Source code for google.auth.transport.requests

# Copyright 2016 Google LLC
# 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
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# See the License for the specific language governing permissions and
# limitations under the License.

"""Transport adapter for Requests."""

from __future__ import absolute_import

import functools
import logging
import numbers
import os
import time

    import requests
except ImportError as caught_exc:  # pragma: NO COVER
    import six

            "The requests library is not installed, please install the "
            "requests package to use the requests transport."
import requests.adapters  # pylint: disable=ungrouped-imports
import requests.exceptions  # pylint: disable=ungrouped-imports
from requests.packages.urllib3.util.ssl_ import (
)  # pylint: disable=ungrouped-imports
import six  # pylint: disable=ungrouped-imports

from google.auth import environment_vars
from google.auth import exceptions
from google.auth import transport
import google.auth.transport._mtls_helper
from google.oauth2 import service_account

_LOGGER = logging.getLogger(__name__)

_DEFAULT_TIMEOUT = 120  # in seconds

class _Response(transport.Response):
    """Requests transport response adapter.

        response (requests.Response): The raw Requests response.

    def __init__(self, response):
        self._response = response

    def status(self):
        return self._response.status_code

    def headers(self):
        return self._response.headers

    def data(self):
        return self._response.content

[docs]class TimeoutGuard(object): """A context manager raising an error if the suite execution took too long. Args: timeout (Union[None, Union[float, Tuple[float, float]]]): The maximum number of seconds a suite can run without the context manager raising a timeout exception on exit. If passed as a tuple, the smaller of the values is taken as a timeout. If ``None``, a timeout error is never raised. timeout_error_type (Optional[Exception]): The type of the error to raise on timeout. Defaults to :class:`requests.exceptions.Timeout`. """ def __init__(self, timeout, timeout_error_type=requests.exceptions.Timeout): self._timeout = timeout self.remaining_timeout = timeout self._timeout_error_type = timeout_error_type def __enter__(self): self._start = time.time() return self def __exit__(self, exc_type, exc_value, traceback): if exc_value: return # let the error bubble up automatically if self._timeout is None: return # nothing to do, the timeout was not specified elapsed = time.time() - self._start deadline_hit = False if isinstance(self._timeout, numbers.Number): self.remaining_timeout = self._timeout - elapsed deadline_hit = self.remaining_timeout <= 0 else: self.remaining_timeout = tuple(x - elapsed for x in self._timeout) deadline_hit = min(self.remaining_timeout) <= 0 if deadline_hit: raise self._timeout_error_type()
[docs]class Request(transport.Request): """Requests request adapter. This class is used internally for making requests using various transports in a consistent way. If you use :class:`AuthorizedSession` you do not need to construct or use this class directly. This class can be useful if you want to manually refresh a :class:`~google.auth.credentials.Credentials` instance:: import google.auth.transport.requests import requests request = google.auth.transport.requests.Request() credentials.refresh(request) Args: session (requests.Session): An instance :class:`requests.Session` used to make HTTP requests. If not specified, a session will be created. .. automethod:: __call__ """ def __init__(self, session=None): if not session: session = requests.Session() self.session = session
[docs] def __call__( self, url, method="GET", body=None, headers=None, timeout=_DEFAULT_TIMEOUT, **kwargs ): """Make an HTTP request using requests. Args: url (str): The URI to be requested. method (str): The HTTP method to use for the request. Defaults to 'GET'. body (bytes): The payload or body in HTTP request. headers (Mapping[str, str]): Request headers. timeout (Optional[int]): The number of seconds to wait for a response from the server. If not specified or if None, the requests default timeout will be used. kwargs: Additional arguments passed through to the underlying requests :meth:`~requests.Session.request` method. Returns: google.auth.transport.Response: The HTTP response. Raises: google.auth.exceptions.TransportError: If any exception occurred. """ try: _LOGGER.debug("Making request: %s %s", method, url) response = self.session.request( method, url, data=body, headers=headers, timeout=timeout, **kwargs ) return _Response(response) except requests.exceptions.RequestException as caught_exc: new_exc = exceptions.TransportError(caught_exc) six.raise_from(new_exc, caught_exc)
