python-cinderclient/cinderclient/client.py

858 lines
32 KiB
Python

# Copyright (c) 2011 OpenStack Foundation
# Copyright 2010 Jacob Kaplan-Moss
# Copyright 2011 Piston Cloud Computing, Inc.
# 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.
"""OpenStack Client interface. Handles the REST calls and responses."""
import glob
import hashlib
import importlib.util
import itertools
import logging
import os
import pkgutil
import re
import urllib
from urllib import parse as urlparse
from keystoneauth1 import access
from keystoneauth1 import adapter
from keystoneauth1 import discover
from keystoneauth1.identity import base
from oslo_utils import encodeutils
from oslo_utils import importutils
from oslo_utils import strutils
import requests
from cinderclient._i18n import _
from cinderclient import api_versions
from cinderclient import exceptions
import cinderclient.extension
try:
from eventlet import sleep
except ImportError:
from time import sleep
try:
import json
except ImportError:
import simplejson as json
try:
osprofiler_web = importutils.try_import("osprofiler.web")
except Exception:
pass
_VALID_VERSIONS = ['v2', 'v3']
V3_SERVICE_TYPE = 'volumev3'
V2_SERVICE_TYPE = 'volumev2'
SERVICE_TYPES = {'2': V2_SERVICE_TYPE,
'3': V3_SERVICE_TYPE}
REQ_ID_HEADER = 'X-OpenStack-Request-ID'
# tell keystoneclient that we can ignore the /v1|v2/{project_id} component of
# the service catalog when doing discovery lookups
for svc in ('volume', 'volumev2', 'volumev3'):
discover.add_catalog_discover_hack(svc, re.compile(r'/v[12]/\w+/?$'), '/')
def get_server_version(url, insecure=False, cacert=None, cert=None):
"""Queries the server via the naked endpoint and gets version info.
:param url: url of the cinder endpoint
:param insecure: Explicitly allow client to perform "insecure" TLS
(https) requests
:param cacert: Specify a CA bundle file to use in verifying a TLS
(https) server certificate
:param cert: A client certificate to pass to requests. These are of the
same form as requests expects. Either a single filename
containing both the certificate and key or a tuple containing
the path to the certificate then a path to the key. (optional)
:returns: APIVersion object for min and max version supported by
the server
"""
min_version = "2.0"
current_version = "2.0"
logger = logging.getLogger(__name__)
try:
u = urllib.parse.urlparse(url)
version_url = None
# NOTE(andreykurilin): endpoint URL has at least 2 formats:
# 1. The classic (legacy) endpoint:
# http://{host}:{optional_port}/v{2 or 3}/{project-id}
# http://{host}:{optional_port}/v{2 or 3}
# 3. Under wsgi:
# http://{host}:{optional_port}/volume/v{2 or 3}
for ver in ['v2', 'v3']:
if u.path.endswith(ver) or "/{0}/".format(ver) in u.path:
path = u.path[:u.path.rfind(ver)]
version_url = '%s://%s%s' % (u.scheme, u.netloc, path)
break
if not version_url:
# NOTE(andreykurilin): probably, it is one of the next cases:
# * https://volume.example.com/
# * https://example.com/volume
# leave as is without cropping.
version_url = url
if insecure:
verify_cert = False
else:
if cacert:
verify_cert = cacert
else:
verify_cert = True
response = requests.get(version_url, verify=verify_cert, cert=cert)
data = json.loads(response.text)
versions = data['versions']
for version in versions:
if '3.' in version['version']:
min_version = version['min_version']
current_version = version['version']
break
else:
# Set the values, but don't break out the loop here in case v3
# comes later
min_version = '2.0'
current_version = '2.0'
except exceptions.ClientException as e:
logger.warning("Error in server version query:%s\n"
"Returning APIVersion 2.0", str(e.message))
return (api_versions.APIVersion(min_version),
api_versions.APIVersion(current_version))
def get_highest_client_server_version(url, insecure=False,
cacert=None, cert=None):
"""Returns highest supported version by client and server as a string."""
min_server, max_server = get_server_version(url, insecure, cacert, cert)
max_client = api_versions.APIVersion(api_versions.MAX_VERSION)
return min(max_server, max_client).get_string()
def get_volume_api_from_url(url):
scheme, netloc, path, query, frag = urlparse.urlsplit(url)
components = path.split("/")
for version in _VALID_VERSIONS:
if version in components:
return version[1:]
msg = (_("Invalid url: '%(url)s'. It must include one of: %(version)s.")
