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  • Committer: Colin Watson
  • Date: 2012-08-03 15:38:59 UTC
  • mto: This revision was merged to the branch mainline in revision 929.
  • Revision ID: cjwatson@canonical.com-20120803153859-jixq70nf2fgcs221
Add Python config module to read shell-based cdimage configuration.

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lib/cdimage/config.py
 
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# Copyright (C) 2012 Canonical Ltd.
 
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# Author: Colin Watson <cjwatson@ubuntu.com>
 
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# This program is free software: you can redistribute it and/or modify
 
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# it under the terms of the GNU General Public License as published by
 
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# the Free Software Foundation; version 3 of the License.
 
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#
 
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# This program is distributed in the hope that it will be useful,
 
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
 
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 
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# GNU General Public License for more details.
 
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#
 
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# You should have received a copy of the GNU General Public License
 
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# along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
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"""Read cdimage configuration.
 
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This is a transitional measure to permit shell and Python programs to
 
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co-exist until such time as the whole of cdimage is rewritten.
 
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"""
 
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__metaclass__ = type
 
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from collections import defaultdict
 
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import os
 
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import re
 
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import subprocess
 
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_whitelisted_keys = (
 
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    "PROJECT",
 
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    "CAPPROJECT",
 
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    "ALL_DISTS",
 
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    "DIST",
 
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    "ALL_PROJECTS",
 
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    "ARCHES",
 
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    "CPUARCHES",
 
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    "GNUPG_DIR",
 
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    "SIGNING_KEYID",
 
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    "BRITNEY",
 
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    "LOCAL_SEEDS",
 
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    "TRIGGER_MIRRORS",
 
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    "TRIGGER_MIRRORS_ASYNC",
 
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    "DEBOOTSTRAPROOT",
 
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    )
 
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class Config(defaultdict):
 
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    def __init__(self):
 
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        super(Config, self).__init__(str)
 
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        if "CDIMAGE_ROOT" not in os.environ:
 
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            os.environ["CDIMAGE_ROOT"] = "/srv/cdimage.ubuntu.com"
 
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        self.root = os.environ["CDIMAGE_ROOT"]
 
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        self._read()
 
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    def _read_nullsep_output(self, command):
 
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        raw = subprocess.Popen(
 
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            command, stdout=subprocess.PIPE,
 
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            universal_newlines=True).communicate()[0]
 
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        out = {}
 
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        for line in raw.split("\0"):
 
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            try:
 
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                key, value = line.split("=", 1)
 
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                out[key] = value
 
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            except ValueError:
 
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                continue
 
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        return out
 
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    def _shell_escape(self, arg):
 
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        if re.match(r"^[a-zA-Z0-9+,./:=@_-]+$", arg):
 
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            return arg
 
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        else:
 
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            return "'%s'" % arg.replace("'", "'\\''")
 
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    def _read(self):
 
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        config_path = os.path.join(self.root, "etc", "config")
 
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        commands = [". %s" % self._shell_escape(config_path)]
 
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        for key in _whitelisted_keys:
 
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            commands.append("printf '%%s\\0' \"%s=$%s\"" % (key, key))
 
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        env = self._read_nullsep_output(["sh", "-c", "; ".join(commands)])
 
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        self.update(env)