Fix connection refused error from udp client test

[mickvandijke]

When running the udp integration tests, the udp client often returns a connection refused error.

[josecelano]

@WarmBeer I've had that error in the past, and sometimes the problem is the server is not ready to receive requests yet.

I fixed it for the API and HTTP tracker by using a channel. The server notifies back to the launcher when it's ready, and the launcher waits (blocking) until the server is ready.

I suppose we could implement something similar for the UPD tracker.

For the HTTP tracker:

/// # Panics
///
/// It would panic if the `config::HttpTracker` struct would contain an inappropriate values.
pub async fn start_job(config: &HttpTracker, tracker: Arc<tracker::Tracker>) -> JoinHandle<()> {
    let bind_addr = config
        .bind_address
        .parse::<SocketAddr>()
        .expect("HTTP tracker server bind_address invalid.");
    let ssl_enabled = config.ssl_enabled;
    let ssl_cert_path = config.ssl_cert_path.clone();
    let ssl_key_path = config.ssl_key_path.clone();

    let (tx, rx) = oneshot::channel::<ServerJobStarted>();

    // Run the HTTP tracker server
    let join_handle = tokio::spawn(async move {
        let http_tracker = Http::new(tracker);

        if !ssl_enabled {
            info!("Starting HTTP tracker server on: http://{}", bind_addr);

            let handle = http_tracker.start(bind_addr);

            tx.send(ServerJobStarted())
                .expect("HTTP tracker server should not be dropped");

            handle.await;

            info!("HTTP tracker server on http://{} stopped", bind_addr);
        } else if ssl_enabled && ssl_cert_path.is_some() && ssl_key_path.is_some() {
            info!("Starting HTTPS server on: https://{}", bind_addr);

            let handle = http_tracker.start_tls(bind_addr, ssl_cert_path.unwrap(), ssl_key_path.unwrap());

            tx.send(ServerJobStarted())
                .expect("HTTP tracker server should not be dropped");

            handle.await;

            info!("HTTP tracker server on https://{} stopped", bind_addr);
        } else {
            warn!(
                "Could not start HTTPS tracker server on: {}, missing SSL Cert or Key!",
                bind_addr
            );
        }
    });

    // Wait until the HTTPS tracker server job is running
    match rx.await {
        Ok(_msg) => info!("HTTP tracker server started"),
        Err(e) => panic!("HTTP tracker server was dropped: {e}"),
    }

    join