Mini Shell

# -*- coding: utf-8 -*-

from __future__ import print_function, division, absolute_import
#
# Copyright (c) 2018 Red Hat, Inc.
#
# This software is licensed to you under the GNU General Public License,
# version 2 (GPLv2). There is NO WARRANTY for this software, express or
# implied, including the implied warranties of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. You should have received a copy of GPLv2
# along with this software; if not, see
# http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
#
# Red Hat trademarks are not licensed under GPLv2. No permission is
# granted to use or replicate Red Hat trademarks that are incorporated
# in this software or its documentation.

"""
Utility methods for the syspurpose command
"""

import io
import json
import os
import errno
import sys
import six
from syspurpose.i18n import ugettext as _

HOST_CONFIG_DIR = "/etc/rhsm-host/"  # symlink inside docker containers


# Borrowed from the subscription-manager cli script
def system_exit(code, msgs=None):
    """Exit with a code and optional message(s). Saved a few lines of code."""

    if msgs:
        if type(msgs) not in [type([]), type(())]:
            msgs = (msgs, )
        for msg in msgs:
            sys.stderr.write(str(msg) + '\n')
    sys.exit(code)


def create_dir(path):
    """
    Attempts to create the path given (less any file)
    :param path: path
    :return: True if changes were made, false otherwise
    """
    try:
        os.makedirs(path, mode=0o755)
    except OSError as e:
        if e.errno == errno.EEXIST:
            # If the directory exists no changes necessary
            return False
        if e.errno == errno.EACCES:
            system_exit(os.EX_NOPERM,
                        _('Cannot create directory {}\nAre you root?').format(path))
    return True


def create_file(path, contents):
    """
    Attempts to create a file, with the given contents
    :param path: The desired path to the file
    :param contents: The contents to write to the file, should json-serializable
    :return: True if the file was newly created, false otherwise
    """
    try:
        with io.open(path, 'w', encoding='utf-8') as f:
            write_to_file_utf8(f, contents)
            f.flush()

    except OSError as e:
        if e.errno == errno.EEXIST:
            # If the file exists no changes necessary
            return False
        if e.errno == errno.EACCES:
            system_exit(os.EX_NOPERM, _("Cannot create file {}\nAre you root?").format(path))
        else:
            raise
    return True


# Borrowed from the subscription-manager config module
def in_container():
    """
    Are we running in a docker container or not?

    Assumes that if we see host rhsm configuration shared with us, we must
    be running in a container.
    """
    if os.path.exists(HOST_CONFIG_DIR):
        return True
    return False


def make_utf8(obj):
    """
    Transforms the provided string into unicode if it is not already
    :param obj: the string to decode
    :return: the unicode format of the string
    """
    if six.PY3:
        return obj
    elif obj is not None and isinstance(obj, str) and not isinstance(obj, unicode):
        obj =  obj.decode('utf-8')
        return obj
    else:
        return obj


def write_to_file_utf8(file, data):
    """
    Writes out the provided data to the specified file, with user-friendly indentation,
    and in utf-8 encoding.
    :param file: The file to write to
    :param data: The data to be written
    :return:
    """
    file.write(make_utf8(json.dumps(data, indent=2, ensure_ascii=False, sort_keys=True)))