Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/google/auth/transport/grpc.py: 37%
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1# Copyright 2016 Google LLC
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7# http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
15"""Authorization support for gRPC."""
17from __future__ import absolute_import
19import logging
20import os
22import six
24from google.auth import environment_vars
25from google.auth import exceptions
26from google.auth.transport import _mtls_helper
27from google.oauth2 import service_account
29try:
30 import grpc # type: ignore
31except ImportError as caught_exc: # pragma: NO COVER
32 six.raise_from(
33 ImportError(
34 "gRPC is not installed, please install the grpcio package "
35 "to use the gRPC transport."
36 ),
37 caught_exc,
38 )
40_LOGGER = logging.getLogger(__name__)
43class AuthMetadataPlugin(grpc.AuthMetadataPlugin):
44 """A `gRPC AuthMetadataPlugin`_ that inserts the credentials into each
45 request.
47 .. _gRPC AuthMetadataPlugin:
48 http://www.grpc.io/grpc/python/grpc.html#grpc.AuthMetadataPlugin
50 Args:
51 credentials (google.auth.credentials.Credentials): The credentials to
52 add to requests.
53 request (google.auth.transport.Request): A HTTP transport request
54 object used to refresh credentials as needed.
55 default_host (Optional[str]): A host like "pubsub.googleapis.com".
56 This is used when a self-signed JWT is created from service
57 account credentials.
58 """
60 def __init__(self, credentials, request, default_host=None):
61 # pylint: disable=no-value-for-parameter
62 # pylint doesn't realize that the super method takes no arguments
63 # because this class is the same name as the superclass.
64 super(AuthMetadataPlugin, self).__init__()
65 self._credentials = credentials
66 self._request = request
67 self._default_host = default_host
69 def _get_authorization_headers(self, context):
70 """Gets the authorization headers for a request.
72 Returns:
73 Sequence[Tuple[str, str]]: A list of request headers (key, value)
74 to add to the request.
75 """
76 headers = {}
78 # https://google.aip.dev/auth/4111
79 # Attempt to use self-signed JWTs when a service account is used.
80 # A default host must be explicitly provided since it cannot always
81 # be determined from the context.service_url.
82 if isinstance(self._credentials, service_account.Credentials):
83 self._credentials._create_self_signed_jwt(
84 "https://{}/".format(self._default_host) if self._default_host else None
85 )
87 self._credentials.before_request(
88 self._request, context.method_name, context.service_url, headers
89 )
91 return list(six.iteritems(headers))
93 def __call__(self, context, callback):
94 """Passes authorization metadata into the given callback.
96 Args:
97 context (grpc.AuthMetadataContext): The RPC context.
98 callback (grpc.AuthMetadataPluginCallback): The callback that will
99 be invoked to pass in the authorization metadata.
100 """
101 callback(self._get_authorization_headers(context), None)
104def secure_authorized_channel(
105 credentials,
106 request,
107 target,
108 ssl_credentials=None,
109 client_cert_callback=None,
110 **kwargs
111):
112 """Creates a secure authorized gRPC channel.
114 This creates a channel with SSL and :class:`AuthMetadataPlugin`. This
115 channel can be used to create a stub that can make authorized requests.
116 Users can configure client certificate or rely on device certificates to
117 establish a mutual TLS channel, if the `GOOGLE_API_USE_CLIENT_CERTIFICATE`
118 variable is explicitly set to `true`.
120 Example::
122 import google.auth
123 import google.auth.transport.grpc
124 import google.auth.transport.requests
125 from google.cloud.speech.v1 import cloud_speech_pb2
127 # Get credentials.
128 credentials, _ = google.auth.default()
130 # Get an HTTP request function to refresh credentials.
131 request = google.auth.transport.requests.Request()
133 # Create a channel.
134 channel = google.auth.transport.grpc.secure_authorized_channel(
135 credentials, regular_endpoint, request,
136 ssl_credentials=grpc.ssl_channel_credentials())
138 # Use the channel to create a stub.
139 cloud_speech.create_Speech_stub(channel)
141 Usage:
143 There are actually a couple of options to create a channel, depending on if
144 you want to create a regular or mutual TLS channel.
