Scheduler: add scheduled task persistence.

The list of tasks scheduled with the Scheduler plugin is now saved
on exit, and restored upon restart.

Previously all scheduled tasks would be forgotten upon bot restart,
which was undesirable behavior.

plugins/Scheduler/plugin.py

@@ -28,18 +28,73 @@
 ###
 
 import time
+import os
+import shutil
+import tempfile
+import cPickle as pickle
 
 import supybot.conf as conf
 import supybot.utils as utils
 from supybot.commands import *
 import supybot.schedule as schedule
 import supybot.callbacks as callbacks
+import supybot.world as world
+
+datadir = conf.supybot.directories.data()
+filename = conf.supybot.directories.data.dirize('Scheduler.pickle')
 
 class Scheduler(callbacks.Plugin):
     def __init__(self, irc):
         self.__parent = super(Scheduler, self)
         self.__parent.__init__(irc)
         self.events = {}
+        self._restoreEvents(irc)
+        world.flushers.append(self._flush)
+
+    def _restoreEvents(self, irc):
+        try:
+            pkl = open(filename, 'rb')
+            try:
+                eventdict = pickle.load(pkl)
+            except Exception, e:
+                self.log.debug('Unable to load pickled data: %s', e)
+                return
+            finally:
+                pkl.close()
+        except IOError, e:
+            self.log.debug('Unable to open pickle file: %s', e)
+            return
+        try:
+            for name, event in eventdict.iteritems():
+                ircobj = callbacks.ReplyIrcProxy(irc, event['msg'])
+                if event['type'] == 'single': # non-repeating event
+                    self._add(ircobj, event['msg'],
+                              event['time'], event['command'])
+                elif event['type'] == 'repeat': # repeating event
+                    self._repeat(ircobj, event['msg'], name,
+                                 event['time'], event['command'])
+        except AssertionError, e:
+            if str(e) == 'An event with the same name has already been scheduled.':
+                pass # we must be reloading the plugin
+            else:
+                raise
+                                     
+    def _flush(self):
+        try:
+            pklfd, tempfn = tempfile.mkstemp(suffix='scheduler', dir=datadir)
+            pkl = os.fdopen(pklfd, 'wb')
+            try:
+                pickle.dump(self.events, pkl)
+            except Exception, e:
+                self.log.warning('Unable to store pickled data: %s', e)
+            pkl.close()
+            shutil.move(tempfn, filename)
+        except (IOError, shutil.Error), e:
+            self.log.warning('File error: %s', e)
+
+    def die(self):
+        world.flushers.remove(self._flush)
+        self.__parent.die()
 
     def _makeCommandFunction(self, irc, msg, command, remove=True):
         """Makes a function suitable for scheduling from command."""
@@ -52,6 +107,16 @@ class Scheduler(callbacks.Plugin):
             self.Proxy(irc.irc, msg, tokens)
         return f
 
+    def _add(self, irc, msg, t, command):
+        f = self._makeCommandFunction(irc, msg, command)
+        id = schedule.addEvent(f, t)
+        f.eventId = id
+        self.events[str(id)] = {'command':command,
+                                'msg':msg,
+                                'time':t,
+                                'type':'single'}
+        return id
+
     def add(self, irc, msg, args, seconds, command):
         """<seconds> <command>
 
@@ -61,10 +126,8 @@ class Scheduler(callbacks.Plugin):
         command was given in (with no prefixed nick, a consequence of using
         echo).  Do pay attention to the quotes in that example.
         """
-        f = self._makeCommandFunction(irc, msg, command)
-        id = schedule.addEvent(f, time.time() + seconds)
-        f.eventId = id
-        self.events[str(id)] = command
+        t = time.time() + seconds
+        id = self._add(irc, msg, t, command)
         irc.replySuccess(format('Event #%i added.', id))
     add = wrap(add, ['positiveInt', 'text'])
 
@@ -88,6 +151,15 @@ class Scheduler(callbacks.Plugin):
             irc.error('Invalid event id.')
     remove = wrap(remove, ['lowered'])
 
+    def _repeat(self, irc, msg, name, seconds, command):
+        f = self._makeCommandFunction(irc, msg, command, remove=False)
+        id = schedule.addPeriodicEvent(f, seconds, name)
+        assert id == name
+        self.events[name] = {'command':command,
+                             'msg':msg,
+                             'time':seconds,
+                             'type':'repeat'}
+
     def repeat(self, irc, msg, args, name, seconds, command):
         """<name> <seconds> <command>
 
@@ -100,10 +172,7 @@ class Scheduler(callbacks.Plugin):
         if name in self.events:
             irc.error('There is already an event with that name, please '
                       'choose another name.', Raise=True)
-        self.events[name] = command
-        f = self._makeCommandFunction(irc, msg, command, remove=False)
-        id = schedule.addPeriodicEvent(f, seconds, name)
-        assert id == name
+        self._repeat(irc, msg, name, seconds, command)
         # We don't reply because the command runs immediately.
         # But should we?  What if the command doesn't have visible output?
         # irc.replySuccess()
@@ -118,8 +187,11 @@ class Scheduler(callbacks.Plugin):
         if L:
             L.sort()
             for (i, (name, command)) in enumerate(L):
-                L[i] = format('%s: %q', name, command)
+                L[i] = format('%s: %q', name, command['command'])
             irc.reply(format('%L', L))
+            irc.reply(schedule.schedule.schedule)
+            irc.reply(schedule.schedule.events)
+            irc.reply(schedule.schedule.counter)
         else:
             irc.reply('There are currently no scheduled commands.')
     list = wrap(list)