433 lines
20 KiB
Python
433 lines
20 KiB
Python
# Copyright 2017 Red Hat, Inc.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from http import client as http_client
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import logging
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import re
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import time
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from urllib import parse as urlparse
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import requests
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from sushy import exceptions
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from sushy.taskmonitor import TaskMonitor
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from sushy import utils
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LOG = logging.getLogger(__name__)
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_SERVER_SIDE_RETRIES = 10
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_SERVER_SIDE_RETRY_DELAY = 3
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class Connector(object):
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def __init__(
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self, url, username=None, password=None, verify=True,
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response_callback=None):
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self._url = url
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self._verify = verify
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self._session = requests.Session()
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self._session.verify = self._verify
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self._response_callback = response_callback
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self._auth = None
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# NOTE(TheJulia): In order to help prevent recursive post operations
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# by allowing us to understand that we should stop authentication.
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self._sessions_uri = None
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# NOTE(etingof): field studies reveal that some BMCs choke at
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# long-running persistent HTTP connections (or TCP connections).
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# By default, we ask HTTP server to shut down HTTP connection we've
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# just used.
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self._session.headers['Connection'] = 'close'
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# NOTE(TheJulia): Depending on the BMC, offering compression as an
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# acceptable response changes the ETag behavior to offering an
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# automatic "weak" ETag response, which is appropriate because the
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# body content *may* not be a byte for byte match given compression.
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# Overall, the value of compression is less than the value of concise
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# interaction with the BMC. Setting to identity basically means
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# "without modification or compression". By default, python-requests
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# indicates responses can be compressed.
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self._session.headers['Accept-Encoding'] = 'identity'
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if username or password:
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LOG.warning('Passing username and password to Connector is '
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'deprecated. Authentication is passed through '
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'set_auth now, support for these arguments will '
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'be removed in the future')
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self.set_http_basic_auth(username, password)
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def set_auth(self, auth):
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"""Sets the authentication mechanism for our connector."""
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self._auth = auth
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def set_http_basic_auth(self, username, password):
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"""Sets the http basic authentication information."""
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self._session.auth = (username, password)
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def set_http_session_auth(self, session_auth_token):
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"""Sets the session authentication information."""
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self._session.auth = None
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self._session.headers.update({'X-Auth-Token': session_auth_token})
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def close(self):
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"""Close this connector and the associated HTTP session."""
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self._session.close()
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def check_retry_on_exception(self, exception_msg):
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"""Checks whether retry on exception is required."""
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if ('SYS518' in str(exception_msg)):
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LOG.debug('iDRAC is not yet ready after previous operation. '
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'Error: %(err)s', {'err': str(exception_msg)})
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return True
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else:
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return False
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def _op(self, method, path='', data=None, headers=None, blocking=False,
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timeout=60, server_side_retries=_SERVER_SIDE_RETRIES,
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allow_reauth=True,
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**extra_session_req_kwargs):
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"""Generic RESTful request handler.
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:param method: The HTTP method to be used, e.g: GET, POST,
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PUT, PATCH, etc...
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:param path: The sub-URI or absolute URL path to the resource.
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:param data: Optional JSON data.
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:param headers: Optional dictionary of headers.
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:param blocking: Whether to block for asynchronous operations.
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:param timeout: Max time in seconds to wait for blocking async call.
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:param allow_reauth: Whether to allow refreshing the authentication
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token.
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:param extra_session_req_kwargs: Optional keyword argument to pass
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requests library arguments which would pass on to requests session
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object.
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:returns: The response object from the requests library.
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:raises: ConnectionError
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:raises: HTTPError
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"""
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url = path if urlparse.urlparse(path).netloc else urlparse.urljoin(
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self._url, path)
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headers = headers or {}
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lc_headers = [k.lower() for k in headers]
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if data is not None and 'content-type' not in lc_headers:
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headers['Content-Type'] = 'application/json'
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if 'odata-version' not in lc_headers:
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headers['OData-Version'] = '4.0'
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# TODO(lucasagomes): We should mask the data to remove sensitive
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# information
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LOG.debug('HTTP request: %(method)s %(url)s; headers: %(headers)s; '
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'body: %(data)s; blocking: %(blocking)s; timeout: '
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'%(timeout)s; session arguments: %(session)s;',
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{'method': method, 'url': url,
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'headers': utils.sanitize(headers),
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'data': utils.sanitize(data),
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'blocking': blocking, 'timeout': timeout,
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'session': extra_session_req_kwargs})
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try:
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response = self._session.request(method, url, json=data,
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headers=headers,
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**extra_session_req_kwargs)
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except requests.exceptions.RequestException as e:
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# Capture any general exception by looking for the parent
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# class of exceptions in the requests library.
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# Specifically this will cover cases such as transport
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# failures, connection timeouts, and encoding errors.
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# Raising this as sushy ConnectionError allows users to
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# understand something bad has happened, and to
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# allow them to respond accordingly.
