laywerrobot/lib/python3.6/site-packages/grpc/_server.py
2020-08-27 21:55:39 +02:00

838 lines
31 KiB
Python

# Copyright 2016 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.
"""Service-side implementation of gRPC Python."""
import collections
import enum
import logging
import threading
import time
import six
import grpc
from grpc import _common
from grpc import _interceptor
from grpc._cython import cygrpc
from grpc.framework.foundation import callable_util
_LOGGER = logging.getLogger(__name__)
_SHUTDOWN_TAG = 'shutdown'
_REQUEST_CALL_TAG = 'request_call'
_RECEIVE_CLOSE_ON_SERVER_TOKEN = 'receive_close_on_server'
_SEND_INITIAL_METADATA_TOKEN = 'send_initial_metadata'
_RECEIVE_MESSAGE_TOKEN = 'receive_message'
_SEND_MESSAGE_TOKEN = 'send_message'
_SEND_INITIAL_METADATA_AND_SEND_MESSAGE_TOKEN = (
'send_initial_metadata * send_message')
_SEND_STATUS_FROM_SERVER_TOKEN = 'send_status_from_server'
_SEND_INITIAL_METADATA_AND_SEND_STATUS_FROM_SERVER_TOKEN = (
'send_initial_metadata * send_status_from_server')
_OPEN = 'open'
_CLOSED = 'closed'
_CANCELLED = 'cancelled'
_EMPTY_FLAGS = 0
_UNEXPECTED_EXIT_SERVER_GRACE = 1.0
def _serialized_request(request_event):
return request_event.batch_operations[0].message()
def _application_code(code):
cygrpc_code = _common.STATUS_CODE_TO_CYGRPC_STATUS_CODE.get(code)
return cygrpc.StatusCode.unknown if cygrpc_code is None else cygrpc_code
def _completion_code(state):
if state.code is None:
return cygrpc.StatusCode.ok
else:
return _application_code(state.code)
def _abortion_code(state, code):
if state.code is None:
return code
else:
return _application_code(state.code)
def _details(state):
return b'' if state.details is None else state.details
class _HandlerCallDetails(
collections.namedtuple('_HandlerCallDetails', (
'method',
'invocation_metadata',
)), grpc.HandlerCallDetails):
pass
class _RPCState(object):
def __init__(self):
self.condition = threading.Condition()
self.due = set()
self.request = None
self.client = _OPEN
self.initial_metadata_allowed = True
self.disable_next_compression = False
self.trailing_metadata = None
self.code = None
self.details = None
self.statused = False
self.rpc_errors = []
self.callbacks = []
self.abortion = None
def _raise_rpc_error(state):
rpc_error = grpc.RpcError()
state.rpc_errors.append(rpc_error)
raise rpc_error
def _possibly_finish_call(state, token):
state.due.remove(token)
if (state.client is _CANCELLED or state.statused) and not state.due:
callbacks = state.callbacks
state.callbacks = None
return state, callbacks
else:
return None, ()
def _send_status_from_server(state, token):
def send_status_from_server(unused_send_status_from_server_event):
with state.condition:
return _possibly_finish_call(state, token)
return send_status_from_server
def _abort(state, call, code, details):
if state.client is not _CANCELLED:
effective_code = _abortion_code(state, code)
effective_details = details if state.details is None else state.details
if state.initial_metadata_allowed:
operations = (
cygrpc.SendInitialMetadataOperation(None, _EMPTY_FLAGS),
cygrpc.SendStatusFromServerOperation(
state.trailing_metadata, effective_code, effective_details,
_EMPTY_FLAGS),
)
token = _SEND_INITIAL_METADATA_AND_SEND_STATUS_FROM_SERVER_TOKEN
else:
operations = (cygrpc.SendStatusFromServerOperation(
state.trailing_metadata, effective_code, effective_details,
_EMPTY_FLAGS),)
token = _SEND_STATUS_FROM_SERVER_TOKEN
call.start_server_batch(operations,
_send_status_from_server(state, token))
state.statused = True
state.due.add(token)
def _receive_close_on_server(state):
def receive_close_on_server(receive_close_on_server_event):
with state.condition:
if receive_close_on_server_event.batch_operations[0].cancelled():
state.client = _CANCELLED
elif state.client is _OPEN:
state.client = _CLOSED
state.condition.notify_all()
return _possibly_finish_call(state, _RECEIVE_CLOSE_ON_SERVER_TOKEN)
return receive_close_on_server
def _receive_message(state, call, request_deserializer):
def receive_message(receive_message_event):
serialized_request = _serialized_request(receive_message_event)
if serialized_request is None:
with state.condition:
if state.client is _OPEN:
state.client = _CLOSED
state.condition.notify_all()
return _possibly_finish_call(state, _RECEIVE_MESSAGE_TOKEN)
else:
request = _common.deserialize(serialized_request,
request_deserializer)
with state.condition:
if request is None:
_abort(state, call, cygrpc.StatusCode.internal,
b'Exception deserializing request!')
