Re: [tarantool-patches] [PATCH v3 1/3] box: get rid of atexit() for calling cleanup routine

[Vladimir Davydov <vdavydov.dev@gmail.com>]

On Tue, Dec 11, 2018 at 04:24:38PM +0300, Serge Petrenko wrote:
> Move a call to tarantool_free() to the end of main().
> Also instead of breaking the event loop directly when processing a
> signal start a fiber which can do some work before event loop break and
> then break the event loop (this will be helpful when on_shutdown
> triggers are implemented to run them while ev loop active).
> Only wal_thread_stop() is left in atexit() to make sure we close the
> journal in case the user exits by typing os.exit() to the console.

I don't understand why you need to do it in the scope of the issue
you're intending to fix. You can start a fiber from SITERM/SIGINT signal
handler and run on_shutdown triggers from it without atexit rework,
right?

> @@ -119,11 +120,33 @@ sig_checkpoint(ev_loop * /* loop */, struct ev_signal * /* w */,
>  	fiber_wakeup(f);
>  }
>  
> +static int
> +on_exit_f(va_list ap)
> +{
> +	(void) ap;
> +	/* Terminate the main event loop. */
> +	ev_break(loop(), EVBREAK_ALL);
> +	return 0;
> +}
> +
> +void
> +tarantool_exit(void)
> +{
> +	struct fiber *f = fiber_new("on_shutdown", on_exit_f);
> +	if (f == NULL) {
> +		say_warn("failed to allocate a fiber to run shutdown routines.");
> +		ev_break(loop(), EVBREAK_ALL);
> +		return;
> +	}
> +	fiber_wakeup(f);

This should be done by the patch that introduces on_shutdown triggers,
otherwise it's unclear why you need a fiber here.

> +}
> +
>  static void
>  signal_cb(ev_loop *loop, struct ev_signal *w, int revents)
>  {
>  	(void) w;
>  	(void) revents;
> +	(void) loop;
>  
>  	/**
>  	 * If running in daemon mode, complain about possibly
> @@ -135,8 +158,8 @@ signal_cb(ev_loop *loop, struct ev_signal *w, int revents)
>  	if (pid_file)
>  		say_crit("got signal %d - %s", w->signum, strsignal(w->signum));
>  	start_loop = false;
> -	/* Terminate the main event loop */
> -	ev_break(loop, EVBREAK_ALL);
> +
> +	tarantool_exit();
>  }