[v2] S3 200 errors

.changes/next-release/enhancement-s3-70184.json

@@ -0,0 +1,5 @@
+{
+  "type": "enhancement",
+  "category": "``s3``",
+  "description": "Handle HTTP 200 responses with error information for all supported s3 operations."
+}

awscli/botocore/args.py

@@ -157,7 +157,6 @@ def compute_client_args(self, service_model, client_config,
             if raw_value is not None:
                 parameter_validation = ensure_boolean(raw_value)
 
-
         s3_config = self.compute_s3_config(client_config)
 
         configured_endpoint_url = self._compute_configured_endpoint_url(

awscli/botocore/handlers.py

@@ -114,41 +114,13 @@ def escape_xml_payload(params, **kwargs):
     params['body'] = body
 
 
-def check_for_200_error(response, **kwargs):
-    # From: http://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectCOPY.html
-    # There are two opportunities for a copy request to return an error. One
-    # can occur when Amazon S3 receives the copy request and the other can
-    # occur while Amazon S3 is copying the files. If the error occurs before
-    # the copy operation starts, you receive a standard Amazon S3 error. If the
-    # error occurs during the copy operation, the error response is embedded in
-    # the 200 OK response. This means that a 200 OK response can contain either
-    # a success or an error. Make sure to design your application to parse the
-    # contents of the response and handle it appropriately.
-    #
-    # So this handler checks for this case.  Even though the server sends a
-    # 200 response, conceptually this should be handled exactly like a
-    # 500 response (with respect to raising exceptions, retries, etc.)
-    # We're connected *before* all the other retry logic handlers, so as long
-    # as we switch the error code to 500, we'll retry the error as expected.
-    if response is None:
-        # A None response can happen if an exception is raised while
-        # trying to retrieve the response.  See Endpoint._get_response().
-        return
-    http_response, parsed = response
-    if _looks_like_special_case_error(http_response):
-        logger.debug("Error found for response with 200 status code, "
-                     "errors: %s, changing status code to "
-                     "500.", parsed)
-        http_response.status_code = 500
-
-
-def _looks_like_special_case_error(http_response):
-    if http_response.status_code == 200:
+def _looks_like_special_case_error(status_code, body):
+    if status_code == 200 and body:
         try:
             parser = ETree.XMLParser(
                 target=ETree.TreeBuilder(),
                 encoding='utf-8')
-            parser.feed(http_response.content)
+            parser.feed(body)
             root = parser.close()
         except XMLParseError:
             # In cases of network disruptions, we may end up with a partial
@@ -1134,6 +1106,51 @@ def document_expires_shape(section, event_name, **kwargs):
         )
 
 
+def _handle_200_error(operation_model, response_dict, **kwargs):
+    # S3 can return a 200 response with an error embedded in the body.
+    # Convert the 200 to a 500 for retry resolution in ``_update_status_code``.
+    if not _should_handle_200_error(operation_model, response_dict):
+        # Operations with streaming response blobs are excluded as they
+        # can't be reliably distinguished from an S3 error.
+        return
+    if _looks_like_special_case_error(
+        response_dict['status_code'], response_dict['body']
+    ):
+        response_dict['status_code'] = 500
+        logger.debug(
+            f"Error found for response with 200 status code: {response_dict['body']}."
+        )
+
+
+def _should_handle_200_error(operation_model, response_dict):
+    output_shape = operation_model.output_shape
+    if (
+        not response_dict
+        or operation_model.has_event_stream_output
+        or not output_shape
+    ):
+        return False
+    payload = output_shape.serialization.get('payload')
+    if payload is not None:
+        payload_shape = output_shape.members[payload]
+        if payload_shape.type_name in ('blob', 'string'):
+            return False
+    return True
+
+
+def _update_status_code(response, **kwargs):
+    # Update the http_response status code when the parsed response has been
+    # modified in a handler. This enables retries for cases like ``_handle_200_error``.
+    if response is None:
+        return
+    http_response, parsed = response
+    parsed_status_code = parsed.get('ResponseMetadata', {}).get(
+        'HTTPStatusCode', http_response.status_code
+    )
+    if http_response.status_code != parsed_status_code:
+        http_response.status_code = parsed_status_code
+
+
 # This is a list of (event_name, handler).
 # When a Session is created, everything in this list will be
 # automatically registered with that Session.
@@ -1158,6 +1175,7 @@ def document_expires_shape(section, event_name, **kwargs):
     ('after-call.cloudformation.GetTemplate', json_decode_template_body),
     ('after-call.s3.GetBucketLocation', parse_get_bucket_location),
     ('before-parse.s3.*', handle_expires_header),
+    ('before-parse.s3.*', _handle_200_error, REGISTER_FIRST),
     ('before-parameter-build', generate_idempotent_uuid),
 