else:
state.request = request
state.condition.notify_all()
return _possibly_finish_call(state, _RECEIVE_MESSAGE_TOKEN)
return receive_message
def _send_initial_metadata(state):
def send_initial_metadata(unused_send_initial_metadata_event):
with state.condition:
return _possibly_finish_call(state, _SEND_INITIAL_METADATA_TOKEN)
return send_initial_metadata
def _send_message(state, token):
def send_message(unused_send_message_event):
with state.condition:
state.condition.notify_all()
return _possibly_finish_call(state, token)
return send_message
class _Context(grpc.ServicerContext):
def __init__(self, rpc_event, state, request_deserializer):
self._rpc_event = rpc_event
self._state = state
self._request_deserializer = request_deserializer
def is_active(self):
with self._state.condition:
return self._state.client is not _CANCELLED and not self._state.statused
def time_remaining(self):
return max(self._rpc_event.call_details.deadline - time.time(), 0)
def cancel(self):
self._rpc_event.call.cancel()
def add_callback(self, callback):
with self._state.condition:
if self._state.callbacks is None:
return False
else:
self._state.callbacks.append(callback)
return True
def disable_next_message_compression(self):
with self._state.condition:
self._state.disable_next_compression = True
def invocation_metadata(self):
return self._rpc_event.invocation_metadata
def peer(self):
return _common.decode(self._rpc_event.call.peer())
def peer_identities(self):
return cygrpc.peer_identities(self._rpc_event.call)
def peer_identity_key(self):
id_key = cygrpc.peer_identity_key(self._rpc_event.call)
return id_key if id_key is None else _common.decode(id_key)
def auth_context(self):
return {
_common.decode(key): value
for key, value in six.iteritems(
cygrpc.auth_context(self._rpc_event.call))
}
def send_initial_metadata(self, initial_metadata):
with self._state.condition:
if self._state.client is _CANCELLED:
_raise_rpc_error(self._state)
else:
if self._state.initial_metadata_allowed:
operation = cygrpc.SendInitialMetadataOperation(
initial_metadata, _EMPTY_FLAGS)
self._rpc_event.call.start_server_batch(
(operation,), _send_initial_metadata(self._state))
self._state.initial_metadata_allowed = False
self._state.due.add(_SEND_INITIAL_METADATA_TOKEN)
else:
raise ValueError('Initial metadata no longer allowed!')
