Comment 17 for bug 1771114

Reviewed: https://review.opendev.org/c/openstack/charm-keystone/+/885991
Committed: https://opendev.org/openstack/charm-keystone/commit/64e5347b4b4ba2ad3b8fa53dbc7fa6dae8c42880
Submitter: "Zuul (22348)"
Branch: stable/2023.1

commit 64e5347b4b4ba2ad3b8fa53dbc7fa6dae8c42880
Author: Edward Hope-Morley <email address hidden>
Date: Wed Jun 7 14:14:14 2023 +0100

    Make role-cache-expiration configurable

    We use a default expiration_time (dogpile-expiration-time)
    of 600s which means that role assignments will take up to
    this amount of time before all caches are updated to
    reflect changes. This may not be suitable for some clouds
    that make frequent changes to role assignments and lowering
    the global value is not recommended so this overrides the
    [role] cache_time to a more appropriate value and also
    makes it configurable. We leave default value as None so
    that the global value is still inherited but this at least
    allows it to be customised.

    Change-Id: I49e46e010c543f831959581b2122f59068f2c07b
    Closes-Bug: #1771114
    (cherry picked from commit 0cb787bb9d2e8a5c87821646f2387ae1f2dcd8a0)