146 First let's list the endpoints (regular vs mutual TLS) to choose from::
148 regular_endpoint = 'speech.googleapis.com:443'
149 mtls_endpoint = 'speech.mtls.googleapis.com:443'
151 Option 1: create a regular (non-mutual) TLS channel by explicitly setting
152 the ssl_credentials::
154 regular_ssl_credentials = grpc.ssl_channel_credentials()
156 channel = google.auth.transport.grpc.secure_authorized_channel(
157 credentials, regular_endpoint, request,
158 ssl_credentials=regular_ssl_credentials)
160 Option 2: create a mutual TLS channel by calling a callback which returns
161 the client side certificate and the key (Note that
162 `GOOGLE_API_USE_CLIENT_CERTIFICATE` environment variable must be explicitly
163 set to `true`)::
165 def my_client_cert_callback():
166 code_to_load_client_cert_and_key()
167 if loaded:
168 return (pem_cert_bytes, pem_key_bytes)
169 raise MyClientCertFailureException()
171 try:
172 channel = google.auth.transport.grpc.secure_authorized_channel(
173 credentials, mtls_endpoint, request,
174 client_cert_callback=my_client_cert_callback)
175 except MyClientCertFailureException:
176 # handle the exception
178 Option 3: use application default SSL credentials. It searches and uses
179 the command in a context aware metadata file, which is available on devices
180 with endpoint verification support (Note that
181 `GOOGLE_API_USE_CLIENT_CERTIFICATE` environment variable must be explicitly
182 set to `true`).
183 See https://cloud.google.com/endpoint-verification/docs/overview::
185 try:
186 default_ssl_credentials = SslCredentials()
187 except:
188 # Exception can be raised if the context aware metadata is malformed.
189 # See :class:`SslCredentials` for the possible exceptions.
191 # Choose the endpoint based on the SSL credentials type.
192 if default_ssl_credentials.is_mtls:
193 endpoint_to_use = mtls_endpoint
194 else:
195 endpoint_to_use = regular_endpoint
196 channel = google.auth.transport.grpc.secure_authorized_channel(
197 credentials, endpoint_to_use, request,
198 ssl_credentials=default_ssl_credentials)
200 Option 4: not setting ssl_credentials and client_cert_callback. For devices
201 without endpoint verification support or `GOOGLE_API_USE_CLIENT_CERTIFICATE`
202 environment variable is not `true`, a regular TLS channel is created;
203 otherwise, a mutual TLS channel is created, however, the call should be
204 wrapped in a try/except block in case of malformed context aware metadata.
206 The following code uses regular_endpoint, it works the same no matter the
207 created channle is regular or mutual TLS. Regular endpoint ignores client
208 certificate and key::
210 channel = google.auth.transport.grpc.secure_authorized_channel(
211 credentials, regular_endpoint, request)
213 The following code uses mtls_endpoint, if the created channle is regular,
214 and API mtls_endpoint is confgured to require client SSL credentials, API
215 calls using this channel will be rejected::
217 channel = google.auth.transport.grpc.secure_authorized_channel(
218 credentials, mtls_endpoint, request)
220 Args:
221 credentials (google.auth.credentials.Credentials): The credentials to
222 add to requests.
223 request (google.auth.transport.Request): A HTTP transport request
224 object used to refresh credentials as needed. Even though gRPC
225 is a separate transport, there's no way to refresh the credentials
226 without using a standard http transport.
227 target (str): The host and port of the service.
228 ssl_credentials (grpc.ChannelCredentials): Optional SSL channel
229 credentials. This can be used to specify different certificates.
230 This argument is mutually exclusive with client_cert_callback;
231 providing both will raise an exception.
232 If ssl_credentials and client_cert_callback are None, application
233 default SSL credentials are used if `GOOGLE_API_USE_CLIENT_CERTIFICATE`
234 environment variable is explicitly set to `true`, otherwise one way TLS
235 SSL credentials are used.
236 client_cert_callback (Callable[[], (bytes, bytes)]): Optional
237 callback function to obtain client certicate and key for mutual TLS
238 connection. This argument is mutually exclusive with
239 ssl_credentials; providing both will raise an exception.