def set_trailing_metadata(self, trailing_metadata):
with self._state.condition:
self._state.trailing_metadata = trailing_metadata
def abort(self, code, details):
# treat OK like other invalid arguments: fail the RPC
if code == grpc.StatusCode.OK:
_LOGGER.error(
'abort() called with StatusCode.OK; returning UNKNOWN')
code = grpc.StatusCode.UNKNOWN
details = ''
with self._state.condition:
self._state.code = code
self._state.details = _common.encode(details)
self._state.abortion = Exception()
raise self._state.abortion
def set_code(self, code):
with self._state.condition:
self._state.code = code
def set_details(self, details):
with self._state.condition:
self._state.details = _common.encode(details)
class _RequestIterator(object):
def __init__(self, state, call, request_deserializer):
self._state = state
self._call = call
self._request_deserializer = request_deserializer
def _raise_or_start_receive_message(self):
if self._state.client is _CANCELLED:
_raise_rpc_error(self._state)
elif self._state.client is _CLOSED or self._state.statused:
raise StopIteration()
else:
self._call.start_server_batch(
(cygrpc.ReceiveMessageOperation(_EMPTY_FLAGS),),
_receive_message(self._state, self._call,
self._request_deserializer))
self._state.due.add(_RECEIVE_MESSAGE_TOKEN)
def _look_for_request(self):
if self._state.client is _CANCELLED:
_raise_rpc_error(self._state)
elif (self._state.request is None and
_RECEIVE_MESSAGE_TOKEN not in self._state.due):
raise StopIteration()
else:
request = self._state.request
self._state.request = None
return request
raise AssertionError() # should never run
def _next(self):
with self._state.condition:
self._raise_or_start_receive_message()
while True:
self._state.condition.wait()
request = self._look_for_request()
if request is not None:
return request
def __iter__(self):
return self
def __next__(self):
return self._next()
def next(self):
return self._next()
def _unary_request(rpc_event, state, request_deserializer):
def unary_request():
with state.condition:
if state.client is _CANCELLED or state.statused:
return None
else:
rpc_event.call.start_server_batch(
(cygrpc.ReceiveMessageOperation(_EMPTY_FLAGS),),
_receive_message(state, rpc_event.call,
request_deserializer))
state.due.add(_RECEIVE_MESSAGE_TOKEN)
while True:
state.condition.wait()
if state.request is None:
if state.client is _CLOSED:
details = '"{}" requires exactly one request message.'.format(
rpc_event.call_details.method)
_abort(state, rpc_event.call,
cygrpc.StatusCode.unimplemented,
_common.encode(details))
return None
elif state.client is _CANCELLED:
return None
else:
request = state.request
state.request = None
return request
return unary_request
def _call_behavior(rpc_event, state, behavior, argument, request_deserializer):
context = _Context(rpc_event, state, request_deserializer)
try:
return behavior(argument, context), True
except Exception as exception: # pylint: disable=broad-except
with state.condition:
if exception is state.abortion:
_abort(state, rpc_event.call, cygrpc.StatusCode.unknown,
b'RPC Aborted')
elif exception not in state.rpc_errors:
details = 'Exception calling application: {}'.format(exception)
_LOGGER.exception(details)
_abort(state, rpc_event.call, cygrpc.StatusCode.unknown,
_common.encode(details))
return None, False
def _take_response_from_response_iterator(rpc_event, state, response_iterator):
try:
return next(response_iterator), True
except StopIteration:
return None, True
except Exception as exception: # pylint: disable=broad-except
with state.condition:
if exception is state.abortion:
_abort(state, rpc_event.call, cygrpc.StatusCode.unknown,
b'RPC Aborted')
elif exception not in state.rpc_errors:
details = 'Exception iterating responses: {}'.format(exception)
_LOGGER.exception(details)
_abort(state, rpc_event.call, cygrpc.StatusCode.unknown,
_common.encode(details))
return None, False
def _serialize_response(rpc_event, state, response, response_serializer):
serialized_response = _common.serialize(response, response_serializer)
if serialized_response is None:
with state.condition:
_abort(state, rpc_event.call, cygrpc.StatusCode.internal,
b'Failed to serialize response!')