% {'url': url, 'version': ', '.join(_VALID_VERSIONS)})
raise exceptions.UnsupportedVersion(msg)
def _log_request_id(logger, resp, service_name):
request_id = resp.headers.get('x-openstack-request-id')
if request_id:
logger.debug('%(method)s call to %(service_type)s for %(url)s '
'used request id %(response_request_id)s',
{'method': resp.request.method,
'service_type': service_name,
'url': resp.url, 'response_request_id': request_id})
class SessionClient(adapter.LegacyJsonAdapter):
def __init__(self, *args, **kwargs):
apiver = kwargs.pop('api_version', None) or api_versions.APIVersion()
if not isinstance(apiver, api_versions.APIVersion):
apiver = api_versions.APIVersion(str(apiver))
if apiver.ver_minor != 0:
kwargs['default_microversion'] = apiver.get_string()
self.retries = kwargs.pop('retries', 0)
self._logger = logging.getLogger(__name__)
super(SessionClient, self).__init__(*args, **kwargs)
def request(self, *args, **kwargs):
kwargs.setdefault('authenticated', False)
# Note(tpatil): The standard call raises errors from
# keystoneauth, here we need to raise the cinderclient errors.
raise_exc = kwargs.pop('raise_exc', True)
resp, body = super(SessionClient, self).request(*args,
raise_exc=False,
**kwargs)
if raise_exc and resp.status_code >= 400:
raise exceptions.from_response(resp, body)
if not self.global_request_id:
self.global_request_id = resp.headers.get('x-openstack-request-id')
return resp, body
def _cs_request(self, url, method, **kwargs):
# this function is mostly redundant but makes compatibility easier
kwargs.setdefault('authenticated', True)
attempts = 0
while True:
attempts += 1
try:
return self.request(url, method, **kwargs)
except exceptions.OverLimit as overlim:
if attempts > self.retries or overlim.retry_after < 1:
raise
msg = "Retrying after %s seconds." % overlim.retry_after
self._logger.debug(msg)
sleep(overlim.retry_after)
def get(self, url, **kwargs):
return self._cs_request(url, 'GET', **kwargs)
def post(self, url, **kwargs):
return self._cs_request(url, 'POST', **kwargs)
def put(self, url, **kwargs):
return self._cs_request(url, 'PUT', **kwargs)
def delete(self, url, **kwargs):
return self._cs_request(url, 'DELETE', **kwargs)
def _get_base_url(self):
endpoint = self.get_endpoint()
m = re.search('(.+)/v[1-3].*', endpoint)
if m:
# Get everything up until the version identifier
base_url = '%s/' % m.group(1)
else:
# Fall back to the root of the URL
base_url = '/'.join(endpoint.split('/')[:3]) + '/'
return base_url
def get_volume_api_version_from_endpoint(self):
try:
version = get_volume_api_from_url(self.get_endpoint())
except exceptions.UnsupportedVersion as e:
msg = (_("Service catalog returned invalid url.\n"
"%s") % str(e))
raise exceptions.UnsupportedVersion(msg)
return version
def authenticate(self, auth=None):
self.invalidate(auth)
return self.get_token(auth)
@property
def service_catalog(self):
# NOTE(jamielennox): This is ugly and should be deprecated.
auth = self.auth or self.session.auth
if isinstance(auth, base.BaseIdentityPlugin):
return auth.get_access(self.session).service_catalog
raise AttributeError('There is no service catalog for this type of '
'auth plugin.')
