scripts/common.py

# Copyright 2014 The Oppia Authors. 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.

"""Common utility functions and classes used by multiple Python scripts."""

import os


def ensure_directory_exists(d):
    """Creates the given directory if it does not already exist."""
    if not os.path.exists(d):
        os.makedirs(d)


def require_cwd_to_be_oppia():
    """Ensures that the current working directory ends in 'oppia'."""
    if not os.getcwd().endswith('oppia'):
        raise Exception('Please run this script from the oppia/ directory.')


class CD(object):
    """Context manager for changing the current working directory."""
    def __init__(self, new_path):
        self.new_path = new_path

    def __enter__(self):
        self.saved_path = os.getcwd()
        os.chdir(self.new_path)

    def __exit__(self, etype, value, traceback):
        os.chdir(self.saved_path)