glance/bin/glance-cache-prefetcher
Mark McLoughlin 57c4e9b6c6 Convert glance to use the new cfg module
The changes here are substantial and widespread, but in summary:

  - We use cfg to parse the CLI and config files, rather than optparse
    and PasteDeploy

  - A schema is defined for all configuration options close to the code
    which uses the option

  - 2 ConfigOpts sub-classes are added to config.py basically just
    defining how to find config files; this means we can now use e.g.
    glance.conf for base config values which glance-api.conf can
    override

  - load_paste_app() is changed to load the paste app from the last
    config file in the stack and pass the app the ConfigOpts instance

  - The generic app and filter factories in wsgi.py are modified to
    pass a ConfigOpts instance to the apps and filters

  - A ConfigOpts subclass is added for the unit tests which writes out
    config values to a temporary config file and uses cfg to parse that

I've tried to keep the switch as unobtrusive as possible leaving further
cleanups for later e.g.

  - Moving PasteDeploy config out of the config files - I think it would
    be good to aim for having users modify the PasteDeploy config files
    only in fairly rare circumstances. To achieve this, we might define
    a number of common pipelines in the PasteDeploy config and allow
    the user to choose between those pipelines in the glance config.

  - We should add help strings to all the opts, even just for the sake
    of documenting them

  - We should move a bunch of the options into groups - e.g. all the
    rabbit options

  - We no longer rely on config files for default values, so the default
    config files could contain nothing but comments - i.e. explaining
    each option and showing what the default for it is - making it
    obvious where a user has explicitly set a value

There are a couple of behavioural changes which I don't think are
signifcant but are worth mentioning:

  - We used to support passing a config file as a positional argument
    but don't anymore; AFAICT, it was only used by glance-manage when
    launching servers and I've changed that to pass --config-file

  - log_opt_values() doesn't log unknown opts, so won't log any values
    for opts which get registered at runtime later

Change-Id: Iafa998a2a8d860f1ad57e2cd2afee69686ed58ba
2011-12-08 22:32:52 +00:00

52 lines
1.6 KiB
Python
Executable File

#!/usr/bin/env python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2011 OpenStack LLC.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""
Glance Image Cache Pre-fetcher
This is meant to be run from the command line after queueing
images to be pretched.
"""
import gettext
import os
import sys
# If ../glance/__init__.py exists, add ../ to Python search path, so that
# it will override what happens to be installed in /usr/(local/)lib/python...
possible_topdir = os.path.normpath(os.path.join(os.path.abspath(sys.argv[0]),
os.pardir,
os.pardir))
if os.path.exists(os.path.join(possible_topdir, 'glance', '__init__.py')):
sys.path.insert(0, possible_topdir)
gettext.install('glance', unicode=1)
from glance.common import config
if __name__ == '__main__':
try:
conf = config.GlanceCacheConfigOpts()
conf()
app = config.load_paste_app(conf, 'glance-prefetcher')
app.run()
except RuntimeError, e:
sys.exit("ERROR: %s" % e)