     ('before-parameter-build.s3', validate_bucket_name),
@@ -1196,10 +1214,7 @@ def document_expires_shape(section, event_name, **kwargs):
     ('before-call.glacier.UploadMultipartPart', add_glacier_checksums),
     ('before-call.ec2.CopySnapshot', inject_presigned_url_ec2),
     ('request-created.machine-learning.Predict', switch_host_machinelearning),
-    ('needs-retry.s3.UploadPartCopy', check_for_200_error, REGISTER_FIRST),
-    ('needs-retry.s3.CopyObject', check_for_200_error, REGISTER_FIRST),
-    ('needs-retry.s3.CompleteMultipartUpload', check_for_200_error,
-     REGISTER_FIRST),
+    ('needs-retry.s3.*', _update_status_code, REGISTER_FIRST),
     ('choose-signer.cognito-identity.GetId', disable_signing),
     ('choose-signer.cognito-identity.GetOpenIdToken', disable_signing),
     ('choose-signer.cognito-identity.UnlinkIdentity', disable_signing),

tests/functional/botocore/test_s3.py

@@ -29,7 +29,6 @@
     UnsupportedS3ConfigurationError,
     UnsupportedS3AccesspointConfigurationError,
 )
-from botocore.parsers import ResponseParserError
 from botocore.loaders import Loader
 from botocore import UNSIGNED
 
@@ -358,12 +357,12 @@ def create_stubbed_s3_client(self, **kwargs):
         http_stubber.start()
         return client, http_stubber
 
-    def test_s3_copy_object_with_empty_response(self):
+    def test_s3_copy_object_with_incomplete_response(self):
         self.client, self.http_stubber = self.create_stubbed_s3_client(
             region_name='us-east-1'
         )
 
-        empty_body = b''
+        incomplete_body = b'<?xml version="1.0" encoding="UTF-8"?>\n\n\n'
         complete_body = (
             b'<?xml version="1.0" encoding="UTF-8"?>\n\n'
             b'<CopyObjectResult '
@@ -372,7 +371,7 @@ def test_s3_copy_object_with_empty_response(self):
             b'<ETag>&quot;s0mEcH3cK5uM&quot;</ETag></CopyObjectResult>'
         )
 
-        self.http_stubber.add_response(status=200, body=empty_body)
+        self.http_stubber.add_response(status=200, body=incomplete_body)
         self.http_stubber.add_response(status=200, body=complete_body)
         response = self.client.copy_object(
             Bucket='bucket',
@@ -385,19 +384,86 @@ def test_s3_copy_object_with_empty_response(self):
         self.assertEqual(response['ResponseMetadata']['HTTPStatusCode'], 200)
         self.assertTrue('CopyObjectResult' in response)
 
-    def test_s3_copy_object_with_incomplete_response(self):
+
+class TestS3200ErrorResponse(BaseS3OperationTest):
+    def create_s3_client(self, **kwargs):
+        client_kwargs = {"region_name": self.region}
+        client_kwargs.update(kwargs)
+        return self.session.create_client("s3", **client_kwargs)
+
+    def create_stubbed_s3_client(self, **kwargs):
+        client = self.create_s3_client(**kwargs)
+        http_stubber = ClientHTTPStubber(client)
+        http_stubber.start()
+        return client, http_stubber
+
+    def test_s3_200_with_error_response(self):
         self.client, self.http_stubber = self.create_stubbed_s3_client(
             region_name='us-east-1'
         )
-
-        incomplete_body = b'<?xml version="1.0" encoding="UTF-8"?>\n\n\n'
-        self.http_stubber.add_response(status=200, body=incomplete_body)
-        with self.assertRaises(ResponseParserError):
+        error_body = (
+            b"<Error>"
+            b"<Code>SlowDown</Code>"
+            b"<Message>Please reduce your request rate.</Message>"
+            b"</Error>"
+        )
+        # Populate 3 attempts for SlowDown to validate
+        # we reached two max retries and raised an exception.
+        for i in range(3):
+            self.http_stubber.add_response(status=200, body=error_body)
+        with self.assertRaises(botocore.exceptions.ClientError) as context:
             self.client.copy_object(
                 Bucket='bucket',
                 CopySource='other-bucket/test.txt',
                 Key='test.txt',
             )
+        self.assertEqual(len(self.http_stubber.requests), 3)
+        self.assertEqual(
+            context.exception.response["ResponseMetadata"]["HTTPStatusCode"],
+            500,
+        )
+        self.assertEqual(
+            context.exception.response["Error"]["Code"], "SlowDown"
+        )
+
+    def test_s3_200_with_no_error_response(self):
+        self.client, self.http_stubber = self.create_stubbed_s3_client(
+            region_name="us-east-1"
+        )
+        self.http_stubber.add_response(status=200, body=b"<NotAnError/>")
+
+        response = self.client.copy_object(
+            Bucket="bucket",
+            CopySource="other-bucket/test.txt",
+            Key="test.txt",
+        )
+
+        # Validate that the status code remains 200.
+        self.assertEqual(len(self.http_stubber.requests), 1)
+        self.assertEqual(response["ResponseMetadata"]["HTTPStatusCode"], 200)
+
+    def test_s3_200_with_error_response_on_streaming_operation(self):
+        self.client, self.http_stubber = self.create_stubbed_s3_client(
+            region_name="us-east-1"
+        )
+        self.http_stubber.add_response(status=200, body=b"<Error/>")
+        response = self.client.get_object(Bucket="bucket", Key="test.txt")
+
+        # Validate that the status code remains 200 because we don't
+        # process 200-with-error responses on streaming operations.
+        self.assertEqual(len(self.http_stubber.requests), 1)
+        self.assertEqual(response["ResponseMetadata"]["HTTPStatusCode"], 200)
+
+    def test_s3_200_response_with_no_body(self):
+        self.client, self.http_stubber = self.create_stubbed_s3_client(
+            region_name="us-east-1"
+        )
+        self.http_stubber.add_response(status=200)
+        response = self.client.head_object(Bucket="bucket", Key="test.txt")
+
+        # Validate that the status code remains 200 on operations without a body.
+        self.assertEqual(len(self.http_stubber.requests), 1)
+        self.assertEqual(response["ResponseMetadata"]["HTTPStatusCode"], 200)
 
