[openstack-dev] [TC][Keystone] Rehashing the Pecan/Falcon/other WSGI debate

Jamie Lennox jamielennox at redhat.com
Sat May 2 01:16:41 UTC 2015


Hi all, 

At around the time Barbican was applying for incubation there was a
discussion about "supported" WSGI frameworks. From memory the decision
at the time was that Pecan was to be the only supported framework and
that for incubation Barbican had to convert to Pecan (from Falcon).

Keystone is looking to ditch our crusty old, home-grown wsgi layer for
an external framework and both Pecan and Falcon are in global
requirements. 

In the experimenting I've done Pecan provides a lot of stuff we don't
need and some that just gets in the way. To call out a few:
 * the rendering engine really doesn't make sense for us, for APIs, and
where we are often returning different data (not just different views or
data) based on Content-Type. 
 * The security enforcement within Pecan does not really mesh with how
we enforce policy, nor does the way we build controller objects per
resource. It seems we will have to build this for ourselves on top of
pecan

and there are just various other niggles. 

THIS IS NOT SUPPOSED TO START A DEBATE ON THE VIRTUES OF EACH FRAMEWORK.

Everything I've found can be dealt with and pecan will be a vast
improvement over what we use now. I have also not written a POC with
Falcon to know that it will suit any better.

My question is: Does the ruling that Pecan is the only WSGI framework
for OpenStack stand? I don't want to have 100s of frameworks in the
global requirements, but given falcon is already there iff a POC
determines that Falcon is a better fit for keystone can we use it? 


Thanks, 

Jamie 




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