650 lines
24 KiB
Python
650 lines
24 KiB
Python
# Copyright 2019 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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"""Invocation-side implementation of gRPC Asyncio Python."""
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import asyncio
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import enum
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from functools import partial
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import inspect
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import logging
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import traceback
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from typing import AsyncIterator, Optional, Tuple
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import grpc
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from grpc import _common
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from grpc._cython import cygrpc
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from . import _base_call
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from ._metadata import Metadata
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from ._typing import DeserializingFunction
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from ._typing import DoneCallbackType
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from ._typing import MetadatumType
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from ._typing import RequestIterableType
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from ._typing import RequestType
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from ._typing import ResponseType
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from ._typing import SerializingFunction
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__all__ = 'AioRpcError', 'Call', 'UnaryUnaryCall', 'UnaryStreamCall'
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_LOCAL_CANCELLATION_DETAILS = 'Locally cancelled by application!'
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_GC_CANCELLATION_DETAILS = 'Cancelled upon garbage collection!'
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_RPC_ALREADY_FINISHED_DETAILS = 'RPC already finished.'
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_RPC_HALF_CLOSED_DETAILS = 'RPC is half closed after calling "done_writing".'
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_API_STYLE_ERROR = 'The iterator and read/write APIs may not be mixed on a single RPC.'
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_OK_CALL_REPRESENTATION = ('<{} of RPC that terminated with:\n'
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'\tstatus = {}\n'
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'\tdetails = "{}"\n'
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'>')
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_NON_OK_CALL_REPRESENTATION = ('<{} of RPC that terminated with:\n'
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'\tstatus = {}\n'
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'\tdetails = "{}"\n'
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'\tdebug_error_string = "{}"\n'
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'>')
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_LOGGER = logging.getLogger(__name__)
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class AioRpcError(grpc.RpcError):
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"""An implementation of RpcError to be used by the asynchronous API.
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Raised RpcError is a snapshot of the final status of the RPC, values are
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determined. Hence, its methods no longer needs to be coroutines.
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"""
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_code: grpc.StatusCode
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_details: Optional[str]
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_initial_metadata: Optional[Metadata]
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_trailing_metadata: Optional[Metadata]
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_debug_error_string: Optional[str]
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def __init__(self,
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code: grpc.StatusCode,
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initial_metadata: Metadata,
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trailing_metadata: Metadata,
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details: Optional[str] = None,
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debug_error_string: Optional[str] = None) -> None:
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"""Constructor.
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Args:
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code: The status code with which the RPC has been finalized.
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details: Optional details explaining the reason of the error.
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initial_metadata: Optional initial metadata that could be sent by the
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Server.
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trailing_metadata: Optional metadata that could be sent by the Server.
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"""
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super().__init__()
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self._code = code
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self._details = details
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self._initial_metadata = initial_metadata
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self._trailing_metadata = trailing_metadata
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self._debug_error_string = debug_error_string
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def code(self) -> grpc.StatusCode:
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"""Accesses the status code sent by the server.
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Returns:
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The `grpc.StatusCode` status code.
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"""
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return self._code
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def details(self) -> Optional[str]:
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"""Accesses the details sent by the server.
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Returns:
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The description of the error.
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"""
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return self._details
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def initial_metadata(self) -> Metadata:
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"""Accesses the initial metadata sent by the server.
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Returns:
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The initial metadata received.
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"""
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return self._initial_metadata
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def trailing_metadata(self) -> Metadata:
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"""Accesses the trailing metadata sent by the server.
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Returns:
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The trailing metadata received.
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"""
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return self._trailing_metadata
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def debug_error_string(self) -> str:
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"""Accesses the debug error string sent by the server.
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Returns:
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The debug error string received.
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"""
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return self._debug_error_string
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def _repr(self) -> str:
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"""Assembles the error string for the RPC error."""
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return _NON_OK_CALL_REPRESENTATION.format(self.__class__.__name__,
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self._code, self._details,
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self._debug_error_string)
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def __repr__(self) -> str:
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return self._repr()
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def __str__(self) -> str:
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return self._repr()
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def _create_rpc_error(initial_metadata: Metadata,
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status: cygrpc.AioRpcStatus) -> AioRpcError:
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return AioRpcError(
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_common.CYGRPC_STATUS_CODE_TO_STATUS_CODE[status.code()],
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Metadata.from_tuple(initial_metadata),
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Metadata.from_tuple(status.trailing_metadata()),
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details=status.details(),
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debug_error_string=status.debug_error_string(),
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)
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class Call:
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"""Base implementation of client RPC Call object.
