Initializing Bastion

Initialize

Bastion needs to be initialized. You can initialize it with the default configuration or with a custom one. A custom configuration will allow you to override the Backtraces* system

Enabled by default, a custom configuration will allow you to override it and enable or disable the Backtraces.

• Default configuration

use bastion::prelude::*;

fn main() {
    Bastion::init();

    // Some stuff have to be written later... but not yet!
}

• Custom configuration, we are hidding the backtraces here, you can still use show_backtraces(); to enable it.

use bastion::prelude::*;

fn main() {
    let config = Config::new().hide_backtraces();
    Bastion::init_with(config);

    // Some stuff have to be written later... but not yet!
}

Start

After you initialize bastion you will have to start it by using Bastion::start();.

use bastion::prelude::*;

fn main() {
    Bastion::init();
    Bastion::start();

    // Some stuff have to be written later... but not yet!
}

Block

As with any application, there will be a point where you want it to stop. But this time might not occur in your main() function. This can happen anywhere in your code.

Bastion provide Bastion::block_until_stopped(). It will block the current thread until the system is stopped (either by calling Bastion::stop() or Bastion::kill()).

use bastion::prelude::*;

fn main() {
    Bastion::init();
    Bastion::start();

    // Some stuff have to be written later... but not yet!

    Bastion::block_until_stopped();
}

Stop

At this point you might want to stop the bastion. You can use Bastion::stop().

It will send a message to the whole system to tell it to gracefully stop each running children groups and supervisors.

use bastion::prelude::*;

fn main() {
    Bastion::init();
    Bastion::start();

    // Some stuff have to be written later... but not yet!

    Bastion::stop();
}

As we said in the Block section of this chapter you may want to stop the application anywhere in your code. Here we will stop our bastion after the execution of stop_me_now().

use bastion::prelude::*;

async fn stop_me_now(_ctx: BastionContext) -> Result<(), ()> {
    Bastion::stop();
    Ok(())
}

fn main() {
    Bastion::init();
    Bastion::start();

    Bastion::children(|children| children.with_exec(stop_me_now))
        .expect("Couldn't create the children group.");
}

As you may have noticed, we don't block_until_stopped(); because the children's with_exec task will complete immediately. There's nothing to wait for.

Kill

In some case, in unrecoverable cases, you may want to just kill the system and drop all processes in execution. Bastion::kill(); is made for it.

use bastion::prelude::*;

fn main() {
    Bastion::init();
    Bastion::start();

    // Some stuff have to be written later... but not yet!

    Bastion::kill();
}

*Backtraces: Appendix - Definition