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On Tue, May 08, 2018 at 03:02:05PM -0400, Doug Hellmann wrote:
> Excerpts from Matthew Treinish's message of 2018-05-08 13:55:43 -0400:
> > On Tue, May 08, 2018 at 01:34:11PM -0400, Doug Hellmann wrote:
> > > 
> > > (added [glance] subject tag)
> > > 
> > > Excerpts from Matthew Treinish's message of 2018-05-08 12:22:56 -0400:
> > > > On Tue, May 08, 2018 at 05:01:36PM +0100, Graham Hayes wrote:
> > > > > On 08/05/18 16:53, Doug Hellmann wrote:
> > > > > > Excerpts from Graham Hayes's message of 2018-05-08 16:28:46 +0100:
> 
> [snip]
> 
> > > > > Glance - Has issues with image upload + uwsgi + eventlet [1]
> > > > 
> > > > This actually is a bit misleading. Glance works fine with image upload and uwsgi.
> > > > That's the only configuration of glance in a wsgi app that works because
> > > > of chunked transfer encoding not being in the WSGI protocol. [2] uwsgi provides
> > > > an alternate interface to read chunked requests which enables this to work.
> > > > If you look at the bugs linked off that release note about image upload
> > > > you'll see they're all fixed.
> > > 
> > > Is this documented somewhere?
> > 
> > The wsgi limitation or the glance usage? I wrote up a doc about running under
> > apache when I added the uwsgi chunked transfer encoding support to glance about
> > running glance under apache here:
> > 
> > https://docs.openstack.org/glance/latest/admin/apache-httpd.html
> > 
> > Which includes how you have to configure things to get it working and a section
> > on why mod_wsgi doesn't work.
> 
> I meant the glance usage so it sounds like you've covered the docs
> for that. Thanks!
> 
> > > > The issues glance has with running in a wsgi app are related to it's use of
> > > > async tasks via taskflow. (which includes the tasks api and image import stuff)
> > > > This shouldn't be hard to fix, and I've had patches up to address these for
> > > > months:
> > > > 
> > > > https://review.openstack.org/#/c/531498/
> > > > https://review.openstack.org/#/c/549743/
> > > > 
> > > > Part of the issue is that there is no api driven testing for these async api
> > > > functions or any documented way to test them. Which is why I marked the 2nd
> > > > one WIP, since I have no method to test it and after asking several times
> > > > for a test case or some other method to validate these APIs without an answer.
> > > 
> > > It would be helpful if some of this detail made its way into the glance
> > > section of https://wiki.openstack.org/wiki/Python3#Python_3_Status_of_OpenStack_projects
> > 
> > It really doesn't have anything to do with Python 3 though since the bug with
> > glance's taskflow usage is on both py2 and py3. In fact we're already running
> > glance under uwsgi in the gate with python 3 today for the dsvm py3 jobs. The
> > reason these bugs haven't come up there is because there is no test coverage
> > for any of these async APIs. But I can add it to the wiki later today.
> 
> Will it block us from moving glance to python 3 if we drop the WSGI
> code from oslo.service so that the only way to deploy is behind
> some other WSGI server?
> 

It shouldn't be a blocker, the wsgi entrypoint just uses paste to expose the
wsgi app directly:

https://github.com/openstack/glance/blob/master/glance/common/wsgi_app.py#L59-L67

oslo.service doesn't come into play in that code path. So it won't block
the deploying with uwsgi model. The bugs addressed by the 2 patches I referenced
above will still be present though.

Although, I don't think glance uses oslo.service even in the case where it's
using the standalone eventlet server. It looks like it launches eventlet.wsgi
directly:

https://github.com/openstack/glance/blob/master/glance/common/wsgi.py

and I don't see oslo.service in the requirements file either:

https://github.com/openstack/glance/blob/master/requirements.txt

-Matt Treinish
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