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Implements logic around final status, metadata and cancellation.
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"""
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_loop: asyncio.AbstractEventLoop
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_code: grpc.StatusCode
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_cython_call: cygrpc._AioCall
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_metadata: Tuple[MetadatumType, ...]
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_request_serializer: SerializingFunction
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_response_deserializer: DeserializingFunction
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def __init__(self, cython_call: cygrpc._AioCall, metadata: Metadata,
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request_serializer: SerializingFunction,
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response_deserializer: DeserializingFunction,
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loop: asyncio.AbstractEventLoop) -> None:
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self._loop = loop
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self._cython_call = cython_call
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self._metadata = tuple(metadata)
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self._request_serializer = request_serializer
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self._response_deserializer = response_deserializer
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def __del__(self) -> None:
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# The '_cython_call' object might be destructed before Call object
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if hasattr(self, '_cython_call'):
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if not self._cython_call.done():
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self._cancel(_GC_CANCELLATION_DETAILS)
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def cancelled(self) -> bool:
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return self._cython_call.cancelled()
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def _cancel(self, details: str) -> bool:
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"""Forwards the application cancellation reasoning."""
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if not self._cython_call.done():
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self._cython_call.cancel(details)
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return True
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else:
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return False
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def cancel(self) -> bool:
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return self._cancel(_LOCAL_CANCELLATION_DETAILS)
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def done(self) -> bool:
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return self._cython_call.done()
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def add_done_callback(self, callback: DoneCallbackType) -> None:
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cb = partial(callback, self)
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self._cython_call.add_done_callback(cb)
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def time_remaining(self) -> Optional[float]:
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return self._cython_call.time_remaining()
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async def initial_metadata(self) -> Metadata:
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raw_metadata_tuple = await self._cython_call.initial_metadata()
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return Metadata.from_tuple(raw_metadata_tuple)
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async def trailing_metadata(self) -> Metadata:
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raw_metadata_tuple = (await
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self._cython_call.status()).trailing_metadata()
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return Metadata.from_tuple(raw_metadata_tuple)
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async def code(self) -> grpc.StatusCode:
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cygrpc_code = (await self._cython_call.status()).code()
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return _common.CYGRPC_STATUS_CODE_TO_STATUS_CODE[cygrpc_code]
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async def details(self) -> str:
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return (await self._cython_call.status()).details()
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async def debug_error_string(self) -> str:
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return (await self._cython_call.status()).debug_error_string()
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async def _raise_for_status(self) -> None:
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if self._cython_call.is_locally_cancelled():
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raise asyncio.CancelledError()
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code = await self.code()
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if code != grpc.StatusCode.OK:
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raise _create_rpc_error(await self.initial_metadata(), await
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self._cython_call.status())
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def _repr(self) -> str:
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return repr(self._cython_call)
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def __repr__(self) -> str:
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return self._repr()
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def __str__(self) -> str:
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return self._repr()
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class _APIStyle(enum.IntEnum):
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UNKNOWN = 0
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ASYNC_GENERATOR = 1
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READER_WRITER = 2
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class _UnaryResponseMixin(Call):
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_call_response: asyncio.Task
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def _init_unary_response_mixin(self, response_task: asyncio.Task):
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self._call_response = response_task
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def cancel(self) -> bool:
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if super().cancel():
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self._call_response.cancel()
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return True
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else:
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return False
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def __await__(self) -> ResponseType:
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"""Wait till the ongoing RPC request finishes."""
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try:
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response = yield from self._call_response
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except asyncio.CancelledError:
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# Even if we caught all other CancelledError, there is still
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# this corner case. If the application cancels immediately after
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# the Call object is created, we will observe this
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# `CancelledError`.
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if not self.cancelled():
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self.cancel()
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raise
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# NOTE(lidiz) If we raise RpcError in the task, and users doesn't
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# 'await' on it. AsyncIO will log 'Task exception was never retrieved'.
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# Instead, if we move the exception raising here, the spam stops.
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# Unfortunately, there can only be one 'yield from' in '__await__'. So,
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# we need to access the private instance variable.
