Added delete option to database storage.

venv/Lib/site-packages/grpc/aio/_channel.py

@@ -0,0 +1,469 @@
+# Copyright 2019 gRPC authors.
+#
+# 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.
+"""Invocation-side implementation of gRPC Asyncio Python."""
+
+import asyncio
+import sys
+from typing import Any, Iterable, Optional, Sequence, List
+
+import grpc
+from grpc import _common, _compression, _grpcio_metadata
+from grpc._cython import cygrpc
+
+from . import _base_call, _base_channel
+from ._call import (StreamStreamCall, StreamUnaryCall, UnaryStreamCall,
+                    UnaryUnaryCall)
+from ._interceptor import (
+    InterceptedUnaryUnaryCall, InterceptedUnaryStreamCall,
+    InterceptedStreamUnaryCall, InterceptedStreamStreamCall, ClientInterceptor,
+    UnaryUnaryClientInterceptor, UnaryStreamClientInterceptor,
+    StreamUnaryClientInterceptor, StreamStreamClientInterceptor)
+from ._metadata import Metadata
+from ._typing import (ChannelArgumentType, DeserializingFunction,
+                      SerializingFunction, RequestIterableType)
+from ._utils import _timeout_to_deadline
+
+_USER_AGENT = 'grpc-python-asyncio/{}'.format(_grpcio_metadata.__version__)
+
+if sys.version_info[1] < 7:
+
+    def _all_tasks() -> Iterable[asyncio.Task]:
+        return asyncio.Task.all_tasks()
+else:
+
+    def _all_tasks() -> Iterable[asyncio.Task]:
+        return asyncio.all_tasks()
+
+
+def _augment_channel_arguments(base_options: ChannelArgumentType,
+                               compression: Optional[grpc.Compression]):
+    compression_channel_argument = _compression.create_channel_option(
+        compression)
+    user_agent_channel_argument = ((
+        cygrpc.ChannelArgKey.primary_user_agent_string,
+        _USER_AGENT,
+    ),)
+    return tuple(base_options
+                ) + compression_channel_argument + user_agent_channel_argument
+
+
+class _BaseMultiCallable:
+    """Base class of all multi callable objects.
+
+    Handles the initialization logic and stores common attributes.
+    """
+    _loop: asyncio.AbstractEventLoop
+    _channel: cygrpc.AioChannel
+    _method: bytes
+    _request_serializer: SerializingFunction
+    _response_deserializer: DeserializingFunction
+    _interceptors: Optional[Sequence[ClientInterceptor]]
+    _loop: asyncio.AbstractEventLoop
+
+    # pylint: disable=too-many-arguments
+    def __init__(
+            self,
+            channel: cygrpc.AioChannel,
+            method: bytes,
+            request_serializer: SerializingFunction,
+            response_deserializer: DeserializingFunction,
+            interceptors: Optional[Sequence[ClientInterceptor]],
+            loop: asyncio.AbstractEventLoop,
+    ) -> None:
+        self._loop = loop
+        self._channel = channel
+        self._method = method
+        self._request_serializer = request_serializer
+        self._response_deserializer = response_deserializer
+        self._interceptors = interceptors
+
+    @staticmethod
+    def _init_metadata(metadata: Optional[Metadata] = None,
+                       compression: Optional[grpc.Compression] = None
+                      ) -> Metadata:
+        """Based on the provided values for <metadata> or <compression> initialise the final
+        metadata, as it should be used for the current call.
