python-glanceclient/glanceclient/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.

import errno
import os
import sys
import uuid

if os.name == 'nt':
    import msvcrt
else:
    msvcrt = None

import prettytable

from glanceclient import exc
from glanceclient.openstack.common import importutils
from glanceclient.openstack.common import strutils


# Decorator for cli-args
def arg(*args, **kwargs):
    def _decorator(func):
        # Because of the sematics of decorator composition if we just append
        # to the options list positional options will appear to be backwards.
        func.__dict__.setdefault('arguments', []).insert(0, (args, kwargs))
        return func
    return _decorator


def schema_args(schema_getter, omit=[]):
    typemap = {
        'string': str,
        'integer': int,
        'boolean': string_to_bool,
        'array': list
    }

    def _decorator(func):
        schema = schema_getter()
        if schema is None:
            param = '<unavailable>'
            kwargs = {
                'help': ("Please run with connection parameters set to "
                         "retrieve the schema for generating help for this "
                         "command")
            }
            func.__dict__.setdefault('arguments', []).insert(0, ((param, ),
                                                                 kwargs))
        else:
            properties = schema.get('properties', {})
            for name, property in properties.iteritems():
                if name in omit:
                    continue
                param = '--' + name.replace('_', '-')
                kwargs = {}

                type_str = property.get('type', 'string')
                if type_str == 'array':
                    items = property.get('items')
                    kwargs['type'] = typemap.get(items.get('type'))
                    kwargs['nargs'] = '+'
                else:
                    kwargs['type'] = typemap.get(type_str)

                if type_str == 'boolean':
                    kwargs['metavar'] = '[True|False]'
                else:
                    kwargs['metavar'] = '<%s>' % name.upper()

                description = property.get('description', "")
                if 'enum' in property:
                    if len(description):
                        description += " "
                    description += ("Valid values: " +
                                    ', '.join(property.get('enum')))
                kwargs['help'] = description

                func.__dict__.setdefault('arguments',
                                         []).insert(0, ((param, ), kwargs))
        return func

    return _decorator


def pretty_choice_list(l):
    return ', '.join("'%s'" % i for i in l)


def print_list(objs, fields, formatters={}):
    pt = prettytable.PrettyTable([f for f in fields], caching=False)
    pt.align = 'l'

    for o in objs:
        row = []
        for field in fields:
            if field in formatters:
                row.append(formatters[field](o))
            else:
                field_name = field.lower().replace(' ', '_')
                data = getattr(o, field_name, None) or ''
                row.append(data)
        pt.add_row(row)

    print strutils.safe_encode(pt.get_string())


def print_dict(d):
    pt = prettytable.PrettyTable(['Property', 'Value'], caching=False)
    pt.align = 'l'
    [pt.add_row(list(r)) for r in d.iteritems()]
    print strutils.safe_encode(pt.get_string(sortby='Property'))


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 exc.NotFound:
        pass

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

    # finally try to find entity by name
    matches = list(manager.list(filters={'name': name_or_id}))
    num_matches = len(matches)
    if num_matches == 0:
        msg = "No %s with a name or ID of '%s' exists." % \
              (manager.resource_class.__name__.lower(), name_or_id)
        raise exc.CommandError(msg)
    elif num_matches > 1:
        msg = ("Multiple %s matches found for '%s', use an ID to be more"
               " specific." % (manager.resource_class.__name__.lower(),
                               name_or_id))
        raise exc.CommandError(msg)
    else:
        return matches[0]


def skip_authentication(f):
    """Function decorator used to indicate a caller may be unauthenticated."""
    f.require_authentication = False
    return f


def is_authentication_required(f):
    """Checks to see if the function requires authentication.

    Use the skip_authentication decorator to indicate a caller may
    skip the authentication step.
    """
    return getattr(f, 'require_authentication', True)


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_versioned_module(version, submodule=None):
    module = 'glanceclient.v%s' % version
    if submodule:
        module = '.'.join((module, submodule))
    return importutils.import_module(module)


def exit(msg=''):
    if msg:
        print >> sys.stderr, strutils.safe_encode(msg)
    sys.exit(1)


def save_image(data, path):
    """
    Save an image to the specified path.

    :param data: binary data of the image
    :param path: path to save the image to
    """
    if path is None:
        image = sys.stdout
    else:
        image = open(path, 'wb')
    try:
        for chunk in data:
            image.write(chunk)
    finally:
        if path is not None:
            image.close()


def make_size_human_readable(size):
    suffix = ['B', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB']
    base = 1024.0

    index = 0
    while size >= base:
        index = index + 1
        size = size / base

    padded = '%.1f' % size
    stripped = padded.rstrip('0').rstrip('.')

    return '%s%s' % (stripped, suffix[index])


def getsockopt(self, *args, **kwargs):
    """
    A function which allows us to monkey patch eventlet's
    GreenSocket, adding a required 'getsockopt' method.
    TODO: (mclaren) we can remove this once the eventlet fix
    (https://bitbucket.org/eventlet/eventlet/commits/609f230)
    lands in mainstream packages.
    """
    return self.fd.getsockopt(*args, **kwargs)


def exception_to_str(exc):
    try:
        error = unicode(exc)
    except UnicodeError:
        try:
            error = str(exc)
        except UnicodeError:
            error = ("Caught '%(exception)s' exception." %
                     {"exception": exc.__class__.__name__})
    return strutils.safe_encode(error, errors='ignore')


def get_file_size(file_obj):
    """
    Analyze file-like object and attempt to determine its size.

    :param file_obj: file-like object.
    :retval The file's size or None if it cannot be determined.
    """
    if hasattr(file_obj, 'seek') and hasattr(file_obj, 'tell'):
        try:
            curr = file_obj.tell()
            file_obj.seek(0, os.SEEK_END)
            size = file_obj.tell()
            file_obj.seek(curr)
            return size
        except IOError as e:
            if e.errno == errno.ESPIPE:
                # Illegal seek. This means the file object
                # is a pipe (e.g the user is trying
                # to pipe image data to the client,
                # echo testdata | bin/glance add blah...), or
                # that file object is empty, or that a file-like
                # object which doesn't support 'seek/tell' has
                # been supplied.
                return
            else:
                raise


def get_data_file(args):
    if args.file:
        return open(args.file, 'rb')
    else:
        # distinguish cases where:
        # (1) stdin is not valid (as in cron jobs):
        #     glance ... <&-
        # (2) image data is provided through standard input:
        #     glance ... < /tmp/file or cat /tmp/file | glance ...
        # (3) no image data provided:
        #     glance ...
        try:
            os.fstat(0)
        except OSError:
            # (1) stdin is not valid (closed...)
            return None
        if not sys.stdin.isatty():
            # (2) image data is provided through standard input
            if msvcrt:
                msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
            return sys.stdin
        else:
            # (3) no image data provided
            return None