def _cs_request_base_url(self, url, method, **kwargs):
base_url = self._get_base_url()
return self._cs_request(
base_url + url,
method,
**kwargs)
def get_with_base_url(self, url, **kwargs):
return self._cs_request_base_url(url, 'GET', **kwargs)
def create_update_with_base_url(self, url, **kwargs):
return self._cs_request_base_url(url, 'PUT', **kwargs)
def delete_with_base_url(self, url, **kwargs):
return self._cs_request_base_url(url, 'DELETE', **kwargs)
class HTTPClient(object):
SENSITIVE_HEADERS = ('X-Auth-Token', 'X-Subject-Token',)
USER_AGENT = 'python-cinderclient'
def __init__(self, user, password, projectid, auth_url=None,
insecure=False, timeout=None, tenant_id=None,
proxy_tenant_id=None, proxy_token=None, region_name=None,
endpoint_type='publicURL', service_type=None,
service_name=None, volume_service_name=None,
os_endpoint=None, retries=None,
http_log_debug=False, cacert=None, cert=None,
auth_system='keystone', auth_plugin=None, api_version=None,
logger=None, user_domain_name='Default',
project_domain_name='Default', global_request_id=None):
self.user = user
self.password = password
self.projectid = projectid
self.tenant_id = tenant_id
self.api_version = api_version or api_versions.APIVersion()
self.global_request_id = global_request_id
if auth_system and auth_system != 'keystone' and not auth_plugin:
raise exceptions.AuthSystemNotFound(auth_system)
if not auth_url and auth_system and auth_system != 'keystone':
auth_url = auth_plugin.get_auth_url()
if not auth_url:
raise exceptions.EndpointNotFound()
self.auth_url = auth_url.rstrip('/') if auth_url else None
self.ks_version = 'v1'
self.region_name = region_name
self.endpoint_type = endpoint_type
self.service_type = service_type
self.service_name = service_name
self.volume_service_name = volume_service_name
self.os_endpoint = os_endpoint.rstrip('/') \
if os_endpoint else os_endpoint
self.retries = int(retries or 0)
self.http_log_debug = http_log_debug
self.management_url = self.os_endpoint or None
self.auth_token = None
self.proxy_token = proxy_token
self.proxy_tenant_id = proxy_tenant_id
self.timeout = timeout
self.user_domain_name = user_domain_name
self.project_domain_name = project_domain_name
self.cert = cert
if insecure:
self.verify_cert = False
else:
if cacert:
self.verify_cert = cacert
else:
self.verify_cert = True
self.auth_system = auth_system
self.auth_plugin = auth_plugin
self._logger = logger or logging.getLogger(__name__)
def _safe_header(self, name, value):
if name in HTTPClient.SENSITIVE_HEADERS:
encoded = value.encode('utf-8')
hashed = hashlib.sha1(encoded)
digested = hashed.hexdigest()
return encodeutils.safe_decode(name), "{SHA1}%s" % digested
else:
return (encodeutils.safe_decode(name),
encodeutils.safe_decode(value))
def http_log_req(self, args, kwargs):
if not self.http_log_debug:
return
string_parts = ['curl -i']
for element in args:
if element in ('GET', 'POST', 'DELETE', 'PUT'):
string_parts.append(' -X %s' % element)
else:
string_parts.append(' %s' % element)
for element in kwargs['headers']:
header = ("-H '%s: %s'" %
self._safe_header(element, kwargs['headers'][element]))
string_parts.append(header)
if 'data' in kwargs:
data = strutils.mask_password(kwargs['data'])
string_parts.append(" -d '%s'" % (data))
self._logger.debug("\nREQ: %s\n" % "".join(string_parts))
def http_log_resp(self, resp):
if not self.http_log_debug:
return
self._logger.debug(
"RESP: [%s] %s\nRESP BODY: %s\n",
resp.status_code,
resp.headers,
strutils.mask_password(resp.text))
# if service name is None then use service_type for logging
service = self.service_name or self.service_type
_log_request_id(self._logger, resp, service)
def request(self, url, method, **kwargs):
kwargs.setdefault('headers', kwargs.get('headers', {}))
kwargs['headers']['User-Agent'] = self.USER_AGENT
kwargs['headers']['Accept'] = 'application/json'
if osprofiler_web:
kwargs['headers'].update(osprofiler_web.get_trace_id_headers())
if 'body' in kwargs:
kwargs['headers']['Content-Type'] = 'application/json'
kwargs['data'] = json.dumps(kwargs.pop('body'))
api_versions.update_headers(kwargs["headers"], self.api_version)
if self.global_request_id:
kwargs['headers'].setdefault(REQ_ID_HEADER, self.global_request_id)
if self.timeout:
kwargs.setdefault('timeout', self.timeout)
self.http_log_req((url, method,), kwargs)
resp = requests.request(
method,
url,
verify=self.verify_cert,
cert=self.cert,
**kwargs)
self.http_log_resp(resp)
body = None
if resp.text:
try:
body = json.loads(resp.text)
except ValueError as e:
self._logger.debug("Load http response text error: %s", e)
if resp.status_code >= 400:
raise exceptions.from_response(resp, body)
return resp, body
def _cs_request(self, url, method, **kwargs):
auth_attempts = 0
attempts = 0
backoff = 1
while True:
attempts += 1
if not self.management_url or not self.auth_token:
self.authenticate()
kwargs.setdefault('headers', {})['X-Auth-Token'] = self.auth_token
if self.projectid:
kwargs['headers']['X-Auth-Project-Id'] = self.projectid
try:
if not url.startswith(self.management_url):
url = self.management_url + url
resp, body = self.request(url, method, **kwargs)
return resp, body
except exceptions.BadRequest:
if attempts > self.retries:
raise
except exceptions.Unauthorized:
if auth_attempts > 0:
raise
self._logger.debug("Unauthorized, reauthenticating.")