class _MutualTlsAdapter(requests.adapters.HTTPAdapter): """ A TransportAdapter that enables mutual TLS. Args: cert (bytes): client certificate in PEM format key (bytes): client private key in PEM format Raises: ImportError: if certifi or pyOpenSSL is not installed OpenSSL.crypto.Error: if client cert or key is invalid """ def __init__(self, cert, key): import certifi from OpenSSL import crypto import urllib3.contrib.pyopenssl urllib3.contrib.pyopenssl.inject_into_urllib3() pkey = crypto.load_privatekey(crypto.FILETYPE_PEM, key) x509 = crypto.load_certificate(crypto.FILETYPE_PEM, cert) ctx_poolmanager = create_urllib3_context() ctx_poolmanager.load_verify_locations(cafile=certifi.where()) ctx_poolmanager._ctx.use_certificate(x509) ctx_poolmanager._ctx.use_privatekey(pkey) self._ctx_poolmanager = ctx_poolmanager ctx_proxymanager = create_urllib3_context() ctx_proxymanager.load_verify_locations(cafile=certifi.where()) ctx_proxymanager._ctx.use_certificate(x509) ctx_proxymanager._ctx.use_privatekey(pkey) self._ctx_proxymanager = ctx_proxymanager super(_MutualTlsAdapter, self).__init__() def init_poolmanager(self, *args, **kwargs): kwargs["ssl_context"] = self._ctx_poolmanager super(_MutualTlsAdapter, self).init_poolmanager(*args, **kwargs) def proxy_manager_for(self, *args, **kwargs): kwargs["ssl_context"] = self._ctx_proxymanager return super(_MutualTlsAdapter, self).proxy_manager_for(*args, **kwargs)
[docs]class AuthorizedSession(requests.Session): """A Requests Session class with credentials. This class is used to perform requests to API endpoints that require authorization:: from google.auth.transport.requests import AuthorizedSession authed_session = AuthorizedSession(credentials) response = authed_session.request( 'GET', '') The underlying :meth:`request` implementation handles adding the credentials' headers to the request and refreshing credentials as needed. This class also supports mutual TLS via :meth:`configure_mtls_channel` method. In order to use this method, the `GOOGLE_API_USE_CLIENT_CERTIFICATE` environment variable must be explicitly set to ``true``, otherwise it does nothing. Assume the environment is set to ``true``, the method behaves in the following manner: If client_cert_callback is provided, client certificate and private key are loaded using the callback; if client_cert_callback is None, application default SSL credentials will be used. Exceptions are raised if there are problems with the certificate, private key, or the loading process, so it should be called within a try/except block. First we set the environment variable to ``true``, then create an :class:`AuthorizedSession` instance and specify the endpoints:: regular_endpoint = '{my_project_id}/topics' mtls_endpoint = '{my_project_id}/topics' authed_session = AuthorizedSession(credentials) Now we can pass a callback to :meth:`configure_mtls_channel`:: def my_cert_callback(): # some code to load client cert bytes and private key bytes, both in # PEM format. some_code_to_load_client_cert_and_key() if loaded: return cert, key raise MyClientCertFailureException() # Always call configure_mtls_channel within a try/except block. try: authed_session.configure_mtls_channel(my_cert_callback) except: # handle exceptions. if authed_session.is_mtls: response = authed_session.request('GET', mtls_endpoint) else: response = authed_session.request('GET', regular_endpoint) You can alternatively use application default SSL credentials like this:: try: authed_session.configure_mtls_channel() except: # handle exceptions. Args: credentials (google.auth.credentials.Credentials): The credentials to add to the request. refresh_status_codes (Sequence[int]): Which HTTP status codes indicate that credentials should be refreshed and the request should be retried. max_refresh_attempts (int): The maximum number of times to attempt to refresh the credentials and retry the request. refresh_timeout (Optional[int]): The timeout value in seconds for credential refresh HTTP requests. auth_request (google.auth.transport.requests.Request): (Optional) An instance of :class:`~google.auth.transport.requests.Request` used when refreshing credentials. If not passed, an instance of :class:`~google.auth.transport.requests.Request` is created. default_host (Optional[str]): A host like "". This is used when a self-signed JWT is created from service account credentials. """ def __init__( self, credentials, refresh_status_codes=transport.DEFAULT_REFRESH_STATUS_CODES, max_refresh_attempts=transport.DEFAULT_MAX_REFRESH_ATTEMPTS, refresh_timeout=None, auth_request=None, default_host=None, ): super(AuthorizedSession, self).__init__() self.credentials = credentials self._refresh_status_codes = refresh_status_codes self._max_refresh_attempts = max_refresh_attempts self._refresh_timeout = refresh_timeout self._is_mtls = False self._default_host = default_host if auth_request is None: auth_request_session = requests.Session() # Using an adapter to make HTTP requests robust to network errors. # This adapter retrys HTTP requests when network errors occur # and the requests seems safely retryable. retry_adapter = requests.adapters.HTTPAdapter(max_retries=3) auth_request_session.mount("https://", retry_adapter) # Do not pass `self` as the session here, as it can lead to # infinite recursion. auth_request = Request(auth_request_session) # Request instance used by internal methods (for example, # credentials.refresh). self._auth_request = auth_request # # Attempt to use self-signed JWTs when a service account is used. # A default host must be explicitly provided. if ( isinstance(self.credentials, service_account.Credentials) and self._default_host ): self.credentials._create_self_signed_jwt( "https://{}/".format(self._default_host) )
