472 lines
16 KiB
Python
472 lines
16 KiB
Python
# Copyright 2017 gRPC authors.
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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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"""Implementation of gRPC Python interceptors."""
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import collections
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import sys
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import grpc
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class _ServicePipeline(object):
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def __init__(self, interceptors):
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self.interceptors = tuple(interceptors)
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def _continuation(self, thunk, index):
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return lambda context: self._intercept_at(thunk, index, context)
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def _intercept_at(self, thunk, index, context):
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if index < len(self.interceptors):
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interceptor = self.interceptors[index]
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thunk = self._continuation(thunk, index + 1)
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return interceptor.intercept_service(thunk, context)
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else:
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return thunk(context)
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def execute(self, thunk, context):
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return self._intercept_at(thunk, 0, context)
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def service_pipeline(interceptors):
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return _ServicePipeline(interceptors) if interceptors else None
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class _ClientCallDetails(
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collections.namedtuple(
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'_ClientCallDetails',
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('method', 'timeout', 'metadata', 'credentials')),
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grpc.ClientCallDetails):
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pass
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def _unwrap_client_call_details(call_details, default_details):
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try:
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method = call_details.method
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except AttributeError:
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method = default_details.method
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try:
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timeout = call_details.timeout
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except AttributeError:
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timeout = default_details.timeout
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try:
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metadata = call_details.metadata
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except AttributeError:
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metadata = default_details.metadata
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try:
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credentials = call_details.credentials
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except AttributeError:
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credentials = default_details.credentials
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return method, timeout, metadata, credentials
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class _FailureOutcome(grpc.RpcError, grpc.Future, grpc.Call):
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def __init__(self, exception, traceback):
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super(_FailureOutcome, self).__init__()
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self._exception = exception
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self._traceback = traceback
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def initial_metadata(self):
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return None
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def trailing_metadata(self):
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return None
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def code(self):
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return grpc.StatusCode.INTERNAL
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def details(self):
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return 'Exception raised while intercepting the RPC'
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def cancel(self):
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return False
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def cancelled(self):
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return False
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def is_active(self):
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return False
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def time_remaining(self):
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return None
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def running(self):
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return False
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def done(self):
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return True
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def result(self, ignored_timeout=None):
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raise self._exception
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def exception(self, ignored_timeout=None):
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return self._exception
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def traceback(self, ignored_timeout=None):
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return self._traceback
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def add_callback(self, callback):
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return False
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def add_done_callback(self, fn):
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fn(self)
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def __iter__(self):
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return self
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def next(self):
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raise self._exception
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class _UnaryOutcome(grpc.Call, grpc.Future):
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def __init__(self, response, call):
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self._response = response
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self._call = call
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def initial_metadata(self):
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return self._call.initial_metadata()
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def trailing_metadata(self):
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return self._call.trailing_metadata()
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def code(self):
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return self._call.code()
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def details(self):
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return self._call.details()
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def is_active(self):
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return self._call.is_active()
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def time_remaining(self):
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return self._call.time_remaining()
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def cancel(self):
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return self._call.cancel()
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def add_callback(self, callback):
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return self._call.add_callback(callback)
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def cancelled(self):
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return False
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def running(self):
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return False
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def done(self):
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return True
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def result(self, ignored_timeout=None):
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return self._response
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def exception(self, ignored_timeout=None):
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return None
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def traceback(self, ignored_timeout=None):
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return None
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def add_done_callback(self, fn):
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fn(self)
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class _UnaryUnaryMultiCallable(grpc.UnaryUnaryMultiCallable):
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def __init__(self, thunk, method, interceptor):
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self._thunk = thunk
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self._method = method
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self._interceptor = interceptor
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def __call__(self, request, timeout=None, metadata=None, credentials=None):