self.management_url = self.auth_token = None
# First reauth. Discount this attempt.
attempts -= 1
auth_attempts += 1
continue
except exceptions.OverLimit as overlim:
if attempts > self.retries or overlim.retry_after < 1:
raise
msg = "Retrying after %s seconds." % overlim.retry_after
self._logger.debug(msg)
sleep(overlim.retry_after)
continue
except exceptions.ClientException as e:
if attempts > self.retries:
raise
if 500 <= e.code <= 599:
pass
else:
raise
except requests.exceptions.ConnectionError as e:
self._logger.debug("Connection error: %s" % e)
if attempts > self.retries:
msg = 'Unable to establish connection: %s' % e
raise exceptions.ConnectionError(msg)
except requests.exceptions.Timeout as e:
self._logger.debug("Timeout error: %s" % e)
if attempts > self.retries:
raise
self._logger.debug(
"Failed attempt(%s of %s), retrying in %s seconds" %
(attempts, self.retries, backoff))
sleep(backoff)
backoff *= 2
def get(self, url, **kwargs):
return self._cs_request(url, 'GET', **kwargs)
def post(self, url, **kwargs):
return self._cs_request(url, 'POST', **kwargs)
def put(self, url, **kwargs):
return self._cs_request(url, 'PUT', **kwargs)
def delete(self, url, **kwargs):
return self._cs_request(url, 'DELETE', **kwargs)
def get_volume_api_version_from_endpoint(self):
try:
version = get_volume_api_from_url(self.management_url)
except exceptions.UnsupportedVersion as e:
if self.management_url == self.os_endpoint:
msg = (_("Invalid url was specified in --os-endpoint %s")
% str(e))
else:
msg = (_("Service catalog returned invalid url.\n"
"%s") % str(e))
raise exceptions.UnsupportedVersion(msg)
return version
def _extract_service_catalog(self, url, resp, body, extract_token=True):
"""See what the auth service told us and process the response.
We may get redirected to another site, fail or actually get
back a service catalog with a token and our endpoints.
"""
# content must always present
if resp.status_code == 200 or resp.status_code == 201:
try:
self.auth_url = url
self.auth_ref = access.create(resp=resp, body=body)
self.service_catalog = self.auth_ref.service_catalog
if extract_token:
self.auth_token = self.auth_ref.auth_token
management_url = self.service_catalog.url_for(
region_name=self.region_name,
interface=self.endpoint_type,
service_type=self.service_type,
service_name=self.service_name)
self.management_url = management_url.rstrip('/')
return None
except exceptions.AmbiguousEndpoints:
print("Found more than one valid endpoint. Use a more "
"restrictive filter")
raise
except ValueError:
# ValueError is raised when you pass an invalid response to
# access.create. This should never happen in reality if the
# status code is 200.
raise exceptions.AuthorizationFailure()
except exceptions.EndpointNotFound:
print("Could not find any suitable endpoint. Correct region?")
raise
elif resp.status_code == 305:
return resp.headers['location']
else:
raise exceptions.from_response(resp, body)
def _fetch_endpoints_from_auth(self, url):
"""We have a token, but don't know the final endpoint for
the region. We have to go back to the auth service and
ask again. This request requires an admin-level token
to work. The proxy token supplied could be from a low-level enduser.
We can't get this from the keystone service endpoint, we have to use
the admin endpoint.
This will overwrite our admin token with the user token.