[docs] def configure_mtls_channel(self, client_cert_callback=None): """Configure the client certificate and key for SSL connection. The function does nothing unless `GOOGLE_API_USE_CLIENT_CERTIFICATE` is explicitly set to `true`. In this case if client certificate and key are successfully obtained (from the given client_cert_callback or from application default SSL credentials), a :class:`_MutualTlsAdapter` instance will be mounted to "https://" prefix. Args: client_cert_callback (Optional[Callable[[], (bytes, bytes)]]): The optional callback returns the client certificate and private key bytes both in PEM format. If the callback is None, application default SSL credentials will be used. Raises: google.auth.exceptions.MutualTLSChannelError: If mutual TLS channel creation failed for any reason. """ use_client_cert = os.getenv( environment_vars.GOOGLE_API_USE_CLIENT_CERTIFICATE, "false" ) if use_client_cert != "true": self._is_mtls = False return try: import OpenSSL except ImportError as caught_exc: new_exc = exceptions.MutualTLSChannelError(caught_exc) six.raise_from(new_exc, caught_exc) try: ( self._is_mtls, cert, key, ) = google.auth.transport._mtls_helper.get_client_cert_and_key( client_cert_callback ) if self._is_mtls: mtls_adapter = _MutualTlsAdapter(cert, key) self.mount("https://", mtls_adapter) except ( exceptions.ClientCertError, ImportError, OpenSSL.crypto.Error, ) as caught_exc: new_exc = exceptions.MutualTLSChannelError(caught_exc) six.raise_from(new_exc, caught_exc)
[docs] def request( self, method, url, data=None, headers=None, max_allowed_time=None, timeout=_DEFAULT_TIMEOUT, **kwargs ): """Implementation of Requests' request. Args: timeout (Optional[Union[float, Tuple[float, float]]]): The amount of time in seconds to wait for the server response with each individual request. Can also be passed as a tuple ``(connect_timeout, read_timeout)``. See :meth:`requests.Session.request` documentation for details. max_allowed_time (Optional[float]): If the method runs longer than this, a ``Timeout`` exception is automatically raised. Unlike the ``timeout`` parameter, this value applies to the total method execution time, even if multiple requests are made under the hood. Mind that it is not guaranteed that the timeout error is raised at ``max_allowed_time``. It might take longer, for example, if an underlying request takes a lot of time, but the request itself does not timeout, e.g. if a large file is being transmitted. The timout error will be raised after such request completes. """ # pylint: disable=arguments-differ # Requests has a ton of arguments to request, but only two # (method, url) are required. We pass through all of the other # arguments to super, so no need to exhaustively list them here. # Use a kwarg for this instead of an attribute to maintain # thread-safety. _credential_refresh_attempt = kwargs.pop("_credential_refresh_attempt", 0) # Make a copy of the headers. They will be modified by the credentials # and we want to pass the original headers if we recurse. request_headers = headers.copy() if headers is not None else {} # Do not apply the timeout unconditionally in order to not override the # _auth_request's default timeout. auth_request = ( self._auth_request if timeout is None else functools.partial(self._auth_request, timeout=timeout) ) remaining_time = max_allowed_time with TimeoutGuard(remaining_time) as guard: self.credentials.before_request(auth_request, method, url, request_headers) remaining_time = guard.remaining_timeout with TimeoutGuard(remaining_time) as guard: response = super(AuthorizedSession, self).request( method, url, data=data, headers=request_headers, timeout=timeout, **kwargs ) remaining_time = guard.remaining_timeout # If the response indicated that the credentials needed to be # refreshed, then refresh the credentials and re-attempt the # request. # A stored token may expire between the time it is retrieved and # the time the request is made, so we may need to try twice. if ( response.status_code in self._refresh_status_codes and _credential_refresh_attempt < self._max_refresh_attempts ): "Refreshing credentials due to a %s response. Attempt %s/%s.", response.status_code, _credential_refresh_attempt + 1, self._max_refresh_attempts, ) # Do not apply the timeout unconditionally in order to not override the # _auth_request's default timeout. auth_request = ( self._auth_request if timeout is None else functools.partial(self._auth_request, timeout=timeout) ) with TimeoutGuard(remaining_time) as guard: self.credentials.refresh(auth_request) remaining_time = guard.remaining_timeout # Recurse. Pass in the original headers, not our modified set, but # do pass the adjusted max allowed time (i.e. the remaining total time). return self.request( method, url, data=data, headers=headers, max_allowed_time=remaining_time, timeout=timeout, _credential_refresh_attempt=_credential_refresh_attempt + 1, **kwargs ) return response
@property def is_mtls(self): """Indicates if the created SSL channel is mutual TLS.""" return self._is_mtls