openstack/python-ironicclient
Code Issues Proposed changes
8b453ff88a
python-ironicclient/ironicclient/common/http.py
Devananda van der Veen 8b453ff88a Client should fall back to the lower versions if necessary 
The python client should catch 406 Not Acceptable errors when talking to
older versions of the server. If the user did not request a specific
version, the client should negotiate (fall back to) a mutually supported
API version with the server.

If there is no mutually supported version, or if the user specified a
version in which the requested feature is unavailable, the client should
raise an error.

This patch is a partial implementation of the client side of
auto-negotiation. It catches the 406 error and attempts to determine
what version the server is based on the returned headers. It does NOT
actually change what values are sent or returned by the client, aside
from the version headers.

Without this fix, the client fails to connect to any server version
between commit 41595327 (when v1.1 was introduced) and commit 6ecee368
(when v1.6 was introduced), because it is requesting API version 1.6
and not handling the 406 Not Acceptable response.

Note that API server versions prior to commit 32fb6e99 did not return
any version information in the header of a 406 Not Acceptable response.
To work around this, when the client receives a 406 response that does
not contain any version header, the client performs an extra GET request
to the root /v1/ URL to retrieve the supported versions. This allows the
client to work with API services that might be running unreleased
mid-kilo code as well as both stable/juno and the latest kilo code.

Co-Authored-By: Dmitry Tantsur <dtantsur@redhat.com>
Co-Authored-By: John L. Villalovos <john.l.villalovos@intel.com>
Change-Id: Iab6a0814f0db6dd6e7bfc00da28baf8403a6b1db
Blueprint: api-microversions
Partial-bug: #1441170
2015-04-13 10:31:47 -07:00

515 lines
20 KiB
Python
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# -*- coding: utf-8 -*-
#
# 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 copy
import json
import logging
import os
import socket
import ssl
import textwrap
from keystoneclient import adapter
import six
import six.moves.urllib.parse as urlparse
from ironicclient import exc
# NOTE(deva): Record the latest version that this client was tested with.
# We still have a lot of work to do in the client to implement
# microversion support in the client properly! See
# http://specs.openstack.org/openstack/ironic-specs/specs/kilo/api-microversions.html # noqa
# for full details.
DEFAULT_VER = '1.6'
LOG = logging.getLogger(__name__)
USER_AGENT = 'python-ironicclient'
CHUNKSIZE = 1024 * 64 # 64kB
API_VERSION = '/v1'
API_VERSION_SELECTED_STATES = ('user', 'negotiated', 'default')
def _trim_endpoint_api_version(url):
"""Trim API version and trailing slash from endpoint."""
return url.rstrip('/').rstrip(API_VERSION)
def _extract_error_json(body):
"""Return error_message from the HTTP response body."""
error_json = {}
try:
body_json = json.loads(body)
if 'error_message' in body_json:
raw_msg = body_json['error_message']
error_json = json.loads(raw_msg)
except ValueError:
pass
return error_json
class VersionNegotiationMixin(object):
def negotiate_version(self, conn, resp):
"""Negotiate the server version
Assumption: Called after receiving a 406 error when doing a request.
param conn: A connection object
param resp: The response object from http request
"""
if self.api_version_select_state not in API_VERSION_SELECTED_STATES:
raise RuntimeError(
'Error: self.api_version_select_state should be one of the '
'values in: "%(valid)s" but had the value: "%(value)s"' %
{'valid': ', '.join(API_VERSION_SELECTED_STATES),
'value': self.api_version_select_state})
min_ver, max_ver = self._parse_version_headers(resp)
# NOTE: servers before commit 32fb6e99 did not return version headers
# on error, so we need to perform a GET to determine
# the supported version range
if not max_ver:
LOG.debug('No version header in response, requesting from server')
if self.os_ironic_api_version:
base_version = ("/v%s" %
str(self.os_ironic_api_version).split('.')[0])
else:
base_version = API_VERSION
resp = self._make_simple_request(conn, 'GET', base_version)
min_ver, max_ver = self._parse_version_headers(resp)
