Caching auth between users about goose

[jeremyandrews]

To only log each user in once, you'd use set_on_start() and the GooseUser will log in and then make all subsequent requests as an authenticated user:
https://docs.rs/goose/latest/goose/goose/struct.Transaction.html#method.set_on_start

To truly only log in once, you could instead call test_start():
https://docs.rs/goose/latest/goose/struct.GooseAttack.html#method.test_start

However, you'd then be responsible for saving whatever session information is needed, most likely requiring that you build each user setting the appropriate header or cookie etc:
https://docs.rs/goose/latest/goose/goose/struct.GooseUser.html#method.set_client_builder

[buck06191]

That's really helpful. What's the idiomatic way to pass session information from that global level down into a GooseUser? The user created for the test_start method wouldn't have its information saved and I can't see a way to get information out of that thread and back up to the main function to be passed down to future users?

[jeremyandrews]

When I did something similar for a client some time ago, I used OnceCell. I essentially populated it during test_start() which runs before the GooseUser's are created for the load test, and then used it in set_on_start() to simulate per GooseUser login.

[buck06191]

Grand. Thank you. I ended up leaning into std::sync::OnceLock. I'll share a very basic snippet of it here for anyone else that comes across this

// globals.rs 
pub static SESSION: OnceLock<Box<Session>> = OnceLock::new();

pub fn build_global_session(
    auth_token: SecretString,
    api_key: SecretString,
) {
    let session = Session {
        auth_token,
        api_key,
    };
    let boxed_session = Box::new(session);

    SESSION.get_or_init(|| boxed_session);
}

// authorisation.rs
pub async fn setup_custom_client(user: &mut GooseUser) -> TransactionResult {
    let session = SESSION.get().expect("Couldn't get the global session data");
    user.set_session_data(session);

    Ok(())
}

Thanks for your help!

[jeremyandrews]

Great! If you'd like to make a quick PR, it would be great to add another example that demonstrates this:
https://github.com/tag1consulting/goose/tree/main/examples