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if response is cygrpc.EOF:
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if self._cython_call.is_locally_cancelled():
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raise asyncio.CancelledError()
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else:
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raise _create_rpc_error(self._cython_call._initial_metadata,
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self._cython_call._status)
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else:
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return response
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class _StreamResponseMixin(Call):
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_message_aiter: AsyncIterator[ResponseType]
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_preparation: asyncio.Task
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_response_style: _APIStyle
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def _init_stream_response_mixin(self, preparation: asyncio.Task):
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self._message_aiter = None
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self._preparation = preparation
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self._response_style = _APIStyle.UNKNOWN
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def _update_response_style(self, style: _APIStyle):
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if self._response_style is _APIStyle.UNKNOWN:
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self._response_style = style
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elif self._response_style is not style:
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raise cygrpc.UsageError(_API_STYLE_ERROR)
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def cancel(self) -> bool:
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if super().cancel():
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self._preparation.cancel()
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return True
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else:
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return False
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async def _fetch_stream_responses(self) -> ResponseType:
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message = await self._read()
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while message is not cygrpc.EOF:
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yield message
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message = await self._read()
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# If the read operation failed, Core should explain why.
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await self._raise_for_status()
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def __aiter__(self) -> AsyncIterator[ResponseType]:
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self._update_response_style(_APIStyle.ASYNC_GENERATOR)
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if self._message_aiter is None:
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self._message_aiter = self._fetch_stream_responses()
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return self._message_aiter
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async def _read(self) -> ResponseType:
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# Wait for the request being sent
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await self._preparation
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# Reads response message from Core
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try:
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raw_response = await self._cython_call.receive_serialized_message()
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except asyncio.CancelledError:
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if not self.cancelled():
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self.cancel()
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raise
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if raw_response is cygrpc.EOF:
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return cygrpc.EOF
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else:
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return _common.deserialize(raw_response,
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self._response_deserializer)
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async def read(self) -> ResponseType:
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if self.done():
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await self._raise_for_status()
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return cygrpc.EOF
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self._update_response_style(_APIStyle.READER_WRITER)
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response_message = await self._read()
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if response_message is cygrpc.EOF:
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# If the read operation failed, Core should explain why.
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await self._raise_for_status()
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return response_message
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class _StreamRequestMixin(Call):
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_metadata_sent: asyncio.Event
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_done_writing_flag: bool
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_async_request_poller: Optional[asyncio.Task]
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_request_style: _APIStyle
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def _init_stream_request_mixin(
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self, request_iterator: Optional[RequestIterableType]):
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self._metadata_sent = asyncio.Event()
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self._done_writing_flag = False
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# If user passes in an async iterator, create a consumer Task.
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if request_iterator is not None:
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self._async_request_poller = self._loop.create_task(
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self._consume_request_iterator(request_iterator))
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self._request_style = _APIStyle.ASYNC_GENERATOR
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else:
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self._async_request_poller = None
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self._request_style = _APIStyle.READER_WRITER
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def _raise_for_different_style(self, style: _APIStyle):
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if self._request_style is not style:
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raise cygrpc.UsageError(_API_STYLE_ERROR)
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def cancel(self) -> bool:
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if super().cancel():
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if self._async_request_poller is not None:
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self._async_request_poller.cancel()
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return True
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else:
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return False
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def _metadata_sent_observer(self):
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self._metadata_sent.set()
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async def _consume_request_iterator(
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self, request_iterator: RequestIterableType) -> None:
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try:
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if inspect.isasyncgen(request_iterator) or hasattr(
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request_iterator, '__aiter__'):
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async for request in request_iterator:
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try:
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await self._write(request)
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except AioRpcError as rpc_error:
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_LOGGER.debug(
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'Exception while consuming the request_iterator: %s',
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rpc_error)
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return
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else:
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for request in request_iterator:
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try:
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await self._write(request)
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except AioRpcError as rpc_error:
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_LOGGER.debug(
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'Exception while consuming the request_iterator: %s',
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rpc_error)
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return
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await self._done_writing()
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except: # pylint: disable=bare-except
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# Client iterators can raise exceptions, which we should handle by
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# cancelling the RPC and logging the client's error. No exceptions
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# should escape this function.
