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# 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.
from __future__ import annotations
import contextlib
import logging
import os
import random
import signal
import sys
import threading
import typing
from cotyledon import _service
from cotyledon import _utils
from cotyledon import types as t
if typing.TYPE_CHECKING:
import multiprocessing.connection
LOG = logging.getLogger(__name__)
MultiprocessingPipe: typing.TypeAlias = tuple[
"multiprocessing.connection.Connection",
"multiprocessing.connection.Connection",
]
OnNewWorkerHook: typing.TypeAlias = typing.Callable[
[t.ServiceId, t.WorkerId, _service.Service],
None,
]
P = typing.ParamSpec("P")
R = typing.TypeVar("R")
ServiceT = typing.TypeVar("ServiceT", bound=_service.Service)
class ServiceConfig(typing.Generic[ServiceT, P]):
def __init__(
self,
service_id: t.ServiceId,
service: type[ServiceT],
workers: int,
args: typing.Any, # noqa: ANN401
kwargs: typing.Any, # noqa: ANN401
) -> None:
self.service = service
self.workers = workers
self.args = () if args is None else args
self.kwargs = {} if kwargs is None else kwargs
self.service_id = service_id
def build(self, worker_id: t.WorkerId) -> ServiceT:
return self.service(worker_id, *self.args, **self.kwargs)
class ServiceWorker(_utils.SignalManager):
"""Service Worker Wrapper
This represents the child process spawned by ServiceManager
All methods implemented here, must run in the main threads
"""
@classmethod
def create_and_wait( # noqa: PLR0913,PLR0917
cls,
started_event: multiprocessing.synchronize.Event,
config: ServiceConfig[typing.Any, typing.Any],
service_id: t.ServiceId,
worker_id: t.WorkerId,
parent_pipe: MultiprocessingPipe,
started_hooks: list[OnNewWorkerHook],
graceful_shutdown_timeout: int,
) -> None:
sw = cls(
config,
service_id,
worker_id,
parent_pipe,
started_hooks,
graceful_shutdown_timeout,
)
started_event.set()
sw.wait_forever()
def __init__( # noqa: PLR0917, PLR0913
self,
config: ServiceConfig[typing.Any, typing.Any],
service_id: t.ServiceId,
worker_id: t.WorkerId,
parent_pipe: MultiprocessingPipe,
started_hooks: list[OnNewWorkerHook],
graceful_shutdown_timeout: int,
) -> None:
super().__init__()
self._ready = threading.Event()
self._signal_lock = threading.Lock()
_utils.spawn(self._watch_parent_process, parent_pipe)
# Reseed random number generator
random.seed()
self.service: _service.Service = config.build(worker_id)
# Backward compat: Just in case the __init__ is not called on the service
self.service.worker_id = worker_id
self.title = f"{self.service.name}({worker_id}) [{os.getpid()}]"
self._graceful_shutdown_timeout = graceful_shutdown_timeout
# Set process title
_utils.set_process_title(
f"{_utils.get_process_name()}: {self.service.name} worker({worker_id})",
)
# We are ready tell them
self._ready.set()
_utils.run_hooks(
"new_worker",
started_hooks,
service_id,
worker_id,
self.service,
)
def _get_graceful_shutdown_timeout(self) -> int:
if self.service.graceful_shutdown_timeout is None:
return self._graceful_shutdown_timeout
return self.service.graceful_shutdown_timeout
def _watch_parent_process(self, parent_pipe: MultiprocessingPipe) -> None:
# This will block until the write end is closed when the parent
# dies unexpectedly
parent_pipe[1].close()
with contextlib.suppress(EOFError):
parent_pipe[0].recv()
if self._ready.is_set():
LOG.info("Parent process has died unexpectedly, %s exiting", self.title)
if os.name == "posix":
os.kill(os.getpid(), signal.SIGTERM)
else:
# Fallback to process signal later
self._on_signal_received(signal.SIGTERM)
else:
os._exit(0)
def _alarm(self) -> None:
LOG.info(
"Graceful shutdown timeout (%d) exceeded, exiting %s now.",
self._get_graceful_shutdown_timeout(),
self.title,
)
os._exit(1)
def _fast_exit(self) -> None:
LOG.info(
"Caught SIGINT signal, instantaneous exiting of service %s",
self.title,
)
os._exit(1)
def _on_signal_received(self, sig: int) -> None:
# Code below must not block to return to select.select() and catch
# next signals
if sig == _utils.SIGALRM:
self._alarm()
if sig == signal.SIGINT:
self._fast_exit()
elif sig == signal.SIGTERM:
LOG.info(
"Caught SIGTERM signal, graceful exiting of service %s",
self.title,
)
timeout = self._get_graceful_shutdown_timeout()
if timeout > 0:
if os.name == "posix":
signal.alarm(timeout)
else:
threading.Timer(timeout, self._alarm).start()
_utils.spawn(self._service_terminate)
elif sig == _utils.SIGHUP:
_utils.spawn(self._service_reload)
def _service_run(self) -> None:
with _utils.exit_on_exception():
self.service.run()
def _service_terminate(self) -> None:
with _utils.exit_on_exception(), self._signal_lock:
self.service.terminate()
sys.exit(0)
def _service_reload(self) -> None:
with _utils.exit_on_exception():
if self._signal_lock.acquire(blocking=False):
try:
self.service.reload()
finally:
self._signal_lock.release()
def wait_forever(self) -> None:
LOG.debug("Run service %s", self.title)
_utils.spawn(self._service_run)
super()._wait_forever()
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