fix: helpful error message when deploy happens across regions

samcli/commands/deploy/exceptions.py

@@ -47,6 +47,15 @@ def __init__(self, stack_name, msg):
         )
 
 
+class DeployBucketInDifferentRegionError(UserException):
+    def __init__(self, msg):
+        self.msg = msg
+
+        message_fmt = "{msg} : deployment s3 bucket is in a different region, try sam deploy --guided"
+
+        super(DeployBucketInDifferentRegionError, self).__init__(message=message_fmt.format(msg=self.msg))
+
+
 class DeployBucketRequiredError(UserException):
     def __init__(self):
 

samcli/lib/deploy/deployer.py

@@ -25,7 +25,12 @@
 import botocore
 
 from samcli.lib.deploy.utils import DeployColor
-from samcli.commands.deploy.exceptions import DeployFailedError, ChangeSetError, DeployStackOutPutFailedError
+from samcli.commands.deploy.exceptions import (
+    DeployFailedError,
+    ChangeSetError,
+    DeployStackOutPutFailedError,
+    DeployBucketInDifferentRegionError,
+)
 from samcli.commands._utils.table_print import pprint_column_names, pprint_columns
 from samcli.commands.deploy import exceptions as deploy_exceptions
 from samcli.lib.package.artifact_exporter import mktempfile, parse_s3_url
@@ -176,6 +181,10 @@ def create_changeset(
         try:
             resp = self._client.create_change_set(**kwargs)
             return resp, changeset_type
+        except botocore.exceptions.ClientError as ex:
+            if "The bucket you are attempting to access must be addressed using the specified endpoint" in str(ex):
+                raise DeployBucketInDifferentRegionError(f"Failed to create/update stack {stack_name}")
+
         except Exception as ex:
             LOG.debug("Unable to create changeset", exc_info=ex)
             raise ChangeSetError(stack_name=stack_name, msg=str(ex))

tests/unit/lib/deploy/test_deployer.py

@@ -6,7 +6,12 @@
 
 from botocore.exceptions import ClientError, WaiterError, BotoCoreError
 
-from samcli.commands.deploy.exceptions import DeployFailedError, ChangeSetError, DeployStackOutPutFailedError
+from samcli.commands.deploy.exceptions import (
+    DeployFailedError,
+    ChangeSetError,
+    DeployStackOutPutFailedError,
+    DeployBucketInDifferentRegionError,
+)
 from samcli.lib.deploy.deployer import Deployer
 from samcli.lib.package.s3_uploader import S3Uploader
 from samcli.lib.utils.time import utc_to_timestamp, to_datetime
@@ -158,6 +163,36 @@ def test_create_changeset_exception(self):
                 tags={"unit": "true"},
             )
 
+    def test_create_changeset_ClientErrorException(self):
+        error_message = (
+            "An error occurred (ValidationError) when calling the CreateChangeSet "
+            "operation: S3 error: The bucket you are attempting to access must be "
+            "addressed using the specified endpoint. "
+            "Please send all future requests to this "
+            "endpoint.\nFor more information "
+            "check http://docs.aws.amazon.com/AmazonS3/latest/API/ErrorResponses.html"
+        )
+        self.deployer.has_stack = MagicMock(return_value=False)
+        self.deployer._client.create_change_set = MagicMock(
+            side_effect=ClientError(
+                error_response={"Error": {"Message": error_message}}, operation_name="create_changeset"
+            )
+        )
+        with self.assertRaises(DeployBucketInDifferentRegionError):
+            self.deployer.create_changeset(
+                stack_name="test",
+                cfn_template=" ",
+                parameter_values=[
+                    {"ParameterKey": "a", "ParameterValue": "b"},
+                    {"ParameterKey": "c", "UsePreviousValue": True},
+                ],
+                capabilities=["CAPABILITY_IAM"],
+                role_arn="role-arn",
+                notification_arns=[],
+                s3_uploader=S3Uploader(s3_client=self.s3_client, bucket_name="test_bucket"),
+                tags={"unit": "true"},
+            )
+
     def test_describe_changeset_with_changes(self):
         response = [
             {