# If the user requested an explicit version or we have negotiated a
# version and still failing then error now. The server could
# support the version requested but the requested operation may not
# be supported by the requested version.
if self.api_version_select_state == 'user':
raise exc.UnsupportedVersion(textwrap.fill(
"Requested API version %(req)s is not supported by the "
"server or the requested operation is not supported by the "
"requested version. Supported version range is %(min)s to "
"%(max)s"
% {'req': self.os_ironic_api_version,
'min': min_ver, 'max': max_ver}))
if self.api_version_select_state == 'negotiated':
raise exc.UnsupportedVersion(textwrap.fill(
"No API version was specified and the requested operation was "
"not supported by the client's negotiated API version "
"%(req)s. Supported version range is: %(min)s to %(max)s"
% {'req': self.os_ironic_api_version,
'min': min_ver, 'max': max_ver}))
# TODO(deva): cache the negotiated version for this server
negotiated_ver = min(self.os_ironic_api_version, max_ver)
if negotiated_ver < min_ver:
negotiated_ver = min_ver
# server handles microversions, but doesn't support
# the requested version, so try a negotiated version
self.api_version_select_state = 'negotiated'
self.os_ironic_api_version = negotiated_ver
LOG.debug('Negotiated API version is %s', negotiated_ver)
return negotiated_ver
def _generic_parse_version_headers(self, accessor_func):
min_ver = accessor_func('X-OpenStack-Ironic-API-Minimum-Version',
None)
max_ver = accessor_func('X-OpenStack-Ironic-API-Maximum-Version',
None)
return min_ver, max_ver
def _parse_version_headers(self, accessor_func):
# NOTE(jlvillal): Declared for unit testing purposes
raise NotImplementedError()
def _make_simple_request(self, conn, method, url):
# NOTE(jlvillal): Declared for unit testing purposes
raise NotImplementedError()
class HTTPClient(VersionNegotiationMixin):
def __init__(self, endpoint, **kwargs):
self.endpoint = endpoint
self.endpoint_trimmed = _trim_endpoint_api_version(endpoint)
self.auth_token = kwargs.get('token')
self.auth_ref = kwargs.get('auth_ref')
self.os_ironic_api_version = kwargs.get('os_ironic_api_version',
DEFAULT_VER)
self.api_version_select_state = kwargs.get(
'api_version_select_state', 'default')
self.connection_params = self.get_connection_params(endpoint, **kwargs)
@staticmethod
def get_connection_params(endpoint, **kwargs):
parts = urlparse.urlparse(endpoint)
path = _trim_endpoint_api_version(parts.path)
_args = (parts.hostname, parts.port, path)
_kwargs = {'timeout': (float(kwargs.get('timeout'))
if kwargs.get('timeout') else 600)}
if parts.scheme == 'https':
_class = VerifiedHTTPSConnection
_kwargs['ca_file'] = kwargs.get('ca_file', None)
_kwargs['cert_file'] = kwargs.get('cert_file', None)
_kwargs['key_file'] = kwargs.get('key_file', None)
_kwargs['insecure'] = kwargs.get('insecure', False)
elif parts.scheme == 'http':
_class = six.moves.http_client.HTTPConnection
else:
msg = 'Unsupported scheme: %s' % parts.scheme
raise exc.EndpointException(msg)
return (_class, _args, _kwargs)
def get_connection(self):
_class = self.connection_params[0]
try:
return _class(*self.connection_params[1][0:2],
**self.connection_params[2])
except six.moves.http_client.InvalidURL:
raise exc.EndpointException()
def log_curl_request(self, method, url, kwargs):
curl = ['curl -i -X %s' % method]
for (key, value) in kwargs['headers'].items():
header = '-H \'%s: %s\'' % (key, value)
curl.append(header)
conn_params_fmt = [
('key_file', '--key %s'),
('cert_file', '--cert %s'),
('ca_file', '--cacert %s'),
]
for (key, fmt) in conn_params_fmt:
value = self.connection_params[2].get(key)
if value:
curl.append(fmt % value)
if self.connection_params[2].get('insecure'):
curl.append('-k')
if 'body' in kwargs:
curl.append('-d \'%s\'' % kwargs['body'])
curl.append(urlparse.urljoin(self.endpoint_trimmed, url))
LOG.debug(' '.join(curl))
@staticmethod
def log_http_response(resp, body=None):
status = (resp.version / 10.0, resp.status, resp.reason)
dump = ['\nHTTP/%.1f %s %s' % status]
dump.extend(['%s: %s' % (k, v) for k, v in resp.getheaders()])
dump.append('')
if body:
dump.extend([body, ''])
LOG.debug('\n'.join(dump))
def _make_connection_url(self, url):
(_class, _args, _kwargs) = self.connection_params
base_url = _args[2]
return '%s/%s' % (base_url, url.lstrip('/'))
def _parse_version_headers(self, resp):
return self._generic_parse_version_headers(resp.getheader)
def _make_simple_request(self, conn, method, url):
conn.request(method, self._make_connection_url(url))
return conn.getresponse()
def _http_request(self, url, method, **kwargs):
"""Send an http request with the specified characteristics.
Wrapper around httplib.HTTP(S)Connection.request to handle tasks such
as setting headers and error handling.
