feat(gax): add getErrorInfoList to ErrorDetails

Author: westarle

gax-java/gax/src/main/java/com/google/api/gax/rpc/ErrorDetails.java

@@ -44,6 +44,8 @@
 import com.google.rpc.RequestInfo;
 import com.google.rpc.ResourceInfo;
 import com.google.rpc.RetryInfo;
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import javax.annotation.Nullable;
 
@@ -60,6 +62,14 @@ public ErrorInfo getErrorInfo() {
     return unpack(ErrorInfo.class);
   }
 
+  /**
+   * This returns all occurrences of ErrorInfo. A single error response may contain multiple
+   * ErrorInfo messages.
+   */
+  public List<ErrorInfo> getErrorInfoList() {
+    return unpackList(ErrorInfo.class);
+  }
+
   /**
    * Describes when the clients can retry a failed request. Clients could ignore the recommendation
    * here or retry when this information is missing from error responses.
@@ -172,4 +182,26 @@ <T extends Message> T unpack(Class<T> errorTypeClazz) {
     }
     return null;
   }
+
+  @VisibleForTesting
+  <T extends Message> List<T> unpackList(Class<T> errorTypeClazz) {
+    List<Any> rawErrorMessages = getRawErrorMessages();
+    if (rawErrorMessages == null) {
+      return Collections.emptyList();
+    }
+    List<T> unpackedMessages = new ArrayList<>();
+    for (Any detail : rawErrorMessages) {
+      if (detail.is(errorTypeClazz)) {
+        try {
+          unpackedMessages.add(detail.unpack(errorTypeClazz));
+        } catch (InvalidProtocolBufferException e) {
+          throw new ProtocolBufferParsingException(
+              String.format(
+                  "Failed to unpack %s from raw error messages", errorTypeClazz.getSimpleName()),
+              e);
+        }
+      }
+    }
+    return Collections.unmodifiableList(unpackedMessages);
+  }
 }

gax-java/gax/src/test/java/com/google/api/gax/rpc/ErrorDetailsTest.java

@@ -188,6 +188,28 @@ void errorInfo_shouldUnpackErrorInfoProtoMessage() {
     Truth.assertThat(errorDetails.getErrorInfo()).isEqualTo(ERROR_INFO);
   }
 
+  @Test
+  void unpackList_shouldReturnEmptyListIfRawErrorMessagesIsNull() {
+    errorDetails = ErrorDetails.builder().setRawErrorMessages(null).build();
+    Truth.assertThat(errorDetails.unpackList(ErrorInfo.class)).isEmpty();
+  }
+
+  @Test
+  void getErrorInfoList_shouldUnpackAllErrorInfoProtoMessages() {
+    ErrorInfo errorInfo2 =
+        ErrorInfo.newBuilder().setDomain("googleapis.com").setReason("ANOTHER_REASON").build();
+
+    errorDetails =
+        ErrorDetails.builder()
+            .setRawErrorMessages(
+                ImmutableList.of(Any.pack(ERROR_INFO), Any.pack(DEBUG_INFO), Any.pack(errorInfo2)))
+            .build();
+
+    Truth.assertThat(errorDetails.getErrorInfoList())
+        .containsExactly(ERROR_INFO, errorInfo2)
+        .inOrder();
+  }
+
   @Test
   void retryInfo_shouldUnpackRetryInfoProtoMessage() {
     Truth.assertThat(errorDetails.getRetryInfo()).isEqualTo(RETRY_INFO);