# HG changeset patch
# User Ludovic Chabant <ludovic@chabant.com>
# Date 1396157287 25200
# Node ID c6ec6096bd9509b7cfbf4ef2ff7e8026981b4e06
# Parent  8e3f8e34090f93918d710165ce0cd3906efc802c
Simpler out-of-the-box support for background updates.

Now by default Celery uses an SQLite broker, with storage in the `.wiki`
directory. This makes it possible to support async updates by simply passing
`--usetasks` to `wk runserver`, while also running `wk runtasks` in a different
process.

diff -r 8e3f8e34090f -r c6ec6096bd95 wikked/commands/web.py
--- a/wikked/commands/web.py	Fri Mar 28 23:33:00 2014 -0700
+++ b/wikked/commands/web.py	Sat Mar 29 22:28:07 2014 -0700
@@ -1,4 +1,6 @@
 import os
+import os.path
+import imp
 import logging
 from wikked.commands.base import WikkedCommand, register_command
 
@@ -20,6 +22,11 @@
         parser.add_argument('--port',
                 help="The port to use",
                 default=5000)
+        parser.add_argument('--usetasks',
+                help="Use background tasks for updating the wiki after a "
+                     "page has been edited. You will have to run "
+                     "`wk runtasks` at the same time as `wk runserver`.",
+                action='store_true')
         parser.add_argument('-d', '--dev',
                 help="Use development mode. "
                      "This makes Wikked use development assets (separate and "
@@ -33,9 +40,15 @@
         # TODO: make the Flask initialization more clever.
         os.chdir(ctx.params.root)
 
+        # Setup some settings that need to be set before the app is created.
+        import wikked.settings
+        if ctx.args.usetasks:
+            wikked.settings.WIKI_ASYNC_UPDATE = True
+
+        # Create/import the app.
         from wikked.web import app
 
-        # Setup the app.
+        # Setup other simpler settings.
         if ctx.args.dev:
             app.config['DEV_ASSETS'] = True
         app.config['WIKI_AUTO_RELOAD'] = True
@@ -53,3 +66,43 @@
                 use_debugger=debug_mode,
                 use_reloader=debug_mode)
 
+
+@register_command
+class RunTasksCommand(WikkedCommand):
+    def __init__(self):
+        super(RunTasksCommand, self).__init__()
+        self.name = 'runtasks'
+        self.description = "Runs the tasks to update the wiki in the background."
+
+    def setupParser(self, parser):
+        pass
+
+    def run(self, ctx):
+        # Import the Celery app and update its configuration with the same
+        # stuff as what the Flask app got.
+        from wikked.tasks import celery_app
+
+        celery_app.conf.update(BROKER_URL='sqla+sqlite:///%(root)s/.wiki/broker.db')
+        config_path = os.path.join(ctx.params.root, '.wiki', 'app.cfg')
+        if os.path.isfile(config_path):
+            obj = self._loadConfig(config_path)
+            celery_app.conf.update(obj.__dict__)
+        celery_app.conf.BROKER_URL = celery_app.conf.BROKER_URL % (
+                { 'root': ctx.params.root })
+
+        os.chdir(os.path.join(os.path.dirname(__file__), '..', '..'))
+        argv = ['celery', 'worker', '-A', 'wikked.tasks']
+        if ctx.args.debug:
+            argv += ['-l', 'DEBUG']
+        celery_app.start(argv)
+
+    def _loadConfig(self, path):
+        d = imp.new_module('config')
+        d.__file__ = path
+        try:
+            with open(path) as config_file:
+                exec(compile(config_file.read(), path, 'exec'), d.__dict__)
+        except IOError as e:
+            e.strerror = 'Unable to load Flask/Celery configuration file (%s)' % e.strerror
+            raise
+        return d
diff -r 8e3f8e34090f -r c6ec6096bd95 wikked/web.py
--- a/wikked/web.py	Fri Mar 28 23:33:00 2014 -0700
+++ b/wikked/web.py	Sat Mar 29 22:28:07 2014 -0700
@@ -23,7 +23,7 @@
 app.config.setdefault('UPDATE_WIKI_ON_START', True)
 app.config.setdefault('WIKI_AUTO_RELOAD', False)
 app.config.setdefault('WIKI_ASYNC_UPDATE', False)
-app.config.setdefault('BROKER_URL', 'amqp://')
+app.config.setdefault('BROKER_URL', 'sqla+sqlite:///%(root)s/.wiki/broker.db')
 
 
 # Find the wiki root, and further configure the app if there's a
@@ -132,10 +132,14 @@
     from wikked.tasks import celery_app, update_wiki
 
     # Configure Celery.
+    app.config['BROKER_URL'] = app.config['BROKER_URL'] % (
+        { 'root': wiki_root })
     celery_app.conf.update(app.config)
+    app.logger.debug("Using Celery broker: %s" % app.config['BROKER_URL'])
 
     # Make the wiki use the background update task.
     def async_updater(wiki):
+        app.logger.debug("Running update task on Celery.")
         update_wiki.delay(wiki.root)
     app.wiki_updater = async_updater