default aloop used for background tasks

atasker/supervisor.py

@@ -299,9 +299,12 @@ def create_aloop(self, name, daemon=False, start=True, default=False):
     def set_default_aloop(self, aloop):
         self.default_aloop = aloop
 
-    def get_aloop(self, name):
+    def get_aloop(self, name=None, default=True):
         with self._lock:
-            return self.aloops.get(name)
+            if name is not None:
+                return self.aloops.get(name)
+            elif default:
+                return self.default_aloop
 
     def start_aloop(self, name):
         with self._lock:

atasker/threads.py

@@ -136,10 +136,11 @@ def background_task(f, *args, **kwargs):
         tt: TT_THREAD (default) or TT_MP (TT_COROUTINE is detected
             automatically)
         callback: callback function for TT_MP
-        loop: asyncio loop or aloop object
+        loop: asyncio loop or aloop object (optional)
 
     Raises:
-        RuntimeError if coroutine function is used but loop is not specified
+        RuntimeError: if coroutine function is used but loop is not specified
+            and supervisor doesn't have default aloop
     """
 
     def gen_mp_callback(task_id, callback, supervisor):
@@ -157,6 +158,8 @@ def start_task(*args, **kw):
         supervisor = kwargs.get('supervisor', task_supervisor)
         if tt == TT_COROUTINE or asyncio.iscoroutinefunction(f):
             loop = kwargs.get('loop')
+            if isinstance(loop, str) or loop is None:
+                loop = supervisor.get_aloop(loop)
             if not loop:
                 raise RuntimeError('loop not specified')
             if isinstance(loop, ALoop):

tests/test.py

@@ -244,7 +244,7 @@ async def t2(x):
             return x * 2
 
         a = task_supervisor.create_aloop('test2')
-        background_task(t1, loop=a)()
+        background_task(t1, loop='test2')()
         wait()
         self.assertEqual(result.test_aloop_background_task, 1)
         self.assertEqual(a.run(t2(2)), 4)