Source code for google.auth.transport.grpc

# Copyright 2016 Google Inc.
#
# 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.

"""Authorization support for gRPC."""

from __future__ import absolute_import

import six
try:
    import grpc
except ImportError as caught_exc:  # pragma: NO COVER
    six.raise_from(
        ImportError(
            'gRPC is not installed, please install the grpcio package '
            'to use the gRPC transport.'
        ),
        caught_exc,
    )


[docs]class AuthMetadataPlugin(grpc.AuthMetadataPlugin): """A `gRPC AuthMetadataPlugin`_ that inserts the credentials into each request. .. _gRPC AuthMetadataPlugin: http://www.grpc.io/grpc/python/grpc.html#grpc.AuthMetadataPlugin Args: credentials (google.auth.credentials.Credentials): The credentials to add to requests. request (google.auth.transport.Request): A HTTP transport request object used to refresh credentials as needed. """ def __init__(self, credentials, request): # pylint: disable=no-value-for-parameter # pylint doesn't realize that the super method takes no arguments # because this class is the same name as the superclass. super(AuthMetadataPlugin, self).__init__() self._credentials = credentials self._request = request def _get_authorization_headers(self, context): """Gets the authorization headers for a request. Returns: Sequence[Tuple[str, str]]: A list of request headers (key, value) to add to the request. """ headers = {} self._credentials.before_request( self._request, context.method_name, context.service_url, headers) return list(six.iteritems(headers)) def __call__(self, context, callback): """Passes authorization metadata into the given callback. Args: context (grpc.AuthMetadataContext): The RPC context. callback (grpc.AuthMetadataPluginCallback): The callback that will be invoked to pass in the authorization metadata. """ callback(self._get_authorization_headers(context), None)
[docs]def secure_authorized_channel( credentials, request, target, ssl_credentials=None, **kwargs): """Creates a secure authorized gRPC channel. This creates a channel with SSL and :class:`AuthMetadataPlugin`. This channel can be used to create a stub that can make authorized requests. Example:: import google.auth import google.auth.transport.grpc import google.auth.transport.requests from google.cloud.speech.v1 import cloud_speech_pb2 # Get credentials. credentials, _ = google.auth.default() # Get an HTTP request function to refresh credentials. request = google.auth.transport.requests.Request() # Create a channel. channel = google.auth.transport.grpc.secure_authorized_channel( credentials, 'speech.googleapis.com:443', request) # Use the channel to create a stub. cloud_speech.create_Speech_stub(channel) Args: credentials (google.auth.credentials.Credentials): The credentials to add to requests. request (google.auth.transport.Request): A HTTP transport request object used to refresh credentials as needed. Even though gRPC is a separate transport, there's no way to refresh the credentials without using a standard http transport. target (str): The host and port of the service. ssl_credentials (grpc.ChannelCredentials): Optional SSL channel credentials. This can be used to specify different certificates. kwargs: Additional arguments to pass to :func:`grpc.secure_channel`. Returns: grpc.Channel: The created gRPC channel. """ # Create the metadata plugin for inserting the authorization header. metadata_plugin = AuthMetadataPlugin(credentials, request) # Create a set of grpc.CallCredentials using the metadata plugin. google_auth_credentials = grpc.metadata_call_credentials(metadata_plugin) if ssl_credentials is None: ssl_credentials = grpc.ssl_channel_credentials() # Combine the ssl credentials and the authorization credentials. composite_credentials = grpc.composite_channel_credentials( ssl_credentials, google_auth_credentials) return grpc.secure_channel(target, composite_credentials, **kwargs)