fix: update get_execution_role to directly return the ExecutionRoleArn if it presents in the resource metadata file

Author: Jun Lyu

src/sagemaker/session.py

@@ -6285,16 +6285,16 @@ def get_caller_identity_arn(self):
                 user_profile_name = metadata.get("UserProfileName")
                 execution_role_arn = metadata.get("ExecutionRoleArn")
             try:
+                # find execution role from the metadata file if present
+                if execution_role_arn is not None:
+                    return execution_role_arn
+
                 if domain_id is None:
                     instance_desc = self.sagemaker_client.describe_notebook_instance(
                         NotebookInstanceName=instance_name
                     )
                     return instance_desc["RoleArn"]
 
-                # find execution role from the metadata file if present
-                if execution_role_arn is not None:
-                    return execution_role_arn
-
                 user_profile_desc = self.sagemaker_client.describe_user_profile(
                     DomainId=domain_id, UserProfileName=user_profile_name
                 )

tests/unit/test_session.py

@@ -728,6 +728,25 @@ def test_get_caller_identity_arn_from_metadata_file_for_space(boto_session):
     assert actual == expected_role
 
 
+@patch(
+    "six.moves.builtins.open",
+    mock_open(
+        read_data='{"ResourceName": "SageMakerInstance", '
+        '"ExecutionRoleArn": "arn:aws:iam::369233609183:role/service-role/SageMakerRole-20171129T072388"}'
+    ),
+)
+@patch("os.path.exists", side_effect=mock_exists(NOTEBOOK_METADATA_FILE, True))
+def test_get_caller_identity_arn_from_metadata_file_with_no_domain_id(boto_session):
+    sess = Session(boto_session)
+    expected_role = "arn:aws:iam::369233609183:role/service-role/SageMakerRole-20171129T072388"
+
+    actual = sess.get_caller_identity_arn()
+
+    assert actual == expected_role
+    # Should not call describe_notebook_instance since ExecutionRoleArn is available
+    sess.sagemaker_client.describe_notebook_instance.assert_not_called()
+
+
 @patch(
     "six.moves.builtins.open",
     mock_open(read_data='{"ResourceName": "SageMakerInstance"}'),