240 This argument does nothing unless `GOOGLE_API_USE_CLIENT_CERTIFICATE`
241 environment variable is explicitly set to `true`.
242 kwargs: Additional arguments to pass to :func:`grpc.secure_channel`.
244 Returns:
245 grpc.Channel: The created gRPC channel.
247 Raises:
248 google.auth.exceptions.MutualTLSChannelError: If mutual TLS channel
249 creation failed for any reason.
250 """
251 # Create the metadata plugin for inserting the authorization header.
252 metadata_plugin = AuthMetadataPlugin(credentials, request)
254 # Create a set of grpc.CallCredentials using the metadata plugin.
255 google_auth_credentials = grpc.metadata_call_credentials(metadata_plugin)
257 if ssl_credentials and client_cert_callback:
258 raise exceptions.MalformedError(
259 "Received both ssl_credentials and client_cert_callback; "
260 "these are mutually exclusive."
261 )
263 # If SSL credentials are not explicitly set, try client_cert_callback and ADC.
264 if not ssl_credentials:
265 use_client_cert = os.getenv(
266 environment_vars.GOOGLE_API_USE_CLIENT_CERTIFICATE, "false"
267 )
268 if use_client_cert == "true" and client_cert_callback:
269 # Use the callback if provided.
270 cert, key = client_cert_callback()
271 ssl_credentials = grpc.ssl_channel_credentials(
272 certificate_chain=cert, private_key=key
273 )
274 elif use_client_cert == "true":
275 # Use application default SSL credentials.
276 adc_ssl_credentils = SslCredentials()
277 ssl_credentials = adc_ssl_credentils.ssl_credentials
278 else:
279 ssl_credentials = grpc.ssl_channel_credentials()
281 # Combine the ssl credentials and the authorization credentials.
282 composite_credentials = grpc.composite_channel_credentials(
283 ssl_credentials, google_auth_credentials
284 )
286 return grpc.secure_channel(target, composite_credentials, **kwargs)
289class SslCredentials:
290 """Class for application default SSL credentials.
292 The behavior is controlled by `GOOGLE_API_USE_CLIENT_CERTIFICATE` environment
293 variable whose default value is `false`. Client certificate will not be used
294 unless the environment variable is explicitly set to `true`. See
295 https://google.aip.dev/auth/4114
297 If the environment variable is `true`, then for devices with endpoint verification
298 support, a device certificate will be automatically loaded and mutual TLS will
299 be established.
300 See https://cloud.google.com/endpoint-verification/docs/overview.
301 """
303 def __init__(self):
304 use_client_cert = os.getenv(
305 environment_vars.GOOGLE_API_USE_CLIENT_CERTIFICATE, "false"
306 )
307 if use_client_cert != "true":
308 self._is_mtls = False
309 else:
310 # Load client SSL credentials.
311 metadata_path = _mtls_helper._check_dca_metadata_path(
312 _mtls_helper.CONTEXT_AWARE_METADATA_PATH
313 )
314 self._is_mtls = metadata_path is not None
316 @property
317 def ssl_credentials(self):
318 """Get the created SSL channel credentials.
320 For devices with endpoint verification support, if the device certificate
321 loading has any problems, corresponding exceptions will be raised. For
322 a device without endpoint verification support, no exceptions will be
323 raised.
325 Returns:
326 grpc.ChannelCredentials: The created grpc channel credentials.
328 Raises:
329 google.auth.exceptions.MutualTLSChannelError: If mutual TLS channel
330 creation failed for any reason.
331 """
332 if self._is_mtls:
333 try:
334 _, cert, key, _ = _mtls_helper.get_client_ssl_credentials()
335 self._ssl_credentials = grpc.ssl_channel_credentials(
336 certificate_chain=cert, private_key=key
337 )
338 except exceptions.ClientCertError as caught_exc:
339 new_exc = exceptions.MutualTLSChannelError(caught_exc)
340 six.raise_from(new_exc, caught_exc)
341 else:
342 self._ssl_credentials = grpc.ssl_channel_credentials()
344 return self._ssl_credentials
346 @property
347 def is_mtls(self):
348 """Indicates if the created SSL channel credentials is mutual TLS."""
349 return self._is_mtls