simple_on_shutdown

Convenient macro to specify on shutdown callbacks (e.g., for web server
runtimes) in a simple way. For example, this is useful in a tokio runtime to
execute things when the runtime is about to exit.

Usage

Recommended

use simple_on_shutdown::on_shutdown;

fn main() {
    // macro can take: direct expression
    on_shutdown!(println!("shut down with success"));
    // closure expression
    on_shutdown!(|| println!("shut down with success"));
    // move closure expression
    on_shutdown!(move || println!("shut down with success"));
    // block
    on_shutdown!({ println!("shut down with success") });
    // identifier
    let identifier = || println!("shut down with success");
    on_shutdown!(identifier);
}

Examples

See examples/-dir in repository!.

⚠ Restrictions ⚠

• There is no guarantee that this gets executed in "non-regular" shutdown scenarios, like
  CTRL+C / SIGINT / SIGTERM
• your application must handle SIGINT/SIGTERM (and other signals) properly to allow a gracefully "non-regular"
  shutdown (Actix web framework does this for example)
  • i.e. if you don't handle signals CTRL+C will immediately shut down your app
• Even in that case: there is no guarantee in every case that the operating system gives your application more time
  after it has been (forcefully) killed
• this behaviour differs a little between Windows and UNIX. See example/src/bin/simple_example_ctrl_c_signal for
  more details.