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response, ignored_call = self._with_call(
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request,
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timeout=timeout,
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metadata=metadata,
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credentials=credentials)
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return response
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def _with_call(self, request, timeout=None, metadata=None,
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credentials=None):
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client_call_details = _ClientCallDetails(self._method, timeout,
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metadata, credentials)
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def continuation(new_details, request):
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new_method, new_timeout, new_metadata, new_credentials = (
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_unwrap_client_call_details(new_details, client_call_details))
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try:
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response, call = self._thunk(new_method).with_call(
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request,
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timeout=new_timeout,
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metadata=new_metadata,
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credentials=new_credentials)
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return _UnaryOutcome(response, call)
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except grpc.RpcError:
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raise
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except Exception as exception: # pylint:disable=broad-except
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return _FailureOutcome(exception, sys.exc_info()[2])
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call = self._interceptor.intercept_unary_unary(
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continuation, client_call_details, request)
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return call.result(), call
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def with_call(self, request, timeout=None, metadata=None, credentials=None):
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return self._with_call(
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request,
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timeout=timeout,
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metadata=metadata,
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credentials=credentials)
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def future(self, request, timeout=None, metadata=None, credentials=None):
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client_call_details = _ClientCallDetails(self._method, timeout,
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metadata, credentials)
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def continuation(new_details, request):
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new_method, new_timeout, new_metadata, new_credentials = (
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_unwrap_client_call_details(new_details, client_call_details))
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return self._thunk(new_method).future(
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request,
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timeout=new_timeout,
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metadata=new_metadata,
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credentials=new_credentials)
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try:
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return self._interceptor.intercept_unary_unary(
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continuation, client_call_details, request)
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except Exception as exception: # pylint:disable=broad-except
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return _FailureOutcome(exception, sys.exc_info()[2])
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class _UnaryStreamMultiCallable(grpc.UnaryStreamMultiCallable):
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def __init__(self, thunk, method, interceptor):
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self._thunk = thunk
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self._method = method
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self._interceptor = interceptor
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def __call__(self, request, timeout=None, metadata=None, credentials=None):
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client_call_details = _ClientCallDetails(self._method, timeout,
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metadata, credentials)
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def continuation(new_details, request):
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new_method, new_timeout, new_metadata, new_credentials = (
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_unwrap_client_call_details(new_details, client_call_details))
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return self._thunk(new_method)(
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request,
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timeout=new_timeout,
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metadata=new_metadata,
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credentials=new_credentials)
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try:
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return self._interceptor.intercept_unary_stream(
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continuation, client_call_details, request)
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except Exception as exception: # pylint:disable=broad-except
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return _FailureOutcome(exception, sys.exc_info()[2])
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class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
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def __init__(self, thunk, method, interceptor):
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self._thunk = thunk
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self._method = method
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self._interceptor = interceptor
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def __call__(self,
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request_iterator,
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timeout=None,
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metadata=None,
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credentials=None):
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response, ignored_call = self._with_call(
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request_iterator,
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timeout=timeout,
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metadata=metadata,
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credentials=credentials)
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return response
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def _with_call(self,
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request_iterator,
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timeout=None,
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metadata=None,
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credentials=None):
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client_call_details = _ClientCallDetails(self._method, timeout,
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metadata, credentials)
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def continuation(new_details, request_iterator):
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new_method, new_timeout, new_metadata, new_credentials = (
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_unwrap_client_call_details(new_details, client_call_details))
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try:
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response, call = self._thunk(new_method).with_call(
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request_iterator,
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timeout=new_timeout,
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metadata=new_metadata,
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credentials=new_credentials)
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return _UnaryOutcome(response, call)
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except grpc.RpcError:
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raise
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except Exception as exception: # pylint:disable=broad-except
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return _FailureOutcome(exception, sys.exc_info()[2])
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call = self._interceptor.intercept_stream_unary(
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continuation, client_call_details, request_iterator)
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return call.result(), call
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def with_call(self,
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request_iterator,
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timeout=None,
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metadata=None,
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credentials=None):
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return self._with_call(
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request_iterator,
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timeout=timeout,
