150 lines
4.8 KiB
Python
150 lines
4.8 KiB
Python
# Copyright 2015 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.
|
|
"""Utilities for the gRPC Python Beta API."""
|
|
|
|
import threading
|
|
import time
|
|
|
|
# implementations is referenced from specification in this module.
|
|
from grpc.beta import implementations # pylint: disable=unused-import
|
|
from grpc.beta import interfaces
|
|
from grpc.framework.foundation import callable_util
|
|
from grpc.framework.foundation import future
|
|
|
|
_DONE_CALLBACK_EXCEPTION_LOG_MESSAGE = (
|
|
'Exception calling connectivity future "done" callback!')
|
|
|
|
|
|
class _ChannelReadyFuture(future.Future):
|
|
|
|
def __init__(self, channel):
|
|
self._condition = threading.Condition()
|
|
self._channel = channel
|
|
|
|
self._matured = False
|
|
self._cancelled = False
|
|
self._done_callbacks = []
|
|
|
|
def _block(self, timeout):
|
|
until = None if timeout is None else time.time() + timeout
|
|
with self._condition:
|
|
while True:
|
|
if self._cancelled:
|
|
raise future.CancelledError()
|
|
elif self._matured:
|
|
return
|
|
else:
|
|
if until is None:
|
|
self._condition.wait()
|
|
else:
|
|
remaining = until - time.time()
|
|
if remaining < 0:
|
|
raise future.TimeoutError()
|
|
else:
|
|
self._condition.wait(timeout=remaining)
|
|
|
|
def _update(self, connectivity):
|
|
with self._condition:
|
|
if (not self._cancelled and
|
|
connectivity is interfaces.ChannelConnectivity.READY):
|
|
self._matured = True
|
|
self._channel.unsubscribe(self._update)
|
|
self._condition.notify_all()
|
|
done_callbacks = tuple(self._done_callbacks)
|
|
self._done_callbacks = None
|
|
else:
|
|
return
|
|
|
|
for done_callback in done_callbacks:
|
|
callable_util.call_logging_exceptions(
|
|
done_callback, _DONE_CALLBACK_EXCEPTION_LOG_MESSAGE, self)
|
|
|
|
def cancel(self):
|
|
with self._condition:
|
|
if not self._matured:
|
|
self._cancelled = True
|
|
self._channel.unsubscribe(self._update)
|
|
self._condition.notify_all()
|
|
done_callbacks = tuple(self._done_callbacks)
|
|
self._done_callbacks = None
|
|
else:
|
|
return False
|
|
|
|
for done_callback in done_callbacks:
|
|
callable_util.call_logging_exceptions(
|
|
done_callback, _DONE_CALLBACK_EXCEPTION_LOG_MESSAGE, self)
|
|
|
|
return True
|
|
|
|
def cancelled(self):
|
|
with self._condition:
|
|
return self._cancelled
|
|
|
|
def running(self):
|
|
with self._condition:
|
|
return not self._cancelled and not self._matured
|
|
|
|
def done(self):
|
|
with self._condition:
|
|
return self._cancelled or self._matured
|
|
|
|
def result(self, timeout=None):
|
|
self._block(timeout)
|
|
return None
|
|
|
|
def exception(self, timeout=None):
|
|
self._block(timeout)
|
|
return None
|
|
|
|
def traceback(self, timeout=None):
|
|
self._block(timeout)
|
|
return None
|
|
|
|
def add_done_callback(self, fn):
|
|
with self._condition:
|
|
if not self._cancelled and not self._matured:
|
|
self._done_callbacks.append(fn)
|
|
return
|
|
|
|
fn(self)
|
|
|
|
def start(self):
|
|
with self._condition:
|
|
self._channel.subscribe(self._update, try_to_connect=True)
|
|
|
|
def __del__(self):
|
|
with self._condition:
|
|
if not self._cancelled and not self._matured:
|
|
self._channel.unsubscribe(self._update)
|
|
|
|
|
|
def channel_ready_future(channel):
|
|
"""Creates a future.Future tracking when an implementations.Channel is ready.
|
|
|
|
Cancelling the returned future.Future does not tell the given
|
|
implementations.Channel to abandon attempts it may have been making to
|
|
connect; cancelling merely deactivates the return future.Future's
|
|
subscription to the given implementations.Channel's connectivity.
|
|
|
|
Args:
|
|
channel: An implementations.Channel.
|
|
|
|
Returns:
|
|
A future.Future that matures when the given Channel has connectivity
|
|
interfaces.ChannelConnectivity.READY.
|
|
"""
|
|
ready_future = _ChannelReadyFuture(channel)
|
|
ready_future.start()
|
|
return ready_future
|