Tornado main loop

start_app.py

from tornado.web import AsyncIOMAinLoop
import asyncio

def make_application(
    handlers: Handlers = None,
    settings: str = "settings.py",
    command_line_parsing: bool = True,
    validation_function=None,
) -> tornado.web.Application:
    global ENABLE_PROFILER
    parse_options(
        settings, prefix="tda", command_line_enabled=command_line_parsing, validation_function=validation_function
    )
    ENABLE_PROFILER = bool(os.environ.get("ENABLE_PROFILER", False))
    ppx = options.path_prefix
    analytics.write_key = options.segment_project_token
    web_handlers = [
        (r"{}/".format(ppx), handlers.raml_handler),
        ....
        (
            r"{}/harness/?(.*)".format(ppx),
            tornado.web.StaticFileHandler,
            {"path": harness_root, "default_filename": "index.html"},
        ),
    ]
    app = tornado.web.Application(web_handlers, debug=options.debug, compress_response=options.compress_response)
    app.sentry_client = AsyncSentryClient(options.sentry_dsn)
    return app
  
def main_loop(name: str, handlers: Handlers, settings: str, validation_function=None):
    AsyncIOMainLoop().install()
    loop = asyncio.get_event_loop()
    try:
        app = make_application(handlers, settings, validation_function=validation_function)
    except ValidationError as error:
        logger.error(error)
        return

    port = options.port
    server = tornado.httpserver.HTTPServer(app)

    setup_translations()
    setup_logging()
    print_options()

    def signal_handler(*args):
        tornado.ioloop.IOLoop.instance().add_callback_from_signal(shutdown, server)

    signal.signal(signal.SIGTERM, signal_handler)  # catch standard kill
    signal.signal(signal.SIGINT, signal_handler)  # catch Ctrl+C
    server.listen(port)
    logger.info("TDA Driver %s: Listening on port::%d", name, port)
    loop.run_forever()