"""
# GET ...:5001/v2.0/tokens/#####/endpoints
url = '/'.join([url, 'tokens', '%s?belongsTo=%s'
% (self.proxy_token, self.proxy_tenant_id)])
self._logger.debug("Using Endpoint URL: %s" % url)
resp, body = self.request(url, "GET",
headers={'X-Auth-Token': self.auth_token})
return self._extract_service_catalog(url, resp, body,
extract_token=False)
def set_management_url(self, url):
self.management_url = url
def authenticate(self):
magic_tuple = urlparse.urlsplit(self.auth_url)
scheme, netloc, path, query, frag = magic_tuple
port = magic_tuple.port
if port is None:
port = 80
path_parts = path.split('/')
for part in path_parts:
if len(part) > 0 and part[0] == 'v':
self.ks_version = part
break
# TODO(sandy): Assume admin endpoint is 35357 for now.
# Ideally this is going to have to be provided by the service catalog.
new_netloc = netloc.replace(':%d' % port, ':%d' % (35357,))
admin_url = urlparse.urlunsplit((scheme, new_netloc,
path, query, frag))
auth_url = self.auth_url
if 'v2' in self.ks_version or 'v3' in self.ks_version:
while auth_url:
if not self.auth_system or self.auth_system == 'keystone':
auth_url = self._v2_or_v3_auth(auth_url)
# Are we acting on behalf of another user via an
# existing token? If so, our actual endpoints may
# be different than that of the admin token.
if self.proxy_token:
if self.os_endpoint:
self.set_management_url(self.os_endpoint)
else:
self._fetch_endpoints_from_auth(admin_url)
# Since keystone no longer returns the user token
# with the endpoints any more, we need to replace
# our service account token with the user token.
self.auth_token = self.proxy_token
else:
try:
while auth_url:
auth_url = self._v1_auth(auth_url)
# In some configurations cinder makes redirection to
# v2.0 keystone endpoint. Also, new location does not contain
# real endpoint, only hostname and port.
except exceptions.AuthorizationFailure:
if auth_url.find('v2.0') < 0:
auth_url = auth_url + '/v2.0'
self._v2_or_v3_auth(auth_url)
if self.os_endpoint:
self.set_management_url(self.os_endpoint)
elif not self.management_url:
raise exceptions.Unauthorized('Cinder Client')
def _v1_auth(self, url):
if self.proxy_token:
raise exceptions.NoTokenLookupException()
headers = {'X-Auth-User': self.user,
'X-Auth-Key': self.password}
if self.projectid:
headers['X-Auth-Project-Id'] = self.projectid
resp, body = self.request(url, 'GET', headers=headers)
if resp.status_code in (200, 204): # in some cases we get No Content
try:
mgmt_header = 'x-server-management-url'
self.management_url = resp.headers[mgmt_header].rstrip('/')
self.auth_token = resp.headers['x-auth-token']
self.auth_url = url
except (KeyError, TypeError):
raise exceptions.AuthorizationFailure()
elif resp.status_code == 305:
return resp.headers['location']
else:
raise exceptions.from_response(resp, body)
def _v2_or_v3_auth(self, url):
"""Authenticate against a v2.0 auth service."""
if self.ks_version == "v3":
body = {
"auth": {
"identity": {
"methods": ["password"],
"password": {"user": {
"domain": {"name": self.user_domain_name},
"name": self.user,
"password": self.password}}},
}
}
scope = {"project": {"domain": {"name": self.project_domain_name}}}
if self.projectid:
scope['project']['name'] = self.projectid
elif self.tenant_id:
scope['project']['id'] = self.tenant_id
body["auth"]["scope"] = scope
else:
body = {"auth": {
"passwordCredentials": {"username": self.user,
"password": self.password}}}
if self.projectid:
body['auth']['tenantName'] = self.projectid
elif self.tenant_id:
body['auth']['tenantId'] = self.tenant_id
return self._authenticate(url, body)
def _authenticate(self, url, body):
"""Authenticate and extract the service catalog."""
