Use monotonic clock for timing scheduler loop interval.

Refs and resolves #521

huey/consumer.py

@@ -46,13 +46,13 @@ def sleep_for_interval(self, start_ts, nseconds):
         if the current timestamp is 1340, we'll only sleep for 7 seconds (the
         goal being to sleep until 1347, or 1337 + 10).
         """
-        sleep_time = nseconds - (time.time() - start_ts)
+        sleep_time = nseconds - (time_clock() - start_ts)
         if sleep_time <= 0:
             return
         self._logger.debug('Sleeping for %s', sleep_time)
         # Recompute time to sleep to improve accuracy in case the process was
         # pre-empted by the kernel while logging.
-        sleep_time = nseconds - (time.time() - start_ts)
+        sleep_time = nseconds - (time_clock() - start_ts)
         if sleep_time > 0:
             time.sleep(sleep_time)
 
@@ -145,13 +145,13 @@ def __init__(self, huey, interval, periodic):
         self.interval = min(interval, 60)
 
         self.periodic = periodic
-        self._next_loop = time.time()
-        self._next_periodic = time.time()
+        self._next_loop = time_clock()
+        self._next_periodic = time_clock()
 
     def loop(self, now=None):
         current = self._next_loop
         self._next_loop += self.interval
-        if self._next_loop < time.time():
+        if self._next_loop < time_clock():
             self._logger.debug('scheduler skipping iteration to avoid race.')
             return
 
@@ -166,7 +166,7 @@ def loop(self, now=None):
 
         if self.periodic:
             current_p = self._next_periodic
-            if current_p <= time.time():
+            if current_p <= time_clock():
                 self._next_periodic += 60
                 self.enqueue_periodic_tasks(now)
 

huey/tests/test_consumer.py

@@ -6,6 +6,7 @@
 from huey.consumer import Scheduler
 from huey.consumer_options import ConsumerConfig
 from huey.tests.base import BaseTestCase
+from huey.utils import time_clock
 
 
 class TestConsumer(Consumer):
@@ -35,8 +36,8 @@ def work_on_tasks(self, consumer, n=1, now=None):
 
     def schedule_tasks(self, consumer, now=None):
         scheduler = consumer._create_scheduler()
-        scheduler._next_loop = time.time() + 60
-        scheduler._next_periodic = time.time() - 60
+        scheduler._next_loop = time_clock() + 60
+        scheduler._next_periodic = time_clock() - 60
         scheduler.loop(now)
 
     def test_consumer_schedule_task(self):