Split off the Tornado code into a separate process

(imported from commit 95dbd0f438cdba06d6e6c6c539a2a3d49c577cfd)

humbug/settings.py

@@ -84,6 +84,13 @@ if deployed:
     SESSION_COOKIE_SECURE = True
     CSRF_COOKIE_SECURE    = True
 
+# A shared secret, used to authenticate different parts of the app to each other.
+# FIXME: store this password more securely
+SHARED_SECRET = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'
+
+# URL where Django code posts to the Tornado code to notify of new messages
+NOTIFY_WAITING_CLIENTS_URL = 'http://localhost:9993/notify_waiting_clients'
+
 # List of callables that know how to import templates from various sources.
 TEMPLATE_LOADERS = (
     'django.template.loaders.filesystem.Loader',

humbug/urls.py

@@ -40,6 +40,9 @@ urlpatterns = patterns('',
     url(r'^static/(?P<path>.*)$', 'django.views.static.serve',
         {'document_root': os.path.join(settings.SITE_ROOT, '../zephyr/static-access-control')}),
 
+    # Used internally for communication between Django and Tornado processes
+    url(r'^notify_waiting_clients$', 'zephyr.views.notify_waiting_clients', name='notify_waiting_clients'),
+
     # Uncomment the admin/doc line below to enable admin documentation:
     # url(r'^admin/doc/', include('django.contrib.admindocs.urls')),
 

zephyr/management/commands/runtornado.py

@@ -84,14 +84,11 @@ class Command(BaseCommand):
             print "Tornado server is running at http://%s:%s/" % (addr, port)
             print "Quit the server with %s." % quit_command
 
-            from tornado.web import FallbackHandler
-            django_app = wsgi.WSGIContainer(WSGIHandler())
-
             try:
                 # Application is an instance of Django's standard wsgi handler.
                 application = web.Application([(r"/json/get_updates", AsyncDjangoHandler),
                                                (r"/api/v1/get_messages", AsyncDjangoHandler),
-                                               (r".*", FallbackHandler, dict(fallback=django_app)),
+                                               (r"/notify_waiting_clients", AsyncDjangoHandler),
                                                ], debug=django.conf.settings.DEBUG)
 
                 # start tornado web server in single-threaded mode

zephyr/models.py

@@ -11,6 +11,7 @@ import simplejson
 from django.db import transaction
 from zephyr.lib import bugdown
 from zephyr.lib.avatar import gravatar_hash
+import requests
 
 @cache_with_key(lambda self: 'display_recipient_dict:%d' % (self.id))
 def get_display_recipient(recipient):
@@ -81,6 +82,7 @@ class UserProfile(models.Model):
     api_key = models.CharField(max_length=32)
 
     # The user receives this message
+    # Called in the Tornado process
     def receive(self, message):
         global callback_table
 
@@ -292,8 +294,10 @@ def do_send_message(message, synced_from_mit=False, no_log=False):
         for user_profile in recipients:
             UserMessage(user_profile=user_profile, message=message).save()
 
-    for recipient in recipients:
-        recipient.receive(message)
+    requests.post(settings.NOTIFY_WAITING_CLIENTS_URL, data=[
+           ('secret',  settings.SHARED_SECRET),
+           ('message', message.id)]
+        + [('user',    user.id) for user in recipients])
 
 class Subscription(models.Model):
     userprofile = models.ForeignKey(UserProfile)

zephyr/views.py

@@ -446,6 +446,28 @@ def send_message_backend(request, user_profile, sender):
     return json_success()
 
 
+@asynchronous
+@csrf_exempt
+@require_post
+def notify_waiting_clients(request, handler):
+    # Check the shared secret.
+    # Also check the originating IP, at least for now.
+    if ((request.META['REMOTE_ADDR'] != '127.0.0.1')
+        or (request.POST.get('secret') != settings.SHARED_SECRET)):
+
+        handler.set_status(403)
+        handler.finish('Access denied')
+        return
+
+    # FIXME: better query
+    users   = [UserProfile.objects.get(id=user) for user in request.POST.getlist('user')]
+    message = Message.objects.get(id=request.POST['message'])
+
+    for user in users:
+        user.receive(message)
+
+    handler.finish()
+
 @login_required_api_view
 def api_get_public_streams(request, user_profile):
     streams = sorted([stream.name for stream in