return None
else:
return serialized_response
def _send_response(rpc_event, state, serialized_response):
with state.condition:
if state.client is _CANCELLED or state.statused:
return False
else:
if state.initial_metadata_allowed:
operations = (
cygrpc.SendInitialMetadataOperation(None, _EMPTY_FLAGS),
cygrpc.SendMessageOperation(serialized_response,
_EMPTY_FLAGS),
)
state.initial_metadata_allowed = False
token = _SEND_INITIAL_METADATA_AND_SEND_MESSAGE_TOKEN
else:
operations = (cygrpc.SendMessageOperation(
serialized_response, _EMPTY_FLAGS),)
token = _SEND_MESSAGE_TOKEN
rpc_event.call.start_server_batch(operations,
_send_message(state, token))
state.due.add(token)
while True:
state.condition.wait()
if token not in state.due:
return state.client is not _CANCELLED and not state.statused
def _status(rpc_event, state, serialized_response):
with state.condition:
if state.client is not _CANCELLED:
code = _completion_code(state)
details = _details(state)
operations = [
cygrpc.SendStatusFromServerOperation(
state.trailing_metadata, code, details, _EMPTY_FLAGS),
]
if state.initial_metadata_allowed:
operations.append(
cygrpc.SendInitialMetadataOperation(None, _EMPTY_FLAGS))
if serialized_response is not None:
operations.append(
cygrpc.SendMessageOperation(serialized_response,
_EMPTY_FLAGS))
rpc_event.call.start_server_batch(
operations,
_send_status_from_server(state, _SEND_STATUS_FROM_SERVER_TOKEN))
state.statused = True
state.due.add(_SEND_STATUS_FROM_SERVER_TOKEN)
def _unary_response_in_pool(rpc_event, state, behavior, argument_thunk,
request_deserializer, response_serializer):
argument = argument_thunk()
if argument is not None:
response, proceed = _call_behavior(rpc_event, state, behavior, argument,
request_deserializer)
if proceed:
serialized_response = _serialize_response(
rpc_event, state, response, response_serializer)
if serialized_response is not None:
_status(rpc_event, state, serialized_response)
def _stream_response_in_pool(rpc_event, state, behavior, argument_thunk,
request_deserializer, response_serializer):
argument = argument_thunk()
if argument is not None:
response_iterator, proceed = _call_behavior(
rpc_event, state, behavior, argument, request_deserializer)
if proceed:
while True:
response, proceed = _take_response_from_response_iterator(
rpc_event, state, response_iterator)
if proceed:
if response is None:
_status(rpc_event, state, None)
break
else:
serialized_response = _serialize_response(
rpc_event, state, response, response_serializer)
if serialized_response is not None:
proceed = _send_response(rpc_event, state,
serialized_response)
if not proceed:
break
else:
break
else:
break
def _handle_unary_unary(rpc_event, state, method_handler, thread_pool):
unary_request = _unary_request(rpc_event, state,
method_handler.request_deserializer)
return thread_pool.submit(_unary_response_in_pool, rpc_event, state,
method_handler.unary_unary, unary_request,
method_handler.request_deserializer,
method_handler.response_serializer)
def _handle_unary_stream(rpc_event, state, method_handler, thread_pool):
unary_request = _unary_request(rpc_event, state,
method_handler.request_deserializer)
return thread_pool.submit(_stream_response_in_pool, rpc_event, state,
method_handler.unary_stream, unary_request,
method_handler.request_deserializer,
method_handler.response_serializer)
def _handle_stream_unary(rpc_event, state, method_handler, thread_pool):
request_iterator = _RequestIterator(state, rpc_event.call,
method_handler.request_deserializer)
return thread_pool.submit(
_unary_response_in_pool, rpc_event, state, method_handler.stream_unary,
lambda: request_iterator, method_handler.request_deserializer,
method_handler.response_serializer)
def _handle_stream_stream(rpc_event, state, method_handler, thread_pool):
request_iterator = _RequestIterator(state, rpc_event.call,
method_handler.request_deserializer)
return thread_pool.submit(
_stream_response_in_pool, rpc_event, state,
method_handler.stream_stream, lambda: request_iterator,