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_LOGGER.debug('Client request_iterator raised exception:\n%s',
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traceback.format_exc())
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self.cancel()
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async def _write(self, request: RequestType) -> None:
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if self.done():
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raise asyncio.InvalidStateError(_RPC_ALREADY_FINISHED_DETAILS)
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if self._done_writing_flag:
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raise asyncio.InvalidStateError(_RPC_HALF_CLOSED_DETAILS)
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if not self._metadata_sent.is_set():
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await self._metadata_sent.wait()
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if self.done():
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await self._raise_for_status()
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serialized_request = _common.serialize(request,
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self._request_serializer)
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try:
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await self._cython_call.send_serialized_message(serialized_request)
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except cygrpc.InternalError:
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await self._raise_for_status()
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except asyncio.CancelledError:
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if not self.cancelled():
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self.cancel()
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raise
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async def _done_writing(self) -> None:
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if self.done():
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# If the RPC is finished, do nothing.
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return
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if not self._done_writing_flag:
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# If the done writing is not sent before, try to send it.
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self._done_writing_flag = True
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try:
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await self._cython_call.send_receive_close()
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except asyncio.CancelledError:
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if not self.cancelled():
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self.cancel()
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raise
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async def write(self, request: RequestType) -> None:
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self._raise_for_different_style(_APIStyle.READER_WRITER)
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await self._write(request)
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async def done_writing(self) -> None:
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"""Signal peer that client is done writing.
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This method is idempotent.
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"""
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self._raise_for_different_style(_APIStyle.READER_WRITER)
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await self._done_writing()
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async def wait_for_connection(self) -> None:
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await self._metadata_sent.wait()
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if self.done():
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await self._raise_for_status()
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class UnaryUnaryCall(_UnaryResponseMixin, Call, _base_call.UnaryUnaryCall):
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"""Object for managing unary-unary RPC calls.
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Returned when an instance of `UnaryUnaryMultiCallable` object is called.
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"""
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_request: RequestType
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_invocation_task: asyncio.Task
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# pylint: disable=too-many-arguments
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def __init__(self, request: RequestType, deadline: Optional[float],
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metadata: Metadata,
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credentials: Optional[grpc.CallCredentials],
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wait_for_ready: Optional[bool], channel: cygrpc.AioChannel,
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method: bytes, request_serializer: SerializingFunction,
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response_deserializer: DeserializingFunction,
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loop: asyncio.AbstractEventLoop) -> None:
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super().__init__(
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channel.call(method, deadline, credentials, wait_for_ready),
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metadata, request_serializer, response_deserializer, loop)
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self._request = request
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self._invocation_task = loop.create_task(self._invoke())
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self._init_unary_response_mixin(self._invocation_task)
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async def _invoke(self) -> ResponseType:
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serialized_request = _common.serialize(self._request,
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self._request_serializer)
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# NOTE(lidiz) asyncio.CancelledError is not a good transport for status,
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# because the asyncio.Task class do not cache the exception object.
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# https://github.com/python/cpython/blob/edad4d89e357c92f70c0324b937845d652b20afd/Lib/asyncio/tasks.py#L785
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try:
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serialized_response = await self._cython_call.unary_unary(
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serialized_request, self._metadata)
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except asyncio.CancelledError:
|
|
if not self.cancelled():
|
|
self.cancel()
|
|
|
|
if self._cython_call.is_ok():
|
|
return _common.deserialize(serialized_response,
|
|
self._response_deserializer)
|
|
else:
|
|
return cygrpc.EOF
|
|
|
|
async def wait_for_connection(self) -> None:
|
|
await self._invocation_task
|
|
if self.done():
|
|
await self._raise_for_status()
|
|
|
|
|
|
class UnaryStreamCall(_StreamResponseMixin, Call, _base_call.UnaryStreamCall):
|
|
"""Object for managing unary-stream RPC calls.
|
|
|
|
Returned when an instance of `UnaryStreamMultiCallable` object is called.
