Allow dotted dict as the restriction key

README.rst

@@ -147,6 +147,23 @@ If you want to specify locking based on a subset, or no arguments you can adjust
         ..
     AlreadyQueued()
 
+And in case you want a key inside a dict parameter as your lock key, you could use a string with its `dotted notation path <https://github.com/carlosescri/DottedDict/blob/master/README.rst#example-2-dotteddict>`_:
+
+.. code:: python
+
+    @celery.task(base=QueueOnce, once={'keys': ['payload.a']})
+    def slow_payload_add(payload, b):
+        sleep(30)
+        return payload['a'] + b
+
+    example.delay({'a': 1, 'another_key': 'any'}, 1)
+    # Checks if any tasks are running with the `a=1`
+    example.delay({'a': 1, 'another_key_again': 'any other'}, 2)
+    Traceback (most recent call last):
+        ..
+    AlreadyQueued()
+    example.delay({'a': 2}, 2)
+
 
 ``timeout``
 -----------
@@ -215,7 +232,7 @@ The URL parser supports three patterns of urls:
   The ``options`` query args are mapped to the `StrictRedis <https://redis-py.readthedocs.org/en/latest/index.html#redis.StrictRedis>`_ keyword args.
   Examples:
   * ``redis://localhost:6379/1``
-  
+
   * ``redis://localhost:6379/1?ssl=true``
 
   * ``rediss://localhost:6379/1``

celery_once/helpers.py

@@ -7,6 +7,8 @@
 import importlib
 from collections import OrderedDict
 
+from dotted.collection import DottedDict
+
 
 def import_backend(config):
     """
@@ -67,7 +69,8 @@ def queue_once_key(name, kwargs, restrict_to=None):
     keys = ['qo', force_string(name)]
     # Restrict to only the keys allowed in keys.
     if restrict_to is not None:
-        restrict_kwargs = {key: kwargs[key] for key in restrict_to}
+        dotted_kwargs = DottedDict(kwargs)
+        restrict_kwargs = {key: dotted_kwargs[key] for key in restrict_to}
         keys += kwargs_to_list(restrict_kwargs)
     else:
         keys += kwargs_to_list(kwargs)

setup.py

@@ -8,7 +8,8 @@
 
 requirements = [
     "celery",
-    "redis>=2.10.2"
+    "redis>=2.10.2",
+    "dotted>=0.1.8",
 ]
 
 __version__ = ''

tests/unit/test_helpers.py

@@ -93,6 +93,11 @@ def test_queue_once_key_kwargs_restrict_keys():
     assert key == "qo_example_pk-10"
 
 
+def test_queue_once_key_kwargs_restrict_dotted_keys():
+    key = queue_once_key("example", {'dict': {'pk': 10}, 'id': 10}, restrict_to=['dict.pk'])
+    assert key == "qo_example_dict.pk-10"
+
+
 @pytest.mark.skipif(six.PY3, reason='requires python 2')
 def test_queue_once_key_unicode_py2():
     key = queue_once_key(u"éxample", {'a': u'é', u'b': 'é'})

tests/unit/test_tasks.py

@@ -23,6 +23,11 @@ def select_args_example(a, b):
     return a + b
 
 
+@task(name='select_args_dict_example', base=QueueOnce, once={'keys': ['payload.a']})
+def select_args_dict_example(payload, b):
+    return payload['a'] + b
+
+
 @task(name='autoretry_for_example', base=QueueOnce, autoretry_for=(Exception,))
 def autoretry_for_example(a, b):
     return a + b
@@ -46,6 +51,11 @@ def test_get_key_select_args_1():
         kwargs={'a': 1, 'b': 2})
 
 
+def test_get_dotted_key_select_args_1():
+    assert "qo_select_args_dict_example_payload.a-1" ==\
+        select_args_dict_example.get_key(kwargs={'payload': {'a': 1}, 'b': 2})
+
+
 def test_get_key_bound_task():
     assert "qo_bound_task_a-1_b-2" == bound_task.get_key(
         kwargs={'a': 1, 'b': 2})