method_handler.request_deserializer, method_handler.response_serializer)
def _find_method_handler(rpc_event, generic_handlers, interceptor_pipeline):
def query_handlers(handler_call_details):
for generic_handler in generic_handlers:
method_handler = generic_handler.service(handler_call_details)
if method_handler is not None:
return method_handler
return None
handler_call_details = _HandlerCallDetails(
_common.decode(rpc_event.call_details.method),
rpc_event.invocation_metadata)
if interceptor_pipeline is not None:
return interceptor_pipeline.execute(query_handlers,
handler_call_details)
else:
return query_handlers(handler_call_details)
def _reject_rpc(rpc_event, status, details):
operations = (
cygrpc.SendInitialMetadataOperation(None, _EMPTY_FLAGS),
cygrpc.ReceiveCloseOnServerOperation(_EMPTY_FLAGS),
cygrpc.SendStatusFromServerOperation(None, status, details,
_EMPTY_FLAGS),
)
rpc_state = _RPCState()
rpc_event.call.start_server_batch(operations,
lambda ignored_event: (rpc_state, (),))
return rpc_state
def _handle_with_method_handler(rpc_event, method_handler, thread_pool):
state = _RPCState()
with state.condition:
rpc_event.call.start_server_batch(
(cygrpc.ReceiveCloseOnServerOperation(_EMPTY_FLAGS),),
_receive_close_on_server(state))
state.due.add(_RECEIVE_CLOSE_ON_SERVER_TOKEN)
if method_handler.request_streaming:
if method_handler.response_streaming:
return state, _handle_stream_stream(rpc_event, state,
method_handler, thread_pool)
else:
return state, _handle_stream_unary(rpc_event, state,
method_handler, thread_pool)
else:
if method_handler.response_streaming:
return state, _handle_unary_stream(rpc_event, state,
method_handler, thread_pool)
else:
return state, _handle_unary_unary(rpc_event, state,
method_handler, thread_pool)
def _handle_call(rpc_event, generic_handlers, interceptor_pipeline, thread_pool,
concurrency_exceeded):
if not rpc_event.success:
return None, None
if rpc_event.call_details.method is not None:
try:
method_handler = _find_method_handler(rpc_event, generic_handlers,
interceptor_pipeline)
except Exception as exception: # pylint: disable=broad-except
details = 'Exception servicing handler: {}'.format(exception)
_LOGGER.exception(details)
return _reject_rpc(rpc_event, cygrpc.StatusCode.unknown,
b'Error in service handler!'), None
if method_handler is None:
return _reject_rpc(rpc_event, cygrpc.StatusCode.unimplemented,
b'Method not found!'), None
elif concurrency_exceeded:
return _reject_rpc(rpc_event, cygrpc.StatusCode.resource_exhausted,
b'Concurrent RPC limit exceeded!'), None
else:
return _handle_with_method_handler(rpc_event, method_handler,
thread_pool)
else:
return None, None
@enum.unique
class _ServerStage(enum.Enum):
STOPPED = 'stopped'
STARTED = 'started'
GRACE = 'grace'
class _ServerState(object):
# pylint: disable=too-many-arguments
def __init__(self, completion_queue, server, generic_handlers,
interceptor_pipeline, thread_pool, maximum_concurrent_rpcs):
self.lock = threading.RLock()
self.completion_queue = completion_queue
self.server = server
self.generic_handlers = list(generic_handlers)
self.interceptor_pipeline = interceptor_pipeline
self.thread_pool = thread_pool
self.stage = _ServerStage.STOPPED
self.shutdown_events = None
self.maximum_concurrent_rpcs = maximum_concurrent_rpcs
self.active_rpc_count = 0
# TODO(https://github.com/grpc/grpc/issues/6597): eliminate these fields.
self.rpc_states = set()
self.due = set()
def _add_generic_handlers(state, generic_handlers):
with state.lock:
state.generic_handlers.extend(generic_handlers)
def _add_insecure_port(state, address):
with state.lock:
return state.server.add_http2_port(address)
def _add_secure_port(state, address, server_credentials):
with state.lock:
return state.server.add_http2_port(address,
server_credentials._credentials)
def _request_call(state):
state.server.request_call(state.completion_queue, state.completion_queue,
_REQUEST_CALL_TAG)
state.due.add(_REQUEST_CALL_TAG)
