python-glanceclient/glanceclient/common/utils.py

# Copyright 2012 OpenStack Foundation
# 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.

from __future__ import print_function

import errno
import functools
import hashlib
import json
import os
import re
import six.moves.urllib.parse as urlparse
import sys
import threading
import uuid

from oslo_utils import importutils
import six

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

from oslo_utils import encodeutils
from oslo_utils import strutils
import prettytable

from glanceclient._i18n import _
from glanceclient import exc


_memoized_property_lock = threading.Lock()

SENSITIVE_HEADERS = ('X-Auth-Token', )
REQUIRED_FIELDS_ON_DATA = ('disk_format', 'container_format')


# 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 on_data_require_fields(data_fields, required=REQUIRED_FIELDS_ON_DATA):
    """Decorator to check commands' validity

    This decorator checks that required fields are present when image
    data has been supplied via command line arguments or via stdin

    On error throws CommandError exception with meaningful message.

    :param data_fields: Which fields' presence imply image data
    :type data_fields: iter
    :param required: Required fields
    :type required: iter
    :return: function decorator
    """

    def args_decorator(func):
        def prepare_fields(fields):
            args = ('--' + x.replace('_', '-') for x in fields)
            return ', '.join(args)

        @functools.wraps(func)
        def func_wrapper(gc, args):
            # Set of arguments with data
            fields = set(a[0] for a in vars(args).items() if a[1])

            # Fields the conditional requirements depend on
            present = fields.intersection(data_fields)

            # How many conditional requirements are missing
            missing = set(required) - fields

            # We use get_data_file to check if data is provided in stdin
            if (present or get_data_file(args)) and missing:
                msg = (_("error: Must provide %(req)s when using %(opt)s.") %
                       {'req': prepare_fields(missing),
                        'opt': prepare_fields(present) or 'stdin'})
                raise exc.CommandError(msg)
            return func(gc, args)
        return func_wrapper
    return args_decorator


def schema_args(schema_getter, omit=None):
    omit = omit or []
    typemap = {
        'string': encodeutils.safe_decode,
        'integer': int,
        'boolean': strutils.bool_from_string,
        '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 six.iteritems(properties):
                if name in omit:
                    continue
                param = '--' + name.replace('_', '-')
                kwargs = {}

                type_str = property.get('type', 'string')

                if isinstance(type_str, list):
                    # NOTE(flaper87): This means the server has
                    # returned something like `['null', 'string']`,
                    # therfore we use the first non-`null` type as
                    # the valid type.
                    for t in type_str:
                        if t != 'null':
                            type_str = t
                            break

                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 += " "

                    # NOTE(flaper87): Make sure all values are `str/unicode`
                    # for the `join` to succeed. Enum types can also be `None`
                    # therfore, join's call would fail without the following
                    # list comprehension
                    vals = [six.text_type(val) for val in property.get('enum')]
                    description += ('Valid values: ' + ', '.join(vals))
                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=None, field_settings=None):
    formatters = formatters or {}
    field_settings = field_settings or {}
    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 field_settings:
                for setting, value in six.iteritems(field_settings[field]):
                    setting_dict = getattr(pt, setting)
                    setting_dict[field] = value

            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(encodeutils.safe_decode(pt.get_string()))


def print_dict(d, max_column_width=80):
    pt = prettytable.PrettyTable(['Property', 'Value'], caching=False)
    pt.align = 'l'
    pt.max_width = max_column_width
    for k, v in six.iteritems(d):
        if isinstance(v, (dict, list)):
            v = json.dumps(v)
        pt.add_row([k, v])
    print(encodeutils.safe_decode(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:
        # This must be unicode for Python 3 compatibility.
        # If you pass a bytestring to uuid.UUID, you will get a TypeError
        uuid.UUID(encodeutils.safe_decode(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 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='', exit_code=1):
    if msg:
        print_err(msg)
    sys.exit(exit_code)


def print_err(msg):
    print(encodeutils.safe_decode(msg), file=sys.stderr)


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:
        if six.PY3:
            image = sys.stdout.buffer
        else:
            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

    if size is None:
        size = 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 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') and
            (six.PY2 or six.PY3 and file_obj.seekable())):
        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


def strip_version(endpoint):
    """Strip version from the last component of endpoint if present."""
    # NOTE(flaper87): This shouldn't be necessary if
    # we make endpoint the first argument. However, we
    # can't do that just yet because we need to keep
    # backwards compatibility.
    if not isinstance(endpoint, six.string_types):
        raise ValueError("Expected endpoint")

    version = None
    # Get rid of trailing '/' if present
    endpoint = endpoint.rstrip('/')
    url_parts = urlparse.urlparse(endpoint)
    (scheme, netloc, path, __, __, __) = url_parts
    path = path.lstrip('/')
    # regex to match 'v1' or 'v2.0' etc
    if re.match('v\d+\.?\d*', path):
        version = float(path.lstrip('v'))
        endpoint = scheme + '://' + netloc
    return endpoint, version


def print_image(image_obj, human_readable=False, max_col_width=None):
    ignore = ['self', 'access', 'file', 'schema']
    image = dict([item for item in six.iteritems(image_obj)
                  if item[0] not in ignore])
    if human_readable:
        image['size'] = make_size_human_readable(image['size'])
    if str(max_col_width).isdigit():
        print_dict(image, max_column_width=max_col_width)
    else:
        print_dict(image)


def integrity_iter(iter, checksum):
    """Check image data integrity.

    :raises: IOError
    """
    md5sum = hashlib.md5()
    for chunk in iter:
        yield chunk
        if isinstance(chunk, six.string_types):
            chunk = six.b(chunk)
        md5sum.update(chunk)
    md5sum = md5sum.hexdigest()
    if md5sum != checksum:
        raise IOError(errno.EPIPE,
                      'Corrupt image download. Checksum was %s expected %s' %
                      (md5sum, checksum))


def memoized_property(fn):
    attr_name = '_lazy_once_' + fn.__name__

    @property
    def _memoized_property(self):
        if hasattr(self, attr_name):
            return getattr(self, attr_name)
        else:
            with _memoized_property_lock:
                if not hasattr(self, attr_name):
                    setattr(self, attr_name, fn(self))
            return getattr(self, attr_name)
    return _memoized_property


def safe_header(name, value):
    if value is not None and name in SENSITIVE_HEADERS:
        h = hashlib.sha1(value)
        d = h.hexdigest()
        return name, "{SHA1}%s" % d
    else:
        return name, value


def endpoint_version_from_url(endpoint, default_version=None):
    if endpoint:
        endpoint, version = strip_version(endpoint)
        return endpoint, version or default_version
    else:
        return None, default_version


class IterableWithLength(object):
    def __init__(self, iterable, length):
        self.iterable = iterable
        self.length = length

    def __iter__(self):
        try:
            for chunk in self.iterable:
                yield chunk
        finally:
            self.iterable.close()

    def next(self):
        return next(self.iterable)

    def __len__(self):
        return self.length