Latest version is not working with Google App Engine

[magoarcano]

Hi
Since the 4.x it's not working for Google App Engine development server, because now it doesn't accept a multiprocess environment.
I get the message:

/pyramid_debugtoolbar/toolbar.py:214: UserWarning: 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

Version 3.0.5 was working great.

[digitalresistor]

That warning is correct. The debugtoolbar never worked with a forking/multiprocess web server because you would only see some of the requests/some of the items to debug because a request may or may not be scheduled on the same process.

Unfortunately this is not a use case we support. If you are absolutely sure that the GAE development server does not fork and is not multi-process, you may want to write a small WSGI middleware that removes the flag set on the WSGI environment that says it is.

[magoarcano]

Thanks.

If I hack the code a little I can make it work for GAE.

First I comment that block of code:

#         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)

Secondly, I have to bypass process_response_deferred() at headers.HeaderDebugPanel (new in version 4.x):

def finished_callback(request):
            pass

And finally VersionDebugPanel (also in version 3.x):

def _get_platform_name(self):
        return "platform.platform() para GAE" #platform.platform()

Maybe it's not working 100% ok because it's multiprocess server. For now it's enough for me.

Theoretically there is a way for serializing the requests by disabling the dev_appserver multi-threading and multi-processing support, with a flag. I will try it.

[digitalresistor]

multi-threading is fine. multi-processing does not work correctly with the debugtoolbar.

[mmerickel]

I guess I agree that the warning is helping you discover that GAE is possibly breaking the toolbar in subtle ways. However I don't see any reason your fixes for the header and versions panels are required so I don't fully understand your issue.

If you can stop GAE from running with multiple processes and then open actual issues with the panel as a result then we should try to fix them. Until then there's nothing I can do on my end.