The thread local which stores the request context is not green

[Radoslav Gerganov]

nova-compute imports oslo.context before calling monkey_patch():

(Pdb) bt
  /usr/local/bin/nova-compute(6)<module>()
-> from nova.cmd.compute import main
  /opt/stack/nova/nova/__init__.py(33)<module>()
-> import oslo_service # noqa
  /usr/local/lib/python2.7/dist-packages/oslo_service/__init__.py(17)<module>()
-> from oslo_log import log as logging
  /usr/local/lib/python2.7/dist-packages/oslo_log/log.py(48)<module>()
-> from oslo_log import formatters
  /usr/local/lib/python2.7/dist-packages/oslo_log/formatters.py(28)<module>()
-> from oslo_context import context as context_utils
> /usr/local/lib/python2.7/dist-packages/oslo_context/context.py(40)<module>()
-> _request_store = threading.local()

which makes the global thread-local variable (_request_store) not green. So instead of having request context per green thread, we have one context for all green threads which is overwritten every time a new context is created.

This is regression from this patch:

https://review.openstack.org/#/c/434327/

which imports oslo.service before eventlet

[Matt Riedemann (mriedem)]

Someone said the same in this change:

https://review.openstack.org/#/c/582332/

"""
Hello melanie, I meet the same problem about request-id in log.
I think this bug is similar to cinder bug https://bugs.launchpad.net/cinder/+bug/1743461 as Rikimaru Honjo says.
In his patch, eventlet.monkey_patch() must before import oslo_log (actually before import oslo_context).

In nova, we do eventlet.monkey_patch() in nova/cmd/__init__.py but import oslo_service in nova/__init__.py,
and in oslo_service will import oslo log.

In my environment, I delete the monkey_patch() in nova/cmd/__init__.py and put it to nova/__init__.py before oslo_service.
In this way, the request-id (including the periodic task) will not be replaced by other processes.

I think this maybe more suitable to close bug#1773102.
Tanks.
"""