+        """
+        metadata = metadata or Metadata()
+        if compression:
+            metadata = Metadata(
+                *_compression.augment_metadata(metadata, compression))
+        return metadata
+
+
+class UnaryUnaryMultiCallable(_BaseMultiCallable,
+                              _base_channel.UnaryUnaryMultiCallable):
+
+    def __call__(self,
+                 request: Any,
+                 *,
+                 timeout: Optional[float] = None,
+                 metadata: Optional[Metadata] = None,
+                 credentials: Optional[grpc.CallCredentials] = None,
+                 wait_for_ready: Optional[bool] = None,
+                 compression: Optional[grpc.Compression] = None
+                ) -> _base_call.UnaryUnaryCall:
+
+        metadata = self._init_metadata(metadata, compression)
+        if not self._interceptors:
+            call = UnaryUnaryCall(request, _timeout_to_deadline(timeout),
+                                  metadata, credentials, wait_for_ready,
+                                  self._channel, self._method,
+                                  self._request_serializer,
+                                  self._response_deserializer, self._loop)
+        else:
+            call = InterceptedUnaryUnaryCall(
+                self._interceptors, request, timeout, metadata, credentials,
+                wait_for_ready, self._channel, self._method,
+                self._request_serializer, self._response_deserializer,
+                self._loop)
+
+        return call
+
+
+class UnaryStreamMultiCallable(_BaseMultiCallable,
+                               _base_channel.UnaryStreamMultiCallable):
+
+    def __call__(self,
+                 request: Any,
+                 *,
+                 timeout: Optional[float] = None,
+                 metadata: Optional[Metadata] = None,
+                 credentials: Optional[grpc.CallCredentials] = None,
+                 wait_for_ready: Optional[bool] = None,
+                 compression: Optional[grpc.Compression] = None
+                ) -> _base_call.UnaryStreamCall:
+
+        metadata = self._init_metadata(metadata, compression)
+        deadline = _timeout_to_deadline(timeout)
+
+        if not self._interceptors:
+            call = UnaryStreamCall(request, deadline, metadata, credentials,
+                                   wait_for_ready, self._channel, self._method,
+                                   self._request_serializer,
+                                   self._response_deserializer, self._loop)
+        else:
+            call = InterceptedUnaryStreamCall(
+                self._interceptors, request, deadline, metadata, credentials,
+                wait_for_ready, self._channel, self._method,
+                self._request_serializer, self._response_deserializer,
+                self._loop)
+
+        return call
+
+
+class StreamUnaryMultiCallable(_BaseMultiCallable,
+                               _base_channel.StreamUnaryMultiCallable):
+
+    def __call__(self,
+                 request_iterator: Optional[RequestIterableType] = None,
+                 timeout: Optional[float] = None,
+                 metadata: Optional[Metadata] = None,
+                 credentials: Optional[grpc.CallCredentials] = None,
+                 wait_for_ready: Optional[bool] = None,
+                 compression: Optional[grpc.Compression] = None
+                ) -> _base_call.StreamUnaryCall:
+
+        metadata = self._init_metadata(metadata, compression)
+        deadline = _timeout_to_deadline(timeout)
+
+        if not self._interceptors:
+            call = StreamUnaryCall(request_iterator, deadline, metadata,
+                                   credentials, wait_for_ready, self._channel,
+                                   self._method, self._request_serializer,
+                                   self._response_deserializer, self._loop)
+        else:
+            call = InterceptedStreamUnaryCall(
+                self._interceptors, request_iterator, deadline, metadata,
+                credentials, wait_for_ready, self._channel, self._method,
+                self._request_serializer, self._response_deserializer,
+                self._loop)
+
+        return call
+
+
+class StreamStreamMultiCallable(_BaseMultiCallable,
+                                _base_channel.StreamStreamMultiCallable):
+
+    def __call__(self,
+                 request_iterator: Optional[RequestIterableType] = None,
+                 timeout: Optional[float] = None,
+                 metadata: Optional[Metadata] = None,
+                 credentials: Optional[grpc.CallCredentials] = None,
+                 wait_for_ready: Optional[bool] = None,
+                 compression: Optional[grpc.Compression] = None
+                ) -> _base_call.StreamStreamCall:
+
+        metadata = self._init_metadata(metadata, compression)
+        deadline = _timeout_to_deadline(timeout)
+
+        if not self._interceptors:
+            call = StreamStreamCall(request_iterator, deadline, metadata,
+                                    credentials, wait_for_ready, self._channel,
+                                    self._method, self._request_serializer,
+                                    self._response_deserializer, self._loop)
+        else:
+            call = InterceptedStreamStreamCall(
+                self._interceptors, request_iterator, deadline, metadata,
+                credentials, wait_for_ready, self._channel, self._method,
+                self._request_serializer, self._response_deserializer,
+                self._loop)
+
+        return call
+
+
+class Channel(_base_channel.Channel):
+    _loop: asyncio.AbstractEventLoop
+    _channel: cygrpc.AioChannel
+    _unary_unary_interceptors: List[UnaryUnaryClientInterceptor]
+    _unary_stream_interceptors: List[UnaryStreamClientInterceptor]
+    _stream_unary_interceptors: List[StreamUnaryClientInterceptor]
+    _stream_stream_interceptors: List[StreamStreamClientInterceptor]
+
+    def __init__(self, target: str, options: ChannelArgumentType,
+                 credentials: Optional[grpc.ChannelCredentials],
+                 compression: Optional[grpc.Compression],
+                 interceptors: Optional[Sequence[ClientInterceptor]]):
+        """Constructor.
