update-status hook executes a2enmod unnecessarily

[Nobuto Murata]

This is not a high importance, but similar to LP: #1907171. I see the output from a2enmod always when running update-status hooks.

$ juju run --unit ceph-radosgw/0 -- time hooks/update-status
Considering dependency setenvif for ssl:
Module setenvif already enabled
Considering dependency mime for ssl:
Module mime already enabled
Considering dependency socache_shmcb for ssl:
Module socache_shmcb already enabled
Module ssl already enabled
Module proxy already enabled
Considering dependency proxy for proxy_http:
Module proxy already enabled
Module proxy_http already enabled
Module headers already enabled
active
active
active

real 0m3.377s
user 0m2.690s
sys 0m0.793s

[Nobuto Murata (nobuto)]

a2enmod is a part of ApacheSSLContext fwiw.

[Nobuto Murata (nobuto)]

Here is the list of affected charms after a quick scan. It looks like all or most of "classic" openstack charms.

ceph-radosgw
cinder
glance
heat
keystone
neutron-api
nova-cloud-controller
openstack-dashboard

[Alex Kavanagh (ajkavanagh)]

The problem is in charm-helpers, in contrib/openstack/context.py in the ApacheSSLContext as Nobutu notes above.

The problem is in the design of Contexts which eagerly do all their computations at module load time (due to the contexts variable being a global variable in the module).

However, lazily loading the contexts may or may not fix this problem as (in some charms) the contexts are used as part of the assess_status message generation.

The ACTUAL solution to this is to defer each of the Context class __call__() function calls until they are first accessed as part of the larger dictionary of contexts. Which might need a bit of re-engineering of how the context is set up, but not how it gets used. The other, is simply to not use contexts in the update_status generation (and this would need to be determined on a case by case basis).

For the ceph-radosgw charm it calls "assess_status(CONFIGS)" on every single call, so it would need a re-design of whether to use the ApacheSSLContext for assess_status.