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#!/use/bin/env python
#
# Constants.py: this file is part of the GRS suite
# Copyright (C) 2015 Anthony G. Basile
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import os
import sys
import configparser
from copy import deepcopy
class Constants():
""" Read a global configuration file and set/override constants for
each GRS spec. These constants are exported in the form:
CONST.repo_uris[x] contains the repo_uri for the xth GRS spec
etc.
Notice the 's' added to the list name to distinguish the list from
the constant it holds. Here the x is an integer corresponding to a
section in a global config file, which by default is located at
'/etc/grs/systes.conf'. This file is in configparser format and
each section introduces a new GRS namespace. The default values
for all possible constants in any given GRS namespace are defined
by the space[] dictionary below, but these can be overridden using
the item:value pairs from the section of any given GRS namespace.
E.g. Suppose /etc/grs/systems.conf contains
[my-cool-desktop]
kernelroot : /tmp/kernel_src_tree
[my-cool-server]
package : /var/tmp/my-packages
Then CONST.kernelroots[0] is '/tmp/kernel_src_tree' rather than the
default value '/var/tmp/grs/my-cool-desktop/kernel'. The remainder
of the constants default as delineated in the space[] dictionary with
%s replaced by 'my-cool-desktop'. Similarly CONST.my-cool-servers[1]
has package directory '/var/tmp/my-package' rather than the default
value '/var/tmp/grs/my-cool-server/packages',
Finally, the that class overrides __setattr__, __gettattr__ and
__delattr__ so that you cannot add/change/delete constants in
a GRS namespace.
"""
def __init__(self, configfile='/etc/grs/systems.conf'):
# If there's no config file, we're dead in the water.
if not os.path.isfile(configfile):
raise Exception('Configuration file %s not found\n' % configfile)
self.config = configparser.ConfigParser(delimiters=':', comment_prefixes='#')
self.config.read(configfile)
# These values will probably fail in the future, but that's okay
# because they really should never be used. They live outside of
# any GRS namespace and are just 'defaults'.
server = 'http://distfiles.gentoo.org/'
stagedir = 'releases/amd64/autobuilds/current-stage3-amd64-uclibc-hardened/'
stagefile = 'stage3-amd64-uclibc-hardened-20150510.tar.bz2'
default_stage_uri = server + stagedir + stagefile
# This is the space of all possible constants for any given GRS namespace
space = {
'repo_uri' : 'git://anongit.gentoo.org/proj/grs.git',
'stage_uri' : default_stage_uri,
'libdir' : '/var/lib/grs/%s',
'logfile' : '/var/log/grs/%s.log',
'tmpdir' : '/var/tmp/grs/%s',
'workdir' : '/var/tmp/grs/%s/work',
'package' : '/var/tmp/grs/%s/packages',
'kernelroot' : '/var/tmp/grs/%s/kernel',
'portage_configroot' : '/var/tmp/grs/%s/system',
'pidfile' : '/run/grs-%s.pid'
}
# We add an 's' to each list for a particular constant,
# and initialize the list to be empty.
for key in space:
self.__dict__[key+'s'] = []
# Each section is a 'namespace' corresponding to each GRS spec.
# We export these in the CONST.names[] list.
self.names = list(self.config.sections())
# We go over all the sections in the config file. The
# order here had better be the same as self.names[], else
# CONST.names[x] doesn't corresponde to the other CONST.foo[x]
# for every x.
for section in self.config.sections():
overrides = dict(self.config[section].items())
# Either we have an override value from the config
# file, else we contruct a default name.
for key in space:
if key in overrides:
value = overrides[key]
else:
# Either the default name has a slot %s to
# file or else it doesn't.
try:
value = space[key] % section
except TypeError:
value = space[key]
# We're counting on the order in which we append here to
# correspond to the GRS namespace for the key:value pair.
self.__dict__[key+'s'].append(value)
# Allow CONST.foo = bar only once!
def __setattr__(self, key, value):
if not key in self.__dict__:
self.__dict__[key] = value
else:
pass
# Don't retrieve the original else you can overwrite it,
# rather deep copy it.
def __getattr__(self, key, value=None):
if key in self.__dict__:
return deepcopy(self.__dict__[key])
# You can't del(CONST.foo).
def __delattr__(self, key):
if key in self.__dict__:
pass
# Instantiate once and export all our constant in CONST.
CONST = Constants()
# Constants outside any GRS namespace.
CONST.PACKAGE_NAME = "Gentoo Reference System"
CONST.PACKAGE_VERSION = 0.0
CONST.PACKAGE_DESCRIPTION = "Update a GRS by cloning a predefined system."
CONST.BUG_REPORTS = 'http://bugs.gentoo.org'
# The are defaults in case objects of other classes which depend on values
# of libdir, logfile, etc. are instantiated outside of any namespaces.
# They should not be needed under normal working condidtions.
CONST.LIBDIR = '/var/lib/grs'
CONST.LOGFILE = '/var/log/grs.log'
CONST.TMPDIR = '/var/tmp/grs'
CONST.WORKDIR = '/var/tmp/grs/work'
CONST.PACKAGE = '/var/tmp/grs/package'
CONST.KERNELROOT = '/var/tmp/grs/kernel'
CONST.PORTAGE_CONFIGROOT = '/var/tmp/grs/system'
CONST.PIDFILE = '/run/grs.pid'
# These are used by grsup and are hard coded values.
CONST.PORTAGE_CONFIGDIR = '/etc/portage'
CONST.PORTAGE_DIRTYFILE = '/etc/portage/.grs_dirty'
CONST.WORLD_CONFIG = '/etc/grs/world.conf'
CONST.GRS_CGROUP = 'grs'
CONST.GRS_CGROUPDIR = '/sys/fs/cgroup/grs'
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