+
+        Args:
+          target: The target to which to connect.
+          options: Configuration options for the channel.
+          credentials: A cygrpc.ChannelCredentials or None.
+          compression: An optional value indicating the compression method to be
+            used over the lifetime of the channel.
+          interceptors: An optional list of interceptors that would be used for
+            intercepting any RPC executed with that channel.
+        """
+        self._unary_unary_interceptors = []
+        self._unary_stream_interceptors = []
+        self._stream_unary_interceptors = []
+        self._stream_stream_interceptors = []
+
+        if interceptors is not None:
+            for interceptor in interceptors:
+                if isinstance(interceptor, UnaryUnaryClientInterceptor):
+                    self._unary_unary_interceptors.append(interceptor)
+                elif isinstance(interceptor, UnaryStreamClientInterceptor):
+                    self._unary_stream_interceptors.append(interceptor)
+                elif isinstance(interceptor, StreamUnaryClientInterceptor):
+                    self._stream_unary_interceptors.append(interceptor)
+                elif isinstance(interceptor, StreamStreamClientInterceptor):
+                    self._stream_stream_interceptors.append(interceptor)
+                else:
+                    raise ValueError(
+                        "Interceptor {} must be ".format(interceptor) +
+                        "{} or ".format(UnaryUnaryClientInterceptor.__name__) +
+                        "{} or ".format(UnaryStreamClientInterceptor.__name__) +
+                        "{} or ".format(StreamUnaryClientInterceptor.__name__) +
+                        "{}. ".format(StreamStreamClientInterceptor.__name__))
+
+        self._loop = cygrpc.get_working_loop()
+        self._channel = cygrpc.AioChannel(
+            _common.encode(target),
+            _augment_channel_arguments(options, compression), credentials,
+            self._loop)
+
+    async def __aenter__(self):
+        return self
+
+    async def __aexit__(self, exc_type, exc_val, exc_tb):
+        await self._close(None)
+
+    async def _close(self, grace):  # pylint: disable=too-many-branches
+        if self._channel.closed():
+            return
+
+        # No new calls will be accepted by the Cython channel.
+        self._channel.closing()
+
+        # Iterate through running tasks
+        tasks = _all_tasks()
+        calls = []
+        call_tasks = []
+        for task in tasks:
+            try:
+                stack = task.get_stack(limit=1)
+            except AttributeError as attribute_error:
+                # NOTE(lidiz) tl;dr: If the Task is created with a CPython
+                # object, it will trigger AttributeError.
+                #
+                # In the global finalizer, the event loop schedules
+                # a CPython PyAsyncGenAThrow object.
+                # https://github.com/python/cpython/blob/00e45877e33d32bb61aa13a2033e3bba370bda4d/Lib/asyncio/base_events.py#L484
+                #
+                # However, the PyAsyncGenAThrow object is written in C and
+                # failed to include the normal Python frame objects. Hence,
+                # this exception is a false negative, and it is safe to ignore
+                # the failure. It is fixed by https://github.com/python/cpython/pull/18669,
+                # but not available until 3.9 or 3.8.3. So, we have to keep it
+                # for a while.
+                # TODO(lidiz) drop this hack after 3.8 deprecation
+                if 'frame' in str(attribute_error):
+                    continue
+                else:
+                    raise
+
+            # If the Task is created by a C-extension, the stack will be empty.
+            if not stack:
+                continue
+
+            # Locate ones created by `aio.Call`.
+            frame = stack[0]
+            candidate = frame.f_locals.get('self')
+            if candidate:
+                if isinstance(candidate, _base_call.Call):
+                    if hasattr(candidate, '_channel'):
+                        # For intercepted Call object
+                        if candidate._channel is not self._channel:
+                            continue
+                    elif hasattr(candidate, '_cython_call'):
+                        # For normal Call object
+                        if candidate._cython_call._channel is not self._channel:
+                            continue
+                    else:
+                        # Unidentified Call object
+                        raise cygrpc.InternalError(
+                            f'Unrecognized call object: {candidate}')
+
+                    calls.append(candidate)
+                    call_tasks.append(task)
+
+        # If needed, try to wait for them to finish.
+        # Call objects are not always awaitables.
+        if grace and call_tasks:
+            await asyncio.wait(call_tasks, timeout=grace, loop=self._loop)
+
+        # Time to cancel existing calls.
