Scheduler: Preserve period offset on restarts.

Partial fix for GH-397.

plugins/Scheduler/plugin.py

@@ -29,6 +29,7 @@
 
 import time
 import os
+import math
 import shutil
 import tempfile
 
@@ -56,6 +57,14 @@ def __init__(self, irc):
         self._restoreEvents(irc)
         world.flushers.append(self._flush)
 
+    def _getNextRunIn(self, first_run, now, period):
+        next_run_in = period - ((now - first_run) % period)
+        if next_run_in < 5:
+            # don't run immediatly, it might overwhelm the bot on
+            # startup.
+            next_run_in += period
+        return next_run_in
+
     def _restoreEvents(self, irc):
         try:
             pkl = open(filename, 'rb')
@@ -82,8 +91,21 @@ def _restoreEvents(self, irc):
                     self._add(ircobj, event['msg'],
                               event['time'], event['command'], n)
                 elif event['type'] == 'repeat': # repeating event
+                    now = time.time()
+                    first_run = event.get('first_run')
+                    if first_run is None:
+                        # old DBs don't have a "first_run"; let's take "now" as
+                        # first_run.
+                        first_run = now
+
+                    # Preserve the offset over restarts; eg. if event['time']
+                    # is 24hours, we want to keep running the command at the
+                    # same time of day.
+                    next_run_in = self._getNextRunIn(
+                        first_run, now, event['time'])
+
                     self._repeat(ircobj, event['msg'], name,
-                                 event['time'], event['command'], False)
+                                 event['time'], event['command'], first_run, next_run_in)
             except AssertionError as e:
                 if str(e) == 'An event with the same name has already been scheduled.':
                     # we must be reloading the plugin, event is still scheduled
@@ -166,14 +188,24 @@ def remove(self, irc, msg, args, id):
             irc.error(_('Invalid event id.'))
     remove = wrap(remove, ['lowered'])
 
-    def _repeat(self, irc, msg, name, seconds, command, now=True):
+    def _repeat(self, irc, msg, name, seconds, command, first_run=None, next_run_in=None):
         f = self._makeCommandFunction(irc, msg, command, remove=False)
-        id = schedule.addPeriodicEvent(f, seconds, name, now)
+        f_wrapper = schedule.schedule.makePeriodicWrapper(f, seconds, name)
+        if next_run_in is None:
+            assert first_run is None
+            # run immediately
+            id = f_wrapper()
+            first_run = time.time()
+        else:
+            assert first_run is not None
+            id = schedule.addEvent(f_wrapper, time.time() + next_run_in, name)
         assert id == name
         self.events[name] = {'command':command,
                              'msg':msg,
                              'time':seconds,
-                             'type':'repeat'}
+                             'type':'repeat',
+                             'first_run': first_run,
+                             }
 
     @internationalizeDocstring
     def repeat(self, irc, msg, args, name, seconds, command):

plugins/Scheduler/test.py

@@ -122,25 +122,37 @@ def testSinglePersistence(self):
 
     def testRepeatPersistence(self):
         self.assertRegexp(
-            'scheduler repeat repeater 5 echo testRepeat',
+            'scheduler repeat repeater 20 echo testRepeat',
             'testRepeat')
 
         self.assertNotError('unload Scheduler')
         schedule.schedule.reset()
-        timeFastForward(20)
+        timeFastForward(30)
         self.assertNoResponse(' ', timeout=1)
 
         self.assertNotError('load Scheduler')
-        self.assertNoResponse(' ', timeout=1)
-        timeFastForward(2)
-        self.assertNoResponse(' ', timeout=1)
-        timeFastForward(2)
-        self.assertResponse(' ', 'testRepeat')
+        self.assertNoResponse(' ', timeout=1) # T+30 to T+31
+        timeFastForward(5)
+        self.assertNoResponse(' ', timeout=1) # T+36 to T+37
+        timeFastForward(5)
+        self.assertResponse(' ', 'testRepeat', timeout=1) # T+42
 
-        timeFastForward(3)
+        timeFastForward(15)
+        self.assertNoResponse(' ', timeout=1) # T+57 to T+58
+        timeFastForward(5)
+        self.assertResponse(' ', 'testRepeat', timeout=1) # T+64
+
+        self.assertNotError('unload Scheduler')
+        schedule.schedule.reset()
+        timeFastForward(20)
         self.assertNoResponse(' ', timeout=1)
-        timeFastForward(2)
-        self.assertResponse(' ', 'testRepeat')
+
+        self.assertNotError('load Scheduler')
+        self.assertNoResponse(' ', timeout=1) # T+85 to T+86
+        timeFastForward(10)
+        self.assertNoResponse(' ', timeout=1) # T+95 to T+96
+        timeFastForward(10)
+        self.assertResponse(' ', 'testRepeat', timeout=1) # T+106
 
 
 

src/schedule.py

@@ -108,19 +108,27 @@ def rescheduleEvent(self, name, t):
         f = self.removeEvent(name)
         self.addEvent(f, t, name=name)
 
-    def addPeriodicEvent(self, f, t, name=None, now=True, args=[], kwargs={},
-            count=None):
-        """Adds a periodic event that is called every t seconds."""
-        def wrapper(count):
+    def makePeriodicWrapper(
+            self, f, t, name=None, args=[], kwargs={}, count=None):
+        """Returns a function that will run and re-schedule itself every t
+        seconds."""
+        def wrapper():
+            nonlocal count
             try:
                 f(*args, **kwargs)
             finally:
                 # Even if it raises an exception, let's schedule it.
-                if count[0] is not None:
-                    count[0] -= 1
-                if count[0] is None or count[0] > 0:
+                if count is not None:
+                    count -= 1
+                if count is None or count > 0:
                     return self.addEvent(wrapper, time.time() + t, name)
-        wrapper = functools.partial(wrapper, [count])
+        return wrapper
+
+    def addPeriodicEvent(
+            self, f, t, name=None, now=True, args=[], kwargs={}, count=None):
+        """Adds a periodic event that is called every t seconds."""
+        wrapper = self.makePeriodicWrapper(
+            f, t, name, args, kwargs, count)
         if now:
             return wrapper()
         else: