Merge pull request #204 from onefinestay/saner_timer

simpler timer implementation

nameko/timer.py

@@ -11,14 +11,12 @@
 
 
 class Timer(Entrypoint):
-    def __init__(self, interval=None, config_key=None):
+    def __init__(self, interval):
         """
         Timer entrypoint implementation. Fires every :attr:`self.interval`
         seconds.
 
-        Either `interval` or `config_key` must be provided. If given,
-        `config_key` specifies a key in the config will be used as the
-        interval.
+        The implementation sleeps first, i.e. does not fire at time 0.
 
         Example::
 
@@ -28,25 +26,15 @@ class Service(object):
 
                 @timer(interval=5)
                 def tick(self):
-                    self.shrub(body)
+                    pass
 
-                @timer(config_key='tock_interval')
-                def tock(self):
-                    self.shrub(body)
         """
-        self._default_interval = interval
-        self.config_key = config_key
+        self.interval = interval
         self.should_stop = Event()
         self.gt = None
 
     def start(self):
         _log.debug('starting %s', self)
-        interval = self._default_interval
-
-        if self.config_key:
-            interval = self.container.config.get(self.config_key, interval)
-
-        self.interval = interval
         self.gt = self.container.spawn_managed_thread(self._run)
 
     def stop(self):
@@ -59,30 +47,26 @@ def kill(self):
         self.gt.kill()
 
     def _run(self):
-        ''' Runs the interval loop.
+        """ Runs the interval loop. """
+
+        sleep_time = self.interval
+
+        while True:
+            # sleep for `sleep_time`, unless `should_stop` fires, in which
+            # case we leave the while loop and stop entirely
+            with Timeout(sleep_time, exception=False):
+                self.should_stop.wait()
+                break
 
-        This should not be called directly, rather the `start()` method
-        should be used.
-        '''
-        while not self.should_stop.ready():
             start = time.time()
 
             self.handle_timer_tick()
 
             elapsed_time = (time.time() - start)
+
+            # next time, sleep however long is left of our interval, taking
+            # off the time we took to run
             sleep_time = max(self.interval - elapsed_time, 0)
-            self._sleep_or_stop(sleep_time)
-
-    def _sleep_or_stop(self, sleep_time):
-        ''' Sleeps for `sleep_time` seconds or until a `should_stop` event
-        has been fired, whichever comes first.
-        '''
-        try:
-            with Timeout(sleep_time):
-                self.should_stop.wait()
-        except Timeout:
-            # we use the timeout as a cancellable sleep
-            pass
 
     def handle_timer_tick(self):
         args = ()

test/test_timers.py

@@ -11,14 +11,13 @@
 def test_provider():
     container = Mock(spec=ServiceContainer)
     container.service_name = "service"
-    container.config = Mock()
     container.spawn_managed_thread = eventlet.spawn
 
-    timer = Timer(interval=0).bind(container, "method")
+    timer = Timer(interval=0.1).bind(container, "method")
     timer.setup()
     timer.start()
 
-    assert timer.interval == 0
+    assert timer.interval == 0.1
 
     with wait_for_call(1, container.spawn_worker) as spawn_worker:
         with Timeout(1):
@@ -30,33 +29,6 @@ def test_provider():
     assert timer.gt.dead
 
 
-def test_provider_uses_config_for_interval():
-    container = Mock(spec=ServiceContainer)
-    container.service_name = "service"
-    container.config = {'spam-conf': 10}
-    container.spawn_managed_thread = eventlet.spawn
-
-    timer = Timer(config_key='spam-conf').bind(container, "method")
-    timer.setup()
-    timer.start()
-
-    assert timer.interval == 10
-    timer.stop()
-
-
-def test_provider_interval_as_config_fallback():
-    container = Mock(spec=ServiceContainer)
-    container.service_name = "service"
-    container.config = {}
-
-    timer = Timer(interval=1, config_key='spam-conf').bind(container, "method")
-    timer.setup()
-    timer.start()
-
-    assert timer.interval == 1
-    timer.stop()
-
-
 def test_stop_timer_immediatly():
     container = Mock(spec=ServiceContainer)
     container.service_name = "service"