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# 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.
"""Internal utilities for gRPC Python."""
import collections
import logging
import threading
import time
import grpc
from grpc import _common
import six
_LOGGER = logging.getLogger(__name__)
_DONE_CALLBACK_EXCEPTION_LOG_MESSAGE = (
'Exception calling connectivity future "done" callback!')
class RpcMethodHandler(
collections.namedtuple('_RpcMethodHandler', (
'request_streaming',
'response_streaming',
'request_deserializer',
'response_serializer',
'unary_unary',
'unary_stream',
'stream_unary',
'stream_stream',
)), grpc.RpcMethodHandler):
pass
class DictionaryGenericHandler(grpc.ServiceRpcHandler):
def __init__(self, service, method_handlers):
self._name = service
self._method_handlers = {
_common.fully_qualified_method(service, method): method_handler
for method, method_handler in six.iteritems(method_handlers)
}
def service_name(self):
return self._name
def service(self, handler_call_details):
return self._method_handlers.get(handler_call_details.method)
class _ChannelReadyFuture(grpc.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 grpc.FutureCancelledError()
elif self._matured:
return
else:
if until is None:
self._condition.wait()
else:
remaining = until - time.time()
if remaining < 0:
raise grpc.FutureTimeoutError()
else:
self._condition.wait(timeout=remaining)
def _update(self, connectivity):
with self._condition:
if (not self._cancelled and
connectivity is grpc.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:
try:
done_callback(self)
except Exception: # pylint: disable=broad-except
_LOGGER.exception(_DONE_CALLBACK_EXCEPTION_LOG_MESSAGE)
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:
try:
done_callback(self)
except Exception: # pylint: disable=broad-except
_LOGGER.exception(_DONE_CALLBACK_EXCEPTION_LOG_MESSAGE)
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)
def exception(self, timeout=None):
self._block(timeout)
def traceback(self, timeout=None):
self._block(timeout)
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):
ready_future = _ChannelReadyFuture(channel)
ready_future.start()
return ready_future
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