 
 class TestAccesspointArn(BaseS3ClientConfigurationTest):

tests/functional/s3/test_mv_command.py

@@ -16,7 +16,6 @@
 from awscrt.s3 import S3RequestType
 
 from awscli.compat import BytesIO
-from awscli.customizations.s3.utils import S3PathResolver
 from awscli.testutils import mock
 from tests.functional.s3 import (
     BaseS3TransferCommandTest, BaseCRTTransferClientTest

tests/unit/botocore/test_handlers.py

@@ -429,33 +429,6 @@ def test_presigned_url_casing_changed_for_rds(self):
                       params['PreSignedUrl'])
         self.assertIn('X-Amz-Signature', params['PreSignedUrl'])
 
-    def test_500_status_code_set_for_200_response(self):
-        http_response = mock.Mock()
-        http_response.status_code = 200
-        http_response.content = """
-            <Error>
-              <Code>AccessDenied</Code>
-              <Message>Access Denied</Message>
-              <RequestId>id</RequestId>
-              <HostId>hostid</HostId>
-            </Error>
-        """
-        handlers.check_for_200_error((http_response, {}))
-        self.assertEqual(http_response.status_code, 500)
-
-    def test_200_response_with_no_error_left_untouched(self):
-        http_response = mock.Mock()
-        http_response.status_code = 200
-        http_response.content = "<NotAnError></NotAnError>"
-        handlers.check_for_200_error((http_response, {}))
-        # We don't touch the status code since there are no errors present.
-        self.assertEqual(http_response.status_code, 200)
-
-    def test_500_response_can_be_none(self):
-        # A 500 response can raise an exception, which means the response
-        # object is None.  We need to handle this case.
-        handlers.check_for_200_error(None)
-
     def test_route53_resource_id(self):
         event = 'before-parameter-build.route-53.GetHostedZone'
         params = {'Id': '/hostedzone/ABC123',
@@ -1138,14 +1111,14 @@ def test_s3_special_case_is_before_other_retry(self):
             response=(mock.Mock(), mock.Mock()), endpoint=mock.Mock(),
             operation=operation, attempts=1, caught_exception=None)
         # This is implementation specific, but we're trying to verify that
-        # the check_for_200_error is before any of the retry logic in
+        # the _update_status_code is before any of the retry logic in
         # botocore.retries.*.
         # Technically, as long as the relative order is preserved, we don't
         # care about the absolute order.
         names = self.get_handler_names(responses)
-        self.assertIn('check_for_200_error', names)
+        self.assertIn('_update_status_code', names)
         self.assertIn('needs_retry', names)
-        s3_200_handler = names.index('check_for_200_error')
+        s3_200_handler = names.index('_update_status_code')
         general_retry_handler = names.index('needs_retry')
         self.assertTrue(s3_200_handler < general_retry_handler,
                         "S3 200 error handler was supposed to be before "