python-openstackclient/openstackclient/common/utils.py

# Copyright 2012 OpenStack LLC.
# 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.
#
# vim: tabstop=4 shiftwidth=4 softtabstop=4

"""
Common client utilities
"""

import os
import sys
import uuid

import prettytable

from openstackclient.common import exceptions


def find_resource(manager, name_or_id):
    """Helper for the _find_* methods."""
    # first try to get entity as integer id
    try:
        if isinstance(name_or_id, int) or name_or_id.isdigit():
            return manager.get(int(name_or_id))
    except exceptions.NotFound:
        pass

    # now try to get entity as uuid
    try:
        uuid.UUID(str(name_or_id))
        return manager.get(name_or_id)
    except (ValueError, exceptions.NotFound):
        pass

    # finally try to find entity by name
    try:
        return manager.find(name=name_or_id)
    except exceptions.NotFound:
        msg = "No %s with a name or ID of '%s' exists." % \
              (manager.resource_class.__name__.lower(), name_or_id)
        raise exceptions.CommandError(msg)


def get_item_properties(item, fields, mixed_case_fields=[], formatters={}):
    """Return a tuple containing the item properties.

    :param item: a single item resource (e.g. Server, Tenant, etc)
    :param fields: tuple of strings with the desired field names
    :param mixed_case_fields: tuple of field names to preserve case
    :param formatters: dictionary mapping field names to callables
       to format the values
    """
    row = []

    for field in fields:
        if field in formatters:
            row.append(formatters[field](item))
        else:
            if field in mixed_case_fields:
                field_name = field.replace(' ', '_')
            else:
                field_name = field.lower().replace(' ', '_')
            data = getattr(item, field_name, '')
            row.append(data)
    return tuple(row)


def string_to_bool(arg):
    return arg.strip().lower() in ('t', 'true', 'yes', '1')


def env(*vars, **kwargs):
    """Search for the first defined of possibly many env vars

    Returns the first environment variable defined in vars, or
    returns the default defined in kwargs.
    """
    for v in vars:
        value = os.environ.get(v, None)
        if value:
            return value
    return kwargs.get('default', '')


def import_class(import_str):
    """Returns a class from a string including module and class."""
    mod_str, _sep, class_str = import_str.rpartition('.')
    __import__(mod_str)
    return getattr(sys.modules[mod_str], class_str)