+        for call in calls:
+            call.cancel()
+
+        # Destroy the channel
+        self._channel.close()
+
+    async def close(self, grace: Optional[float] = None):
+        await self._close(grace)
+
+    def get_state(self,
+                  try_to_connect: bool = False) -> grpc.ChannelConnectivity:
+        result = self._channel.check_connectivity_state(try_to_connect)
+        return _common.CYGRPC_CONNECTIVITY_STATE_TO_CHANNEL_CONNECTIVITY[result]
+
+    async def wait_for_state_change(
+            self,
+            last_observed_state: grpc.ChannelConnectivity,
+    ) -> None:
+        assert await self._channel.watch_connectivity_state(
+            last_observed_state.value[0], None)
+
+    async def channel_ready(self) -> None:
+        state = self.get_state(try_to_connect=True)
+        while state != grpc.ChannelConnectivity.READY:
+            await self.wait_for_state_change(state)
+            state = self.get_state(try_to_connect=True)
+
+    def unary_unary(
+            self,
+            method: str,
+            request_serializer: Optional[SerializingFunction] = None,
+            response_deserializer: Optional[DeserializingFunction] = None
+    ) -> UnaryUnaryMultiCallable:
+        return UnaryUnaryMultiCallable(self._channel, _common.encode(method),
+                                       request_serializer,
+                                       response_deserializer,
+                                       self._unary_unary_interceptors,
+                                       self._loop)
+
+    def unary_stream(
+            self,
+            method: str,
+            request_serializer: Optional[SerializingFunction] = None,
+            response_deserializer: Optional[DeserializingFunction] = None
+    ) -> UnaryStreamMultiCallable:
+        return UnaryStreamMultiCallable(self._channel, _common.encode(method),
+                                        request_serializer,
+                                        response_deserializer,
+                                        self._unary_stream_interceptors,
+                                        self._loop)
+
+    def stream_unary(
+            self,
+            method: str,
+            request_serializer: Optional[SerializingFunction] = None,
+            response_deserializer: Optional[DeserializingFunction] = None
+    ) -> StreamUnaryMultiCallable:
+        return StreamUnaryMultiCallable(self._channel, _common.encode(method),
+                                        request_serializer,
+                                        response_deserializer,
+                                        self._stream_unary_interceptors,
+                                        self._loop)
+
+    def stream_stream(
+            self,
+            method: str,
+            request_serializer: Optional[SerializingFunction] = None,
+            response_deserializer: Optional[DeserializingFunction] = None
+    ) -> StreamStreamMultiCallable:
+        return StreamStreamMultiCallable(self._channel, _common.encode(method),
+                                         request_serializer,
+                                         response_deserializer,
+                                         self._stream_stream_interceptors,
+                                         self._loop)
+
+
+def insecure_channel(
+        target: str,
+        options: Optional[ChannelArgumentType] = None,
+        compression: Optional[grpc.Compression] = None,
+        interceptors: Optional[Sequence[ClientInterceptor]] = None):
+    """Creates an insecure asynchronous Channel to a server.
+
+    Args:
+      target: The server address
+      options: An optional list of key-value pairs (:term:`channel_arguments`
+        in gRPC Core runtime) to configure the channel.
+      compression: An optional value indicating the compression method to be
+        used over the lifetime of the channel. This is an EXPERIMENTAL option.
+      interceptors: An optional sequence of interceptors that will be executed for
+        any call executed with this channel.
+
+    Returns:
+      A Channel.
+    """
+    return Channel(target, () if options is None else options, None,
+                   compression, interceptors)
+
+
+def secure_channel(target: str,
+                   credentials: grpc.ChannelCredentials,
+                   options: Optional[ChannelArgumentType] = None,
+                   compression: Optional[grpc.Compression] = None,
+                   interceptors: Optional[Sequence[ClientInterceptor]] = None):
+    """Creates a secure asynchronous Channel to a server.
+
+    Args:
+      target: The server address.
+      credentials: A ChannelCredentials instance.
+      options: An optional list of key-value pairs (:term:`channel_arguments`
+        in gRPC Core runtime) to configure the channel.
+      compression: An optional value indicating the compression method to be
+        used over the lifetime of the channel. This is an EXPERIMENTAL option.
+      interceptors: An optional sequence of interceptors that will be executed for
+        any call executed with this channel.
+
+    Returns:
+      An aio.Channel.
+    """
+    return Channel(target, () if options is None else options,
+                   credentials._credentials, compression, interceptors)