support nesting tasks using a single-invocation patched method

Author: Alexey Tsitkin

eb_sqs/auto_tasks/base_service.py

@@ -1,7 +1,6 @@
 import importlib
 import logging
 
-from eb_sqs.auto_tasks.base_service import BaseAutoTaskService, NoopTaskService
 from eb_sqs.auto_tasks.exceptions import RetryableTaskException
 from eb_sqs.decorators import task
 from eb_sqs.worker.worker_exceptions import MaxRetriesReachedException
@@ -24,11 +23,12 @@ def _auto_task_wrapper(module_name, class_name, func_name, *args, **kwargs):
         module = importlib.import_module(module_name)  # import module
         class_ = getattr(module, class_name)  # find class
 
-        noop_task_service = NoopTaskService()
-        instance = class_(auto_task_service=noop_task_service)  # instantiate class using NoopTaskService
+        auto_task_executor_service = _AutoTaskExecutorService(func_name)
+        instance = class_(auto_task_service=auto_task_executor_service)  # instantiate class using _AutoTaskExecutorService
 
-        if noop_task_service.is_func_name_registered(func_name):
-            getattr(instance, func_name)(*args, **kwargs)  # invoke method on instance
+        executor_func_name = auto_task_executor_service.get_executor_func_name()
+        if executor_func_name:
+            getattr(instance, executor_func_name)(*args, **kwargs)  # invoke method on instance
         else:
             logger.error(
                 'Trying to invoke _auto_task_wrapper for unregistered task with module: %s class: %s func: %s args: %s and kwargs: %s',
@@ -57,7 +57,7 @@ def _auto_task_wrapper(module_name, class_name, func_name, *args, **kwargs):
                 logger.error('Reached max retries in auto task {}.{}.{} with error: {}'.format(module_name, class_name, func_name, repr(exc)))
 
 
-class AutoTaskService(BaseAutoTaskService):
+class AutoTaskService(object):
     def register_task(self, method, queue_name=None, max_retries=None):
         # type: (Any, str, int) -> None
         instance = method.__self__
@@ -79,3 +79,26 @@ def _auto_task_wrapper_invoker(*args, **kwargs):
             )
 
         setattr(instance, func_name, _auto_task_wrapper_invoker)
+
+
+class _AutoTaskExecutorService(AutoTaskService):
+    def __init__(self, func_name):
+        # type: (str) -> None
+        self._func_name = func_name
+
+        self._executor_func_name = None
+
+    def register_task(self, method, queue_name=None, max_retries=None):
+        # type: (Any, str, int) -> None
+        if self._func_name == method.__name__:
+            # circuit breaker to allow actually executing the method once
+            instance = method.__self__
+
+            self._executor_func_name = self._func_name + '__auto_task_executor__'
+            setattr(instance, self._executor_func_name, getattr(instance, self._func_name))
+
+        super(_AutoTaskExecutorService, self).register_task(method, queue_name, max_retries)
+
+    def get_executor_func_name(self):
+        # type: () -> str
+        return self._executor_func_name

eb_sqs/auto_tasks/service.py

@@ -13,9 +13,13 @@ class TestService:
 
     def __init__(self, auto_task_service=None):
         self._auto_task_service = auto_task_service or AutoTaskService()
+
         self._auto_task_service.register_task(self.task_method)
         self._auto_task_service.register_task(self.task_retry_method, max_retries=self._MAX_RETRY_NUM)
 
+        self._auto_task_service.register_task(self.task_recursive_method)
+        self._auto_task_service.register_task(self.task_other_method)
+
     def task_method(self, *args, **kwargs):
         self._TEST_MOCK.task_method(*args, **kwargs)
 
@@ -30,6 +34,15 @@ def max_retry_fun():
     def non_task_method(self):
         self._TEST_MOCK.non_task_method()
 
+    def task_recursive_method(self, tries=2):
+        if tries > 0:
+            self.task_recursive_method(tries=tries - 1)
+        else:
+            self.task_other_method()
+
+    def task_other_method(self):
+        self._TEST_MOCK.task_other_method()
+
 
 class AutoTasksTest(TestCase):
     def setUp(self):
@@ -61,3 +74,8 @@ def test_non_task_method(self):
         )
 
         TestService._TEST_MOCK.non_task_method.assert_not_called()
+
+    def test_task_recursive_method(self):
+        self._test_service.task_recursive_method()
+
+        TestService._TEST_MOCK.task_other_method.assert_called_once_with()

eb_sqs/tests/auto_tasks/tests_auto_tasks.py

@@ -6,7 +6,7 @@
 
 setup(
     name='django-eb-sqs',
-    version='1.31',
+    version='1.32',
     package_dir={'eb_sqs': 'eb_sqs'},
     include_package_data=True,
     packages=find_packages(),