Memcached token backend should work with any timezone

[You Yamagata]

In configuration document, it looks like following configuration are required with memcache token backend.

- Memcached server's timezone is set to UTC.
- Timezone of both Memcached and Keystone server should be same.
So Keystone server's timezone is also set to UTC.

http://docs.openstack.org/developer/keystone/configuration.html#memcached-and-system-time

I guess this limitation is caused by incorrect expiration time is set when tokens are generated.

backends/memcache.py call utils.unixtime() and it calls time.mktime().
time.mktime() return localtime, not UTC, so its value depends on time zone.

In my tests, if keystone server runs with UTC + N (N>=1), token authorization failed.

# run keystone server with UTC+1
> env TZ='UTC-1' tools/with_venv.sh bin/keystone-all
# get token
> env TZ=UTC tools/with_venv.sh keystone .. token-get
+-----------+----------------------------------+
| Property | Value |
+-----------+----------------------------------+
| expires | 2013-09-05T08:38:14Z |
| id | fecd5f9e1c1842f0a60d86a07584fca4 |
| tenant_id | 7b1abdb5213a4962bcaf04a7e0881a91 |
| user_id | 03a2d2e23ff94bfa908856d2c1081110 |
+-----------+----------------------------------+
# use token
> env TZ=UTC curl -H "X-Auth-Token:$TOKEN" http://localhost:5000/v2.0/tenants
{"error": {"message": "Could not find token, fecd5f9e1c1842f0a60d86a07584fca4.", "code": 401, "title": "Unauthorized"}}

[Dolph Mathews (dolph)]

https://review.openstack.org/#/c/40378/

[Alan Pevec (apevec)]

Proposed for stable/grizzly
https://review.openstack.org/51995

[Morgan Fainberg (mdrnstm)]

Grizzly is EOL, wont fix the grizzly branch at this point. Havana and beyond have this fix.