Add support for SingularTaskFailure

Author: grktsh

src/cloud_tasks_deferred/deferred.py

@@ -94,6 +94,10 @@ class PermanentTaskFailure(Error):
     """Indicates that a task failed, and will never succeed."""
 
 
+class SingularTaskFailure(Error):
+    """Indicates that a task failed once."""
+
+
 class InvalidTaskError(Error):
     """The parameters, headers, or method of the task is invalid."""
 

src/cloud_tasks_deferred/wsgi.py

@@ -43,6 +43,9 @@ def abort(status):
 
     try:
         deferred.run(data)
+    except deferred.SingularTaskFailure:
+        logger.debug('Failure executing task, task retry forced')
+        return abort('408 Request Timeout')
     except deferred.PermanentTaskFailure:
         logger.exception('Permanent failure attempting to execute task')
     except Exception:

tests/test_wsgi.py

@@ -10,6 +10,7 @@
 import pytest
 from falcon import testing
 
+from cloud_tasks_deferred import deferred
 from cloud_tasks_deferred import wsgi
 
 
@@ -52,6 +53,16 @@ def test_application(simulate_post):
     assert response.status == falcon.HTTP_NO_CONTENT
 
 
+def test_application_singular_task_failure(simulate_post, mocker):
+    mocker.patch(
+        'cloud_tasks_deferred.deferred.run',
+        side_effect=deferred.SingularTaskFailure,
+    )
+    body = pickle.dumps((bool, (), {}))
+    response = simulate_post(body=body)
+    assert response.status == '408 Request Timeout'
+
+
 def test_application_permanent_task_failure(simulate_post):
     body = pickle.dumps('can not deserialize')
     response = simulate_post(body=body)