# substitutions.py

# Config file substitutions.

#

# Copyright (C) 2012-2016 Red Hat, Inc.

#

# This copyrighted material is made available to anyone wishing to use,

# modify, copy, or redistribute it subject to the terms and conditions of

# the GNU General Public License v.2, or (at your option) any later version.

# This program is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY expressed or implied, including the implied warranties 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, write to the

# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.  Any Red Hat trademarks that are incorporated in the

# source code or documentation are not subject to the GNU General Public

# License and may only be used or replicated with the express permission of

# Red Hat, Inc.

#

import os

import re

import dnf

import dnf.exceptions

ENVIRONMENT_VARS_RE = re.compile(r'^DNF_VAR_[A-Za-z0-9_]+$')

class Substitutions(dict):

    # :api

    def __init__(self):

        super(Substitutions, self).__init__()

        self._update_from_env()

    def _update_from_env(self):

        numericvars = ['DNF%d' % num for num in range(0, 10)]

        for key, val in os.environ.items():

            if ENVIRONMENT_VARS_RE.match(key):

                self[key[8:]] = val  # remove "DNF_VAR_" prefix

            elif key in numericvars:

                self[key] = val

    def update_from_etc(self, installroot, varsdir=("/etc/yum/vars/", "/etc/dnf/vars/")):

        # :api

        for vars_path in varsdir:

            fsvars = []

            try:

                dir_fsvars = os.path.join(installroot, vars_path.lstrip('/'))

                fsvars = os.listdir(dir_fsvars)

            except OSError:

                continue

            for fsvar in fsvars:

                filepath = os.path.join(dir_fsvars, fsvar)

                if os.path.isfile(filepath):

                    try:

                        with open(filepath) as fp:

                            val = fp.readline()

                        if val and val[-1] == '\n':

                            val = val[:-1]

                    except (OSError, IOError):

                        continue

                self[fsvar] = val