refactor gevent.Event sync into a context manager

src/ga.py

@@ -156,15 +156,13 @@ def pop_gen (self, *args, **kwargs):
         payload, start_response, body = worker.get_response_context(args[1:])
 
         if worker.auth_request(payload, start_response, body):
-            worker.init_task_event()
+            with worker.wrap_task_event():
+                # HTTP response first, then initiate long-running task
+                start_response('200 OK', [('Content-Type', 'text/plain')])
+                body.put("Bokay\r\n")
+                body.put(StopIteration)
 
-            # HTTP response first, then initiate long-running task
-            start_response('200 OK', [('Content-Type', 'text/plain')])
-            body.put("Bokay\r\n")
-            body.put(StopIteration)
-
-            self.populate(0)
-            worker.done_task_event()
+                self.populate(0)
 
 
     def pop_hist (self, *args, **kwargs):
@@ -185,18 +183,15 @@ def pop_next (self, *args, **kwargs):
         payload, start_response, body = worker.get_response_context(args[1:])
 
         if worker.auth_request(payload, start_response, body):
-            worker.init_task_event()
-
-            # HTTP response first, then initiate long-running task
-            start_response('200 OK', [('Content-Type', 'text/plain')])
-            body.put("Bokay\r\n")
-            body.put(StopIteration)
-
-            current_gen = payload["current_gen"]
-            fitness_cutoff = payload["fitness_cutoff"]
-            self.next_generation(current_gen, fitness_cutoff)
-
-            worker.done_task_event()
+            with worker.wrap_task_event():
+                # HTTP response first, then initiate long-running task
+                start_response('200 OK', [('Content-Type', 'text/plain')])
+                body.put("Bokay\r\n")
+                body.put(StopIteration)
+
+                current_gen = payload["current_gen"]
+                fitness_cutoff = payload["fitness_cutoff"]
+                self.next_generation(current_gen, fitness_cutoff)
 
 
     def pop_enum (self, *args, **kwargs):

src/service.py

@@ -17,6 +17,7 @@
 # https://github.com/ceteri/exelixi
 
 
+from contextlib import contextmanager
 from gevent import monkey, shutdown, signal, spawn, wsgi, Greenlet
 from gevent.event import Event
 from gevent.queue import JoinableQueue
@@ -127,13 +128,13 @@ def shard_config (self, *args, **kwargs):
     ######################################################################
     ## barrier pattern methods
 
-    def init_task_event (self):
+    @contextmanager
+    def wrap_task_event (self):
         """initialize a gevent.Event, to which the UnitOfWork will wait as a listener"""
         self._task_event = Event()
+        yield
 
-
-    def done_task_event (self):
-        """complete a gevent.Event, notifying the UnitOfWork which waited as a listener"""
+        # complete the Event, notifying the UnitOfWork which waited
         self._task_event.set()
         self._task_event = None