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metadata=metadata,
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credentials=credentials)
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def future(self,
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request_iterator,
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timeout=None,
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metadata=None,
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credentials=None):
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client_call_details = _ClientCallDetails(self._method, timeout,
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metadata, credentials)
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def continuation(new_details, request_iterator):
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new_method, new_timeout, new_metadata, new_credentials = (
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_unwrap_client_call_details(new_details, client_call_details))
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return self._thunk(new_method).future(
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request_iterator,
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timeout=new_timeout,
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metadata=new_metadata,
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credentials=new_credentials)
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try:
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return self._interceptor.intercept_stream_unary(
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continuation, client_call_details, request_iterator)
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except Exception as exception: # pylint:disable=broad-except
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return _FailureOutcome(exception, sys.exc_info()[2])
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class _StreamStreamMultiCallable(grpc.StreamStreamMultiCallable):
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def __init__(self, thunk, method, interceptor):
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self._thunk = thunk
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self._method = method
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self._interceptor = interceptor
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def __call__(self,
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request_iterator,
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timeout=None,
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metadata=None,
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credentials=None):
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client_call_details = _ClientCallDetails(self._method, timeout,
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metadata, credentials)
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def continuation(new_details, request_iterator):
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new_method, new_timeout, new_metadata, new_credentials = (
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_unwrap_client_call_details(new_details, client_call_details))
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return self._thunk(new_method)(
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request_iterator,
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timeout=new_timeout,
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metadata=new_metadata,
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credentials=new_credentials)
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try:
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return self._interceptor.intercept_stream_stream(
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continuation, client_call_details, request_iterator)
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except Exception as exception: # pylint:disable=broad-except
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return _FailureOutcome(exception, sys.exc_info()[2])
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class _Channel(grpc.Channel):
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def __init__(self, channel, interceptor):
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self._channel = channel
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self._interceptor = interceptor
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def subscribe(self, callback, try_to_connect=False):
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self._channel.subscribe(callback, try_to_connect=try_to_connect)
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def unsubscribe(self, callback):
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self._channel.unsubscribe(callback)
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def unary_unary(self,
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method,
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request_serializer=None,
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response_deserializer=None):
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thunk = lambda m: self._channel.unary_unary(m, request_serializer, response_deserializer)
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if isinstance(self._interceptor, grpc.UnaryUnaryClientInterceptor):
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return _UnaryUnaryMultiCallable(thunk, method, self._interceptor)
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else:
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return thunk(method)
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def unary_stream(self,
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method,
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request_serializer=None,
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response_deserializer=None):
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thunk = lambda m: self._channel.unary_stream(m, request_serializer, response_deserializer)
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if isinstance(self._interceptor, grpc.UnaryStreamClientInterceptor):
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return _UnaryStreamMultiCallable(thunk, method, self._interceptor)
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else:
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return thunk(method)
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def stream_unary(self,
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method,
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request_serializer=None,
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response_deserializer=None):
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thunk = lambda m: self._channel.stream_unary(m, request_serializer, response_deserializer)
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if isinstance(self._interceptor, grpc.StreamUnaryClientInterceptor):
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return _StreamUnaryMultiCallable(thunk, method, self._interceptor)
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else:
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return thunk(method)
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def stream_stream(self,
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method,
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request_serializer=None,
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response_deserializer=None):
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thunk = lambda m: self._channel.stream_stream(m, request_serializer, response_deserializer)
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if isinstance(self._interceptor, grpc.StreamStreamClientInterceptor):
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return _StreamStreamMultiCallable(thunk, method, self._interceptor)
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else:
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return thunk(method)
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def _close(self):
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self._channel.close()
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def __enter__(self):
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return self
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def __exit__(self, exc_type, exc_val, exc_tb):
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self._close()
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return False
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def close(self):
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self._channel.close()
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def intercept_channel(channel, *interceptors):
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for interceptor in reversed(list(interceptors)):
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if not isinstance(interceptor, grpc.UnaryUnaryClientInterceptor) and \
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not isinstance(interceptor, grpc.UnaryStreamClientInterceptor) and \
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not isinstance(interceptor, grpc.StreamUnaryClientInterceptor) and \
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not isinstance(interceptor, grpc.StreamStreamClientInterceptor):
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raise TypeError('interceptor must be '
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'grpc.UnaryUnaryClientInterceptor or '
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'grpc.UnaryStreamClientInterceptor or '
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'grpc.StreamUnaryClientInterceptor or '
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'grpc.StreamStreamClientInterceptor or ')
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channel = _Channel(channel, interceptor)
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return channel
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