if self.ks_version == 'v3':
token_url = url + "/auth/tokens"
else:
token_url = url + "/tokens"
# Make sure we follow redirects when trying to reach Keystone
resp, body = self.request(
token_url,
"POST",
body=body,
allow_redirects=True)
return self._extract_service_catalog(url, resp, body)
def _construct_http_client(username=None, password=None, project_id=None,
auth_url=None, insecure=False, timeout=None,
proxy_tenant_id=None, proxy_token=None,
region_name=None, endpoint_type='publicURL',
service_type='volume',
service_name=None, volume_service_name=None,
os_endpoint=None, retries=None,
http_log_debug=False,
auth_system='keystone', auth_plugin=None,
cacert=None, cert=None, tenant_id=None,
session=None,
auth=None, api_version=None,
**kwargs):
if session:
kwargs.setdefault('user_agent', 'python-cinderclient')
kwargs.setdefault('interface', endpoint_type)
kwargs.setdefault('endpoint_override', os_endpoint)
return SessionClient(session=session,
auth=auth,
service_type=service_type,
service_name=service_name,
region_name=region_name,
retries=retries,
api_version=api_version,
**kwargs)
else:
# FIXME(jamielennox): username and password are now optional. Need
# to test that they were provided in this mode.
logger = kwargs.get('logger')
return HTTPClient(username,
password,
projectid=project_id,
auth_url=auth_url,
insecure=insecure,
timeout=timeout,
tenant_id=tenant_id,
proxy_token=proxy_token,
proxy_tenant_id=proxy_tenant_id,
region_name=region_name,
endpoint_type=endpoint_type,
service_type=service_type,
service_name=service_name,
volume_service_name=volume_service_name,
os_endpoint=os_endpoint,
retries=retries,
http_log_debug=http_log_debug,
cacert=cacert,
cert=cert,
auth_system=auth_system,
auth_plugin=auth_plugin,
logger=logger,
api_version=api_version
)
def _get_client_class_and_version(version):
if not isinstance(version, api_versions.APIVersion):
version = api_versions.get_api_version(version)
else:
api_versions.check_major_version(version)
if version.is_latest():
raise exceptions.UnsupportedVersion(
_("The version should be explicit, not latest."))
return version, importutils.import_class(
"cinderclient.v%s.client.Client" % version.ver_major)
def get_client_class(version):
version_map = {
'2': 'cinderclient.v2.client.Client',
'3': 'cinderclient.v3.client.Client',
}
try:
client_path = version_map[str(version)]
except (KeyError, ValueError):
msg = "Invalid client version '%s'. must be one of: %s" % (
(version, ', '.join(version_map)))
raise exceptions.UnsupportedVersion(msg)
return importutils.import_class(client_path)
def discover_extensions(version):
extensions = []
for name, module in itertools.chain(
_discover_via_python_path(),
_discover_via_contrib_path(version)):
extension = cinderclient.extension.Extension(name, module)
extensions.append(extension)
return extensions
def _discover_via_python_path():
for (module_loader, name, ispkg) in pkgutil.iter_modules():
if name.endswith('cinderclient_ext'):
if not hasattr(module_loader, 'load_module'):
# Python 2.6 compat: actually get an ImpImporter obj
module_loader = module_loader.find_module(name)
module = module_loader.load_module(name)
yield name, module
def load_module(name, path):
module_spec = importlib.util.spec_from_file_location(
name, path
)
module = importlib.util.module_from_spec(module_spec)
module_spec.loader.exec_module(module)
return module
def _discover_via_contrib_path(version):
module_path = os.path.dirname(os.path.abspath(__file__))
version_str = "v%s" % version.replace('.', '_')
ext_path = os.path.join(module_path, version_str, 'contrib')
ext_glob = os.path.join(ext_path, "*.py")
for ext_path in glob.iglob(ext_glob):
name = os.path.basename(ext_path)[:-3]
if name == "__init__":
continue
module = load_module(name, ext_path)
yield name, module
def Client(version, *args, **kwargs):
"""Initialize client object based on given version.
HOW-TO:
The simplest way to create a client instance is initialization with your
credentials::
.. code-block:: python
>>> from cinderclient import client
>>> cinder = client.Client(VERSION, USERNAME, PASSWORD,
... PROJECT_NAME, AUTH_URL)
Here ``VERSION`` can be a string or
``cinderclient.api_versions.APIVersion`` obj. If you prefer string value,
you can use ``2`` (deprecated now) or ``3.X`` (where X is a microversion).
Alternatively, you can create a client instance using the keystoneclient
session API. See "The cinderclient Python API" page at
python-cinderclient's doc.
"""
api_version, client_class = _get_client_class_and_version(version)
return client_class(api_version=api_version,
*args, **kwargs)