# TODO(https://github.com/grpc/grpc/issues/6597): delete this function.
def _stop_serving(state):
if not state.rpc_states and not state.due:
for shutdown_event in state.shutdown_events:
shutdown_event.set()
state.stage = _ServerStage.STOPPED
return True
else:
return False
def _on_call_completed(state):
with state.lock:
state.active_rpc_count -= 1
def _serve(state):
while True:
event = state.completion_queue.poll()
if event.tag is _SHUTDOWN_TAG:
with state.lock:
state.due.remove(_SHUTDOWN_TAG)
if _stop_serving(state):
return
elif event.tag is _REQUEST_CALL_TAG:
with state.lock:
state.due.remove(_REQUEST_CALL_TAG)
concurrency_exceeded = (
state.maximum_concurrent_rpcs is not None and
state.active_rpc_count >= state.maximum_concurrent_rpcs)
rpc_state, rpc_future = _handle_call(
event, state.generic_handlers, state.interceptor_pipeline,
state.thread_pool, concurrency_exceeded)
if rpc_state is not None:
state.rpc_states.add(rpc_state)
if rpc_future is not None:
state.active_rpc_count += 1
rpc_future.add_done_callback(
lambda unused_future: _on_call_completed(state))
if state.stage is _ServerStage.STARTED:
_request_call(state)
elif _stop_serving(state):
return
else:
rpc_state, callbacks = event.tag(event)
for callback in callbacks:
callable_util.call_logging_exceptions(
callback, 'Exception calling callback!')
if rpc_state is not None:
with state.lock:
state.rpc_states.remove(rpc_state)
if _stop_serving(state):
return
# We want to force the deletion of the previous event
# ~before~ we poll again; if the event has a reference
# to a shutdown Call object, this can induce spinlock.
event = None
def _stop(state, grace):
with state.lock:
if state.stage is _ServerStage.STOPPED:
shutdown_event = threading.Event()
shutdown_event.set()
return shutdown_event
else:
if state.stage is _ServerStage.STARTED:
state.server.shutdown(state.completion_queue, _SHUTDOWN_TAG)
state.stage = _ServerStage.GRACE
state.shutdown_events = []
state.due.add(_SHUTDOWN_TAG)
shutdown_event = threading.Event()
state.shutdown_events.append(shutdown_event)
if grace is None:
state.server.cancel_all_calls()
else:
def cancel_all_calls_after_grace():
shutdown_event.wait(timeout=grace)
with state.lock:
state.server.cancel_all_calls()
thread = threading.Thread(target=cancel_all_calls_after_grace)
thread.start()
return shutdown_event
shutdown_event.wait()
return shutdown_event
def _start(state):
with state.lock:
if state.stage is not _ServerStage.STOPPED:
raise ValueError('Cannot start already-started server!')
state.server.start()
state.stage = _ServerStage.STARTED
_request_call(state)
thread = threading.Thread(target=_serve, args=(state,))
thread.daemon = True
thread.start()
def _validate_generic_rpc_handlers(generic_rpc_handlers):
for generic_rpc_handler in generic_rpc_handlers:
service_attribute = getattr(generic_rpc_handler, 'service', None)
if service_attribute is None:
raise AttributeError(
'"{}" must conform to grpc.GenericRpcHandler type but does '
'not have "service" method!'.format(generic_rpc_handler))
class _Server(grpc.Server):
# pylint: disable=too-many-arguments
def __init__(self, thread_pool, generic_handlers, interceptors, options,
maximum_concurrent_rpcs):
completion_queue = cygrpc.CompletionQueue()
server = cygrpc.Server(options)
server.register_completion_queue(completion_queue)
self._state = _ServerState(completion_queue, server, generic_handlers,
_interceptor.service_pipeline(interceptors),
thread_pool, maximum_concurrent_rpcs)
def add_generic_rpc_handlers(self, generic_rpc_handlers):
_validate_generic_rpc_handlers(generic_rpc_handlers)
_add_generic_handlers(self._state, generic_rpc_handlers)
def add_insecure_port(self, address):
return _add_insecure_port(self._state, _common.encode(address))
def add_secure_port(self, address, server_credentials):
return _add_secure_port(self._state, _common.encode(address),
server_credentials)
def start(self):
_start(self._state)
def stop(self, grace):
return _stop(self._state, grace)
def __del__(self):
_stop(self._state, None)
def create_server(thread_pool, generic_rpc_handlers, interceptors, options,
maximum_concurrent_rpcs):
_validate_generic_rpc_handlers(generic_rpc_handlers)
return _Server(thread_pool, generic_rpc_handlers, interceptors, options,
maximum_concurrent_rpcs)