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raise exceptions.ConnectionError(url=url, error=e)
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if self._response_callback:
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self._response_callback(response)
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# If we received an AccessError, and we
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# previously established a redfish session
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# there is a chance that the session has timed-out.
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# Attempt to re-establish a session.
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try:
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exceptions.raise_for_response(method, url, response)
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except exceptions.AccessError as e:
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if (method == 'POST'
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and self._sessions_uri is not None
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and self._sessions_uri in url):
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LOG.error('Authentication to the session service failed. '
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'Please check credentials and try again.')
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raise
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if not allow_reauth:
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LOG.error("Failure occured while attempting to retry "
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"request after refreshing the session: %s", e)
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raise
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if self._auth is not None:
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# self._session.auth value is only set when basic auth is used
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if self._session.auth is not None:
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LOG.warning('We have encountered an AccessError when '
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'using \'basic\' authentication. %(err)s',
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{'err': str(e)})
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# NOTE(TheJulia): There is no way to recover Basic auth,
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# as we need the client to be re-launched with new
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# credentials.
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raise
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try:
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if self._auth.can_refresh_session():
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self._auth.refresh_session()
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else:
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LOG.warning('Session authentication appears to have '
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'been lost at some point in time. '
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'Connectivity may have been lost during '
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'a prior session refresh. Attempting to '
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're-authenticate.')
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self._auth.authenticate()
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except exceptions.AccessError as refresh_exc:
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LOG.error("A failure occured while attempting to refresh "
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"the session. Error: %s", refresh_exc.message)
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raise
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LOG.debug("Authentication refreshed successfully, "
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"retrying the call.")
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return self._op(
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method, path, data=data, headers=headers,
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blocking=blocking, timeout=timeout,
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server_side_retries=server_side_retries - 1,
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allow_reauth=False,
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**extra_session_req_kwargs)
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else:
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if method == 'GET' and url.endswith('SessionService'):
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LOG.debug('HTTP GET of SessionService failed %s, '
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'this is expected prior to authentication',
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e.message)
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else:
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LOG.error("Authentication error detected. Cannot proceed: "
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"%s", e.message)
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raise
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except exceptions.ServerSideError as e:
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if ((method.lower() == 'get'
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or self.check_retry_on_exception(e.message))
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and server_side_retries > 0):
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LOG.warning('Got server side error %s in response to a '
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'GET request, retrying after %d seconds',
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e, _SERVER_SIDE_RETRY_DELAY)
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time.sleep(_SERVER_SIDE_RETRY_DELAY)
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return self._op(method, path, data=data, headers=headers,
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blocking=blocking, timeout=timeout,
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server_side_retries=server_side_retries - 1,
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**extra_session_req_kwargs)
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else:
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raise
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if blocking and response.status_code == 202:
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if not response.headers.get('Location'):
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m = ('HTTP response for %(method)s request to %(url)s '
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'returned status 202, but no Location header'
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% {'method': method, 'url': url})
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raise exceptions.ConnectionError(url=url, error=m)
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mon = TaskMonitor.from_response(self, response, path)
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mon.wait(timeout)
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response = mon.response
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exceptions.raise_for_response(method, url, response)
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LOG.debug('HTTP response for %(method)s %(url)s: '
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'status code: %(code)s',
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{'method': method, 'url': url,
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'code': response.status_code})
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return response
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def get(self, path='', data=None, headers=None, blocking=False,
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timeout=60, **extra_session_req_kwargs):
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"""HTTP GET method.
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:param path: Optional sub-URI path to the resource.
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:param data: Optional JSON data.
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:param headers: Optional dictionary of headers.
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:param blocking: Whether to block for asynchronous operations.
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:param timeout: Max time in seconds to wait for blocking async call.
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:param extra_session_req_kwargs: Optional keyword argument to pass
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requests library arguments which would pass on to requests session
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object.
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:returns: The response object from the requests library.
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:raises: ConnectionError
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:raises: HTTPError
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"""
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return self._op('GET', path, data=data, headers=headers,
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blocking=blocking, timeout=timeout,
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**extra_session_req_kwargs)
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def post(self, path='', data=None, headers=None, blocking=False,
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timeout=60, **extra_session_req_kwargs):
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"""HTTP POST method.
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:param path: Optional sub-URI path to the resource.
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:param data: Optional JSON data.
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:param headers: Optional dictionary of headers.
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:param blocking: Whether to block for asynchronous operations.
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:param timeout: Max time in seconds to wait for blocking async call.
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:param extra_session_req_kwargs: Optional keyword argument to pass
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requests library arguments which would pass on to requests session
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object.
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:returns: The response object from the requests library.
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:raises: ConnectionError
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:raises: HTTPError
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"""
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return self._op('POST', path, data=data, headers=headers,
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blocking=blocking, timeout=timeout,
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**extra_session_req_kwargs)
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def _etag_handler(self, path='', data=None, headers=None, etag=None,
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blocking=False, timeout=60, **extra_session_req_kwargs):
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"""eTag handler containing workarounds for PATCH requests with eTags.
