {
-        String errorCodeString = errors.get(0).getCode();
-        if (errorCodeString == null) {
-          // Did not get an error code back.
-          throw httpResponseException;
-        }
-        ErrorCodes errorCode = ErrorCodes.valueOf(errorCodeString);
-        if (errorCode.equals(ErrorCodes.MANIFEST_INVALID)
-            || errorCode.equals(ErrorCodes.TAG_INVALID)) {
-          throw new RegistryErrorExceptionBuilder(getActionDescription(), httpResponseException)
-              .addReason("Registry may not support Image Manifest Version 2, Schema 2")
-              .build();
-        }
-      }
-
-    } catch (IOException ex) {
+    ErrorCodes errorCode = ErrorResponseUtil.getErrorCode(httpResponseException);
+    if (errorCode == ErrorCodes.MANIFEST_INVALID || errorCode == ErrorCodes.TAG_INVALID) {
       throw new RegistryErrorExceptionBuilder(getActionDescription(), httpResponseException)
-          .addReason("Failed to parse registry error response body")
+          .addReason("Registry may not support Image Manifest Version 2, Schema 2")
           .build();
     }
-
-    // unhandled error response code.
+    // rethrow: unhandled error response code.
     throw httpResponseException;
   }
 

jib-core/src/test/java/com/google/cloud/tools/jib/registry/ErrorResponseUtilTest.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * 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
+ *
+ *    http://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 com.google.cloud.tools.jib.registry;
+
+import com.google.api.client.http.HttpHeaders;
+import com.google.api.client.http.HttpResponseException;
+import org.apache.http.HttpStatus;
+import org.junit.Assert;
+import org.junit.Test;
+
+/** Test for {@link ErrorReponseUtil}. */
+public class ErrorResponseUtilTest {
+
+  @Test
+  public void testGetErrorCode_knownErrorCode() throws HttpResponseException {
+    HttpResponseException httpResponseException =
+        new HttpResponseException.Builder(
+                HttpStatus.SC_BAD_REQUEST, "Bad Request", new HttpHeaders())
+            .setContent(
+                "{\"errors\":[{\"code\":\"MANIFEST_INVALID\",\"message\":\"manifest invalid\",\"detail\":{}}]}")
+            .build();
+
+    Assert.assertSame(
+        ErrorCodes.MANIFEST_INVALID, ErrorResponseUtil.getErrorCode(httpResponseException));
+  }
+
+  /** An unknown {@link ErrorCodes} should cause original exception to be rethrown. */
+  @Test
+  public void testGetErrorCode_unknownErrorCode() {
+    HttpResponseException httpResponseException =
+        new HttpResponseException.Builder(
+                HttpStatus.SC_BAD_REQUEST, "Bad Request", new HttpHeaders())
+            .setContent(
+                "{\"errors\":[{\"code\":\"INVALID_ERROR_CODE\",\"message\":\"invalid code\",\"detail\":{}}]}")
+            .build();
+    try {
+      ErrorResponseUtil.getErrorCode(httpResponseException);
+      Assert.fail();
+    } catch (HttpResponseException ex) {
+      Assert.assertSame(httpResponseException, ex);
+    }
+  }
+
+  /** Multiple error objects should cause original exception to be rethrown. */
+  @Test
+  public void testGetErrorCode_multipleErrors() {
+    HttpResponseException httpResponseException =
+        new HttpResponseException.Builder(
+                HttpStatus.SC_BAD_REQUEST, "Bad Request", new HttpHeaders())
+            .setContent(
+                "{\"errors\":["
+                    + "{\"code\":\"MANIFEST_INVALID\",\"message\":\"message 1\",\"detail\":{}},"
+                    + "{\"code\":\"TAG_INVALID\",\"message\":\"message 2\",\"detail\":{}}"
+                    + "]}")
+            .build();
+    try {
+      ErrorResponseUtil.getErrorCode(httpResponseException);
+      Assert.fail();
+    } catch (HttpResponseException ex) {
+      Assert.assertSame(httpResponseException, ex);
+    }
+  }
+
+  /** An non-error object should cause original exception to be rethrown. */
+  @Test
+  public void testGetErrorCode_invalidErrorObject() {
+    HttpResponseException httpResponseException =
+        new HttpResponseException.Builder(
+                HttpStatus.SC_BAD_REQUEST, "Bad Request", new HttpHeaders())
+            .setContent("{\"type\":\"other\",\"message\":\"some other object\"}")
+            .build();
+    try {
+      ErrorResponseUtil.getErrorCode(httpResponseException);
+      Assert.fail();
+    } catch (HttpResponseException ex) {
+      Assert.assertSame(httpResponseException, ex);
+    }
+  }
+}