Merge pull request #286 from mmerickel/warn-on-multiprocess

add a warning when the wsgi server is multiprocess

CHANGES.txt

@@ -32,6 +32,12 @@ Unreleased
   the top-level ``<li>`` tag has the id now.
   See https://github.com/Pylons/pyramid_debugtoolbar/pull/285
 
+- Emit a warning and disable the toolbar if the app is being served by
+  a forking / multiprocess wsgi server that sets
+  ``environ['wsgi.multiprocess']`` to ``True``. This should help avoid
+  confusing issues in certain deployments like gunicorn and uwsgi multiprocess
+  modes. See https://github.com/Pylons/pyramid_debugtoolbar/pull/286
+
 3.0.5 (2016-11-1)
 -----------------
 

pyramid_debugtoolbar/toolbar.py

@@ -1,5 +1,6 @@
 import sys
 import os
+import warnings
 
 from pyramid.exceptions import URLDecodeError
 from pyramid.httpexceptions import WSGIHTTPException
@@ -186,6 +187,14 @@ def toolbar_tween(request):
         ):
             return handler(request)
 
+        if request.environ.get('wsgi.multiprocess', False):
+            warnings.warn(
+                'pyramid_debugtoolbar has detected that the application is '
+                'being served by a forking / multiprocess web server. The '
+                'toolbar relies on global state to work and is not compatible '
+                'with this environment. The toolbar will be disabled.')
+            return handler(request)
+
         root_path = debug_toolbar_url(request, '', _app_url='')
         if p.startswith(root_path):
             # we know root_path will always have a trailing slash