Source code for blackhole.supervisor

# -*- coding: utf-8 -*-

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"""Provides functionality to create the supervisor process."""


import asyncio
import logging
import os
import signal

from .config import Config
from .control import server
from .exceptions import BlackholeRuntimeException
from .utils import Singleton
from .worker import Worker


try:
    import setproctitle
except ImportError:
    setproctitle = None


__all__ = ("Supervisor",)
"""Tuple all the things."""


logger = logging.getLogger("blackhole.supervisor")


[docs]class Supervisor(metaclass=Singleton): """ The supervisor process. Responsible for monitoring and controlling child processes via an internal map of workers and the children they manage. """ def __init__(self, loop=None): """ Initialise the supervisor. Loads the configuration and event loop. :param loop: The event loop to use. :type loop: :py:class:`syncio.unix_events._UnixSelectorEventLoop` or :py:obj:`None` to get the current event loop using :py:func:`asyncio.get_event_loop`. :raises BlackholeRuntimeException: When an error occurs generating servers. """ logger.debug("Initiating the supervisor") self.config = Config() self.loop = loop if loop is not None else asyncio.get_event_loop() self.socks = [] self.workers = [] if setproctitle: setproctitle.setproctitle("blackhole: master") try: self.generate_servers() except BlackholeRuntimeException: self.close_socks() raise BlackholeRuntimeException()
[docs] def generate_servers(self): """Spawn all of the required sockets and TLS contexts.""" logger.debug("Attaching sockets to the supervisor") self.create_socket(self.config.listen) tls_conf = (self.config.tls_cert, self.config.tls_key) if len(self.config.tls_listen) > 0 and all(tls_conf): self.create_socket(self.config.tls_listen, use_tls=True)
[docs] def create_socket(self, listeners, use_tls=False): """Create supervisor socket.""" _tls = "" if use_tls: _tls = " (TLS)" for host, port, family, flags in listeners: aserver = server(host, port, family, use_tls=use_tls) self.socks.append(aserver) logger.debug(f"Attaching {host}:{port}{_tls} with flags {flags}")
[docs] def run(self): """ Start all workers and their children. Attaches signals and runs the event loop. """ self.start_workers() signal.signal(signal.SIGTERM, self.stop) signal.signal(signal.SIGINT, self.stop) self.loop.run_forever()
[docs] def start_workers(self): """Start each worker and it's child process.""" logger.debug("Starting workers") for idx in range(self.config.workers): num = f"{idx + 1}" logger.debug(f"Creating worker: {num}") self.workers.append(Worker(num, self.socks, self.loop))
[docs] def stop_workers(self): """Stop the workers and their respective child process.""" logger.debug("Stopping workers") worker_num = 1 for worker in self.workers: logger.debug(f"Stopping worker: {worker_num}") worker.stop() worker_num += 1
[docs] def close_socks(self): """Close all opened sockets.""" for sock in self.socks: sock["sock"].close()
[docs] def stop(self, *args, **kwargs): """ Terminate all of the workers. Generally should be called by a signal, nothing else. :raise SystemExit: With code :py:obj:`os.EX_OK`. """ self.stop_workers() self.close_socks() logger.debug("Stopping supervisor") try: self.loop.stop() except RuntimeError: pass raise SystemExit(os.EX_OK)