An environment variable to transition towards removing global variables

mediagoblin/app.py

@@ -42,6 +42,8 @@ from mediagoblin.tools.pluginapi import PluginManager, hook_transform
 from mediagoblin.tools.crypto import setup_crypto
 from mediagoblin.auth.tools import check_auth_enabled, no_auth_logout
 
+from mediagoblin.tools.transition import DISABLE_GLOBALS
+
 
 _log = logging.getLogger(__name__)
 
@@ -150,9 +152,14 @@ class MediaGoblinApp(object):
         # certain properties need to be accessed globally eg from
         # validators, etc, which might not access to the request
         # object.
+        #
+        # Note, we are trying to transition this out;
+        # run with environment variable DISABLE_GLOBALS=true
+        # to work on it
         #######################################################
 
-        setup_globals(app=self)
+        if not DISABLE_GLOBALS:
+            setup_globals(app=self)
 
         # Workbench *currently* only used by celery, so this only
         # matters in always eager mode :)
@@ -174,12 +181,7 @@ class MediaGoblinApp(object):
         # --------------
 
         # Is a context provided?
-        if ctx is not None:
+        if ctx is None:
-            # Do special things if this is a request
-            if isinstance(ctx, Request):
-                ctx = self._request_only_gen_context(ctx)
-
-        else:
             ctx = Context()
         
         # Attach utilities
@@ -192,6 +194,11 @@ class MediaGoblinApp(object):
         ctx.db = self.db
         ctx.staticdirect = self.staticdirector
 
+        # Do special things if this is a request
+        # --------------------------------------
+        if isinstance(ctx, Request):
+            ctx = self._request_only_gen_context(ctx)
+
         return ctx
 
     def _request_only_gen_context(self, request):

mediagoblin/db/base.py

@@ -19,8 +19,10 @@ from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import scoped_session, sessionmaker, object_session
 from sqlalchemy import inspect
 
-Session = scoped_session(sessionmaker())
+from mediagoblin.tools.transition import DISABLE_GLOBALS
 
+if not DISABLE_GLOBALS:
+    Session = scoped_session(sessionmaker())
 
 
 class GMGTableBase(object):
@@ -28,7 +30,8 @@ class GMGTableBase(object):
     def _session(self):
         return inspect(self).session
 
-    query = Session.query_property()
+    if not DISABLE_GLOBALS:
+        query = Session.query_property()
 
     def get(self, key):
         return getattr(self, key)
@@ -38,9 +41,10 @@ class GMGTableBase(object):
         return getattr(self, key)
 
     def save(self, commit=True):
-        sess = object_session(self)
+        sess = self._session
-        if sess is None:
+        if sess is None and not DISABLE_GLOBALS:
             sess = Session()
+        assert sess is not None, "Can't save, %r has a detached session" % self
         sess.add(self)
         if commit:
             sess.commit()
@@ -49,7 +53,7 @@ class GMGTableBase(object):
 
     def delete(self, commit=True):
         """Delete the object and commit the change immediately by default"""
-        sess = object_session(self)
+        sess = self._session
         assert sess is not None, "Not going to delete detached %r" % self
         sess.delete(self)
         if commit:

mediagoblin/tools/transition.py

@@ -0,0 +1,21 @@
+# GNU MediaGoblin -- federated, autonomous media hosting
+# Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+import os
+
+# one global to disable them all
+DISABLE_GLOBALS = os.environ.get("DISABLE_GLOBALS", "false").lower() == "true"