|
|
"""
|
|
_request: RequestType
|
|
_send_unary_request_task: asyncio.Task
|
|
|
|
# pylint: disable=too-many-arguments
|
|
def __init__(self, request: RequestType, deadline: Optional[float],
|
|
metadata: Metadata,
|
|
credentials: Optional[grpc.CallCredentials],
|
|
wait_for_ready: Optional[bool], channel: cygrpc.AioChannel,
|
|
method: bytes, request_serializer: SerializingFunction,
|
|
response_deserializer: DeserializingFunction,
|
|
loop: asyncio.AbstractEventLoop) -> None:
|
|
super().__init__(
|
|
channel.call(method, deadline, credentials, wait_for_ready),
|
|
metadata, request_serializer, response_deserializer, loop)
|
|
self._request = request
|
|
self._send_unary_request_task = loop.create_task(
|
|
self._send_unary_request())
|
|
self._init_stream_response_mixin(self._send_unary_request_task)
|
|
|
|
async def _send_unary_request(self) -> ResponseType:
|
|
serialized_request = _common.serialize(self._request,
|
|
self._request_serializer)
|
|
try:
|
|
await self._cython_call.initiate_unary_stream(
|
|
serialized_request, self._metadata)
|
|
except asyncio.CancelledError:
|
|
if not self.cancelled():
|
|
self.cancel()
|
|
raise
|
|
|
|
async def wait_for_connection(self) -> None:
|
|
await self._send_unary_request_task
|
|
if self.done():
|
|
await self._raise_for_status()
|
|
|
|
|
|
class StreamUnaryCall(_StreamRequestMixin, _UnaryResponseMixin, Call,
|
|
_base_call.StreamUnaryCall):
|
|
"""Object for managing stream-unary RPC calls.
|
|
|
|
Returned when an instance of `StreamUnaryMultiCallable` object is called.
|
|
"""
|
|
|
|
# pylint: disable=too-many-arguments
|
|
def __init__(self, request_iterator: Optional[RequestIterableType],
|
|
deadline: Optional[float], metadata: Metadata,
|
|
credentials: Optional[grpc.CallCredentials],
|
|
wait_for_ready: Optional[bool], channel: cygrpc.AioChannel,
|
|
method: bytes, request_serializer: SerializingFunction,
|
|
response_deserializer: DeserializingFunction,
|
|
loop: asyncio.AbstractEventLoop) -> None:
|
|
super().__init__(
|
|
channel.call(method, deadline, credentials, wait_for_ready),
|
|
metadata, request_serializer, response_deserializer, loop)
|
|
|
|
self._init_stream_request_mixin(request_iterator)
|
|
self._init_unary_response_mixin(loop.create_task(self._conduct_rpc()))
|
|
|
|
async def _conduct_rpc(self) -> ResponseType:
|
|
try:
|
|
serialized_response = await self._cython_call.stream_unary(
|
|
self._metadata, self._metadata_sent_observer)
|
|
except asyncio.CancelledError:
|
|
if not self.cancelled():
|
|
self.cancel()
|
|
raise
|
|
|
|
if self._cython_call.is_ok():
|
|
return _common.deserialize(serialized_response,
|
|
self._response_deserializer)
|
|
else:
|
|
return cygrpc.EOF
|
|
|
|
|
|
class StreamStreamCall(_StreamRequestMixin, _StreamResponseMixin, Call,
|
|
_base_call.StreamStreamCall):
|
|
"""Object for managing stream-stream RPC calls.
|
|
|
|
Returned when an instance of `StreamStreamMultiCallable` object is called.
|
|
"""
|
|
_initializer: asyncio.Task
|
|
|
|
# pylint: disable=too-many-arguments
|
|
def __init__(self, request_iterator: Optional[RequestIterableType],
|
|
deadline: Optional[float], metadata: Metadata,
|
|
credentials: Optional[grpc.CallCredentials],
|
|
wait_for_ready: Optional[bool], channel: cygrpc.AioChannel,
|
|
method: bytes, request_serializer: SerializingFunction,
|
|
response_deserializer: DeserializingFunction,
|
|
loop: asyncio.AbstractEventLoop) -> None:
|
|
super().__init__(
|
|
channel.call(method, deadline, credentials, wait_for_ready),
|
|
metadata, request_serializer, response_deserializer, loop)
|
|
self._initializer = self._loop.create_task(self._prepare_rpc())
|
|
self._init_stream_request_mixin(request_iterator)
|
|
self._init_stream_response_mixin(self._initializer)
|
|
|
|
async def _prepare_rpc(self):
|
|
"""This method prepares the RPC for receiving/sending messages.
|
|
|
|
All other operations around the stream should only happen after the
|
|
completion of this method.
|
|
"""
|
|
try:
|
|
await self._cython_call.initiate_stream_stream(
|
|
self._metadata, self._metadata_sent_observer)
|
|
except asyncio.CancelledError:
|
|
if not self.cancelled():
|
|
self.cancel()
|
|
# No need to raise RpcError here, because no one will `await` this task.
|