136 lines
4.9 KiB
Python
136 lines
4.9 KiB
Python
# Copyright 2016 Google Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Authorization support for gRPC."""
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from __future__ import absolute_import
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import six
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try:
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import grpc
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except ImportError as caught_exc: # pragma: NO COVER
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six.raise_from(
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ImportError(
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'gRPC is not installed, please install the grpcio package '
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'to use the gRPC transport.'
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),
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caught_exc,
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)
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class AuthMetadataPlugin(grpc.AuthMetadataPlugin):
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"""A `gRPC AuthMetadataPlugin`_ that inserts the credentials into each
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request.
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.. _gRPC AuthMetadataPlugin:
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http://www.grpc.io/grpc/python/grpc.html#grpc.AuthMetadataPlugin
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Args:
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credentials (google.auth.credentials.Credentials): The credentials to
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add to requests.
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request (google.auth.transport.Request): A HTTP transport request
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object used to refresh credentials as needed.
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"""
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def __init__(self, credentials, request):
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# pylint: disable=no-value-for-parameter
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# pylint doesn't realize that the super method takes no arguments
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# because this class is the same name as the superclass.
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super(AuthMetadataPlugin, self).__init__()
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self._credentials = credentials
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self._request = request
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def _get_authorization_headers(self, context):
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"""Gets the authorization headers for a request.
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Returns:
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Sequence[Tuple[str, str]]: A list of request headers (key, value)
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to add to the request.
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"""
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headers = {}
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self._credentials.before_request(
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self._request,
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context.method_name,
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context.service_url,
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headers)
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return list(six.iteritems(headers))
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def __call__(self, context, callback):
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"""Passes authorization metadata into the given callback.
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Args:
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context (grpc.AuthMetadataContext): The RPC context.
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callback (grpc.AuthMetadataPluginCallback): The callback that will
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be invoked to pass in the authorization metadata.
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"""
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callback(self._get_authorization_headers(context), None)
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def secure_authorized_channel(
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credentials, request, target, ssl_credentials=None, **kwargs):
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"""Creates a secure authorized gRPC channel.
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This creates a channel with SSL and :class:`AuthMetadataPlugin`. This
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channel can be used to create a stub that can make authorized requests.
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Example::
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import google.auth
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import google.auth.transport.grpc
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import google.auth.transport.requests
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from google.cloud.speech.v1 import cloud_speech_pb2
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# Get credentials.
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credentials, _ = google.auth.default()
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# Get an HTTP request function to refresh credentials.
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request = google.auth.transport.requests.Request()
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# Create a channel.
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channel = google.auth.transport.grpc.secure_authorized_channel(
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credentials, 'speech.googleapis.com:443', request)
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# Use the channel to create a stub.
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cloud_speech.create_Speech_stub(channel)
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Args:
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credentials (google.auth.credentials.Credentials): The credentials to
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add to requests.
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request (google.auth.transport.Request): A HTTP transport request
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object used to refresh credentials as needed. Even though gRPC
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is a separate transport, there's no way to refresh the credentials
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without using a standard http transport.
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target (str): The host and port of the service.
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ssl_credentials (grpc.ChannelCredentials): Optional SSL channel
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credentials. This can be used to specify different certificates.
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kwargs: Additional arguments to pass to :func:`grpc.secure_channel`.
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Returns:
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grpc.Channel: The created gRPC channel.
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"""
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# Create the metadata plugin for inserting the authorization header.
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metadata_plugin = AuthMetadataPlugin(credentials, request)
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# Create a set of grpc.CallCredentials using the metadata plugin.
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google_auth_credentials = grpc.metadata_call_credentials(metadata_plugin)
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if ssl_credentials is None:
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ssl_credentials = grpc.ssl_channel_credentials()
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# Combine the ssl credentials and the authorization credentials.
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composite_credentials = grpc.composite_channel_credentials(
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ssl_credentials, google_auth_credentials)
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return grpc.secure_channel(target, composite_credentials, **kwargs)
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