From 0332d0ca5566102b4eba6f04a660ed3f0b7e62bb Mon Sep 17 00:00:00 2001
From: Max Goodman <max@reddit.com>
Date: Tue, 7 Feb 2012 12:26:30 -0800
Subject: [PATCH] Fix import loop and move plugins collection into its own
 class.

Loading plugin controller modules at the bottom of
controllers/__init__.py led to a circular dependency. Registering
controllers via decorator allows controllers/__init__.py to load
completely before plugin controllers are loaded.
---
 r2/r2/config/environment.py   |  4 +--
 r2/r2/config/middleware.py    |  3 ++-
 r2/r2/config/routing.py       |  2 +-
 r2/r2/controllers/__init__.py |  7 +++---
 r2/r2/lib/plugin.py           | 47 ++++++++++++++++++++++++++---------
 5 files changed, 44 insertions(+), 19 deletions(-)

diff --git a/r2/r2/config/environment.py b/r2/r2/config/environment.py
index 073dc3593..749d26b5d 100644
--- a/r2/r2/config/environment.py
+++ b/r2/r2/config/environment.py
@@ -33,7 +33,7 @@ from r2.config import routing
 import r2.lib.app_globals as app_globals
 from   r2.lib import  rpc
 import r2.lib.helpers
-from r2.lib.plugin import load_plugins
+from r2.lib.plugin import PluginLoader
 import r2.config as reddit_config
 
 from r2.templates import tmpl_dirs
@@ -58,7 +58,7 @@ def load_environment(global_conf={}, app_conf={}, setup_globals=True):
 
     config['pylons.h'] = r2.lib.helpers
 
-    config['r2.plugins'] = load_plugins(getattr(g, 'plugins', []))
+    config['r2.plugins'] = PluginLoader().load_plugins(getattr(g, 'plugins', []))
     config['routes.map'] = routing.make_map()
 
     #override the default response options
diff --git a/r2/r2/config/middleware.py b/r2/r2/config/middleware.py
index b5e9e48b1..437664dcc 100644
--- a/r2/r2/config/middleware.py
+++ b/r2/r2/config/middleware.py
@@ -515,6 +515,7 @@ class RedditApp(PylonsBaseWSGIApp):
         class_name = controller.capitalize() + 'Controller'
 
         __import__(self.package_name + '.controllers')
+        config['r2.plugins'].load_controllers()
         mycontroller = getattr(sys.modules[full_module_name], class_name)
         self.controller_classes[controller] = mycontroller
         return mycontroller
@@ -576,7 +577,7 @@ def make_app(global_conf, full_stack=True, **app_conf):
     static_cascade = [static_app, javascripts_app, app]
     if config['r2.plugins']:
         plugin_static_apps = Cascade([StaticURLParser(plugin.static_dir)
-                                      for plugin in config['r2.plugins'].itervalues()])
+                                      for plugin in config['r2.plugins']])
         static_cascade.insert(0, plugin_static_apps)
     app = Cascade(static_cascade)
 
diff --git a/r2/r2/config/routing.py b/r2/r2/config/routing.py
index 36f5be2ca..8785a11c0 100644
--- a/r2/r2/config/routing.py
+++ b/r2/r2/config/routing.py
@@ -31,7 +31,7 @@ def make_map():
     map = Mapper()
     mc = map.connect
 
-    for plugin in config['r2.plugins'].itervalues():
+    for plugin in config['r2.plugins']:
         plugin.add_routes(mc)
 
     admin_routes.add(mc)
diff --git a/r2/r2/controllers/__init__.py b/r2/r2/controllers/__init__.py
index 641256619..68a93660b 100644
--- a/r2/r2/controllers/__init__.py
+++ b/r2/r2/controllers/__init__.py
@@ -67,6 +67,7 @@ from admin import AdminController
 from redirect import RedirectController
 from ipn import IpnController
 
-from pylons import config
-for plugin in config['r2.plugins'].itervalues():
-    locals().update(plugin.load_controllers())
+def add_controller(controller):
+    assert controller.__name__ not in globals()
+    globals()[controller.__name__] = controller
+    return controller
diff --git a/r2/r2/lib/plugin.py b/r2/r2/lib/plugin.py
index 4de55cdc1..706caaa72 100644
--- a/r2/r2/lib/plugin.py
+++ b/r2/r2/lib/plugin.py
@@ -22,16 +22,39 @@ class Plugin(object):
     def add_routes(self, mc):
         pass
 
+    def load_controllers(self):
+        pass
 
-def load_plugins(plugin_names):
-    plugins = {}
-    for name in plugin_names:
-        try:
-            entry_point = pkg_resources.iter_entry_points('r2.plugin', name).next()
-        except StopIteration:
-            config['pylons.g'].log.warning('Unable to locate plugin "%s". Skipping.' % name)
-            continue
-        plugin_cls = entry_point.load()
-        plugin = plugins[name] = plugin_cls()
-        config['pylons.paths']['templates'].extend(plugin.template_dirs)
-    return plugins
+
+class PluginLoader(object):
+    def __init__(self):
+        self.plugins = {}
+        self.controllers_loaded = False
+
+    def __len__(self):
+        return len(self.plugins)
+
+    def __iter__(self):
+        return self.plugins.itervalues()
+
+    def __getitem__(self, key):
+        return self.plugins[key]
+
+    def load_plugins(self, plugin_names):
+        for name in plugin_names:
+            try:
+                entry_point = pkg_resources.iter_entry_points('r2.plugin', name).next()
+            except StopIteration:
+                config['pylons.g'].log.warning('Unable to locate plugin "%s". Skipping.' % name)
+                continue
+            plugin_cls = entry_point.load()
+            plugin = self.plugins[name] = plugin_cls()
+            config['pylons.paths']['templates'].extend(plugin.template_dirs)
+        return self
+
+    def load_controllers(self):
+        if self.controllers_loaded:
+            return
+        for plugin in self:
+            plugin.load_controllers()
+        self.controllers_loaded = True