"""
# Copy the kwargs so we can reuse the original in case of redirects
kwargs['headers'] = copy.deepcopy(kwargs.get('headers', {}))
kwargs['headers'].setdefault('User-Agent', USER_AGENT)
if self.os_ironic_api_version:
kwargs['headers'].setdefault('X-OpenStack-Ironic-API-Version',
self.os_ironic_api_version)
if self.auth_token:
kwargs['headers'].setdefault('X-Auth-Token', self.auth_token)
self.log_curl_request(method, url, kwargs)
conn = self.get_connection()
try:
conn_url = self._make_connection_url(url)
conn.request(method, conn_url, **kwargs)
resp = conn.getresponse()
# TODO(deva): implement graceful client downgrade when connecting
# to servers that did not support microversions. Details here:
# http://specs.openstack.org/openstack/ironic-specs/specs/kilo/api-microversions.html#use-case-3b-new-client-communicating-with-a-old-ironic-user-specified # noqa
if resp.status == 406:
negotiated_ver = self.negotiate_version(conn, resp)
kwargs['headers']['X-OpenStack-Ironic-API-Version'] = (
negotiated_ver)
return self._http_request(url, method, **kwargs)
except socket.gaierror as e:
message = ("Error finding address for %(url)s: %(e)s"
% dict(url=url, e=e))
raise exc.EndpointNotFound(message)
except (socket.error, socket.timeout) as e:
endpoint = self.endpoint
message = ("Error communicating with %(endpoint)s %(e)s"
% dict(endpoint=endpoint, e=e))
raise exc.ConnectionRefused(message)
body_iter = ResponseBodyIterator(resp)
# Read body into string if it isn't obviously image data
body_str = None
if resp.getheader('content-type', None) != 'application/octet-stream':
body_str = ''.join([chunk for chunk in body_iter])
self.log_http_response(resp, body_str)
body_iter = six.StringIO(body_str)
else:
self.log_http_response(resp)
if 400 <= resp.status < 600:
LOG.warn("Request returned failure status.")
error_json = _extract_error_json(body_str)
raise exc.from_response(
resp, error_json.get('faultstring'),
error_json.get('debuginfo'), method, url)
elif resp.status in (301, 302, 305):
# Redirected. Reissue the request to the new location.
return self._http_request(resp['location'], method, **kwargs)
elif resp.status == 300:
raise exc.from_response(resp, method=method, url=url)
return resp, body_iter
def json_request(self, method, url, **kwargs):
kwargs.setdefault('headers', {})
kwargs['headers'].setdefault('Content-Type', 'application/json')
kwargs['headers'].setdefault('Accept', 'application/json')
if 'body' in kwargs:
kwargs['body'] = json.dumps(kwargs['body'])
resp, body_iter = self._http_request(url, method, **kwargs)
content_type = resp.getheader('content-type', None)
if resp.status == 204 or resp.status == 205 or content_type is None:
return resp, list()
if 'application/json' in content_type:
body = ''.join([chunk for chunk in body_iter])
try:
body = json.loads(body)
except ValueError:
LOG.error('Could not decode response body as JSON')
else:
body = None
return resp, body
def raw_request(self, method, url, **kwargs):
kwargs.setdefault('headers', {})
kwargs['headers'].setdefault('Content-Type',
'application/octet-stream')
return self._http_request(url, method, **kwargs)
class VerifiedHTTPSConnection(six.moves.http_client.HTTPSConnection):
"""httplib-compatibile connection using client-side SSL authentication
:see http://code.activestate.com/recipes/
577548-https-httplib-client-connection-with-certificate-v/
"""
def __init__(self, host, port, key_file=None, cert_file=None,
ca_file=None, timeout=None, insecure=False):
six.moves.http_client.HTTPSConnection.__init__(self, host, port,
key_file=key_file,
cert_file=cert_file)
self.key_file = key_file
self.cert_file = cert_file
if ca_file is not None:
self.ca_file = ca_file
else:
self.ca_file = self.get_system_ca_file()
self.timeout = timeout
self.insecure = insecure
def connect(self):
"""Connect to a host on a given (SSL) port.
If ca_file is pointing somewhere, use it to check Server Certificate.
Redefined/copied and extended from httplib.py:1105 (Python 2.6.x).
This is needed to pass cert_reqs=ssl.CERT_REQUIRED as parameter to
ssl.wrap_socket(), which forces SSL to check server certificate against
our client certificate.