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:param path: Optional sub-URI path to the resource.
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:param data: Optional JSON data.
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:param headers: Optional dictionary of headers.
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:param etag: eTag string.
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:param blocking: Whether to block for asynchronous operations.
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:param timeout: Max time in seconds to wait for blocking async call.
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:param extra_session_req_kwargs: Optional keyword argument to pass
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requests library arguments which would pass on to requests session
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object.
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:returns: The response object from the requests library.
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:raises: ConnectionError
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:raises: HTTPError
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"""
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if etag is not None:
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if not headers:
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headers = {}
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headers['If-Match'] = etag
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try:
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response = self._op('PATCH', path, data=data,
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headers=headers,
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blocking=blocking, timeout=timeout,
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**extra_session_req_kwargs)
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except exceptions.HTTPError as resp:
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LOG.warning("Initial request with eTag failed: %s",
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resp)
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if resp.status_code == http_client.PRECONDITION_FAILED:
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# NOTE(janders) if there was no eTag provided AND the response
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# is HTTP 412 Precondition Failed, raise the exception
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if not etag:
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raise
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# checking for weak eTag
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pattern = re.compile(r'^(W\/)("\w*")$')
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match = pattern.match(etag)
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if match:
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LOG.info("Weak eTag provided with original request to "
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"%s. Attempting to conversion to strong eTag "
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"and re-trying.", path)
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# trying weak eTag converted to strong
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headers['If-Match'] = match.group(2)
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try:
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response = self._op('PATCH', path, data=data,
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headers=headers,
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blocking=blocking,
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timeout=timeout,
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**extra_session_req_kwargs)
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except exceptions.HTTPError as resp:
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if (resp.status_code == http_client.
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PRECONDITION_FAILED):
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LOG.warning("Request to %s with weak eTag "
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"converted to strong eTag also "
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"failed. Making the final attempt "
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"with no eTag specified.", path)
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response = None
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if response:
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return response
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else:
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# eTag is strong, if it failed the only other thing
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# to try is removing it entirely
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# info
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LOG.warning("Strong eTag provided - retrying request to "
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"%s with eTag removed.", path)
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del headers['If-Match']
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try:
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response = self._op('PATCH', path, data=data,
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headers=headers,
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blocking=blocking, timeout=timeout,
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**extra_session_req_kwargs)
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except exceptions.HTTPError as resp:
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LOG.error("Final re-try with eTag removed has failed, "
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"raising exception %s", resp)
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raise
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else:
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raise
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return response
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def patch(self, path='', data=None, headers=None, etag=None,
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blocking=False, timeout=60, **extra_session_req_kwargs):
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"""HTTP PATCH method.
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:param path: Optional sub-URI path to the resource.
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:param data: Optional JSON data.
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:param headers: Optional dictionary of headers.
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:param etag: Optional eTag string.
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:param blocking: Whether to block for asynchronous operations.
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:param timeout: Max time in seconds to wait for blocking async call.
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:param extra_session_req_kwargs: Optional keyword argument to pass
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requests library arguments which would pass on to requests session
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object.
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:returns: The response object from the requests library.
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:raises: ConnectionError
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:raises: HTTPError
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"""
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return self._etag_handler(path, data,
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headers, etag,
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blocking, timeout,
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**extra_session_req_kwargs)
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def put(self, path='', data=None, headers=None, blocking=False,
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timeout=60, **extra_session_req_kwargs):
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"""HTTP PUT method.
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:param path: Optional sub-URI path to the resource.
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:param data: Optional JSON data.
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:param headers: Optional dictionary of headers.
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:param blocking: Whether to block for asynchronous operations.
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:param timeout: Max time in seconds to wait for blocking async call.
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:param extra_session_req_kwargs: Optional keyword argument to pass
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requests library arguments which would pass on to requests session
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object.
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:returns: The response object from the requests library.
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:raises: ConnectionError
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:raises: HTTPError
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"""
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return self._op('PUT', path, data=data, headers=headers,
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blocking=blocking, timeout=timeout,
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**extra_session_req_kwargs)
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def delete(self, path='', data=None, headers=None, blocking=False,
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timeout=60, **extra_session_req_kwargs):
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"""HTTP DELETE method.
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:param path: Optional sub-URI path to the resource.
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:param data: Optional JSON data.
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:param headers: Optional dictionary of headers.
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:param blocking: Whether to block for asynchronous operations.
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:param timeout: Max time in seconds to wait for blocking async call.
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:param extra_session_req_kwargs: Optional keyword argument to pass
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requests library arguments which would pass on to requests session
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object.
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:returns: The response object from the requests library.
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:raises: ConnectionError
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:raises: HTTPError
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"""
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return self._op('DELETE', path, data=data, headers=headers,
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blocking=blocking, timeout=timeout,
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**extra_session_req_kwargs)
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def __enter__(self):
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return self
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def __exit__(self, *_args):
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self.close()
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