"""
sock = socket.create_connection((self.host, self.port), self.timeout)
if self._tunnel_host:
self.sock = sock
self._tunnel()
if self.insecure is True:
kwargs = {'cert_reqs': ssl.CERT_NONE}
else:
kwargs = {'cert_reqs': ssl.CERT_REQUIRED, 'ca_certs': self.ca_file}
if self.cert_file:
kwargs['certfile'] = self.cert_file
if self.key_file:
kwargs['keyfile'] = self.key_file
self.sock = ssl.wrap_socket(sock, **kwargs)
@staticmethod
def get_system_ca_file():
"""Return path to system default CA file."""
# Standard CA file locations for Debian/Ubuntu, RedHat/Fedora,
# Suse, FreeBSD/OpenBSD
ca_path = ['/etc/ssl/certs/ca-certificates.crt',
'/etc/pki/tls/certs/ca-bundle.crt',
'/etc/ssl/ca-bundle.pem',
'/etc/ssl/cert.pem']
for ca in ca_path:
if os.path.exists(ca):
return ca
return None
class SessionClient(VersionNegotiationMixin, adapter.LegacyJsonAdapter):
"""HTTP client based on Keystone client session."""
def _parse_version_headers(self, resp):
return self._generic_parse_version_headers(resp.headers.get)
def _make_simple_request(self, conn, method, url):
# NOTE: conn is self.session for this class
return conn.request(url, method, raise_exc=False)
def _http_request(self, url, method, **kwargs):
kwargs.setdefault('user_agent', USER_AGENT)
kwargs.setdefault('auth', self.auth)
if getattr(self, 'os_ironic_api_version', None):
kwargs['headers'].setdefault('X-OpenStack-Ironic-API-Version',
self.os_ironic_api_version)
endpoint_filter = kwargs.setdefault('endpoint_filter', {})
endpoint_filter.setdefault('interface', self.interface)
endpoint_filter.setdefault('service_type', self.service_type)
endpoint_filter.setdefault('region_name', self.region_name)
resp = self.session.request(url, method,
raise_exc=False, **kwargs)
if resp.status_code == 406:
negotiated_ver = self.negotiate_version(self.session, resp)
kwargs['headers']['X-OpenStack-Ironic-API-Version'] = (
negotiated_ver)
return self._http_request(url, method, **kwargs)
if 400 <= resp.status_code < 600:
error_json = _extract_error_json(resp.content)
raise exc.from_response(resp, error_json.get('faultstring'),
error_json.get('debuginfo'), method, url)
elif resp.status_code in (301, 302, 305):
# Redirected. Reissue the request to the new location.
location = resp.headers.get('location')
resp = self._http_request(location, method, **kwargs)
elif resp.status_code == 300:
raise exc.from_response(resp, method=method, url=url)
return resp
def json_request(self, method, url, **kwargs):
kwargs.setdefault('headers', {})
kwargs['headers'].setdefault('Content-Type', 'application/json')
kwargs['headers'].setdefault('Accept', 'application/json')
if 'body' in kwargs:
kwargs['data'] = json.dumps(kwargs.pop('body'))
resp = self._http_request(url, method, **kwargs)
body = resp.content
content_type = resp.headers.get('content-type', None)
status = resp.status_code
if status == 204 or status == 205 or content_type is None:
return resp, list()
if 'application/json' in content_type:
try:
body = resp.json()
except ValueError:
LOG.error('Could not decode response body as JSON')
else:
body = None
return resp, body
def raw_request(self, method, url, **kwargs):
kwargs.setdefault('headers', {})
kwargs['headers'].setdefault('Content-Type',
'application/octet-stream')
return self._http_request(url, method, **kwargs)
class ResponseBodyIterator(object):
"""A class that acts as an iterator over an HTTP response."""
def __init__(self, resp):
self.resp = resp
def __iter__(self):
while True:
yield self.next()
def next(self):
chunk = self.resp.read(CHUNKSIZE)
if chunk:
return chunk
else:
raise StopIteration()
def _construct_http_client(*args, **kwargs):
session = kwargs.pop('session', None)
auth = kwargs.pop('auth', None)
if session:
service_type = kwargs.pop('service_type', 'baremetal')
interface = kwargs.pop('endpoint_type', None)
region_name = kwargs.pop('region_name', None)
os_ironic_api_version = kwargs.pop('os_ironic_api_version',
DEFAULT_VER)
session_client = SessionClient(session=session,
auth=auth,
interface=interface,
service_type=service_type,
region_name=region_name,
service_name=None,
user_agent='python-ironicclient')
# Append an ironic specific variable to session
session_client.os_ironic_api_version = os_ironic_api_version
session_client.api_version_select_state = (
kwargs.pop('api_version_select_state', 'default'))
return session_client
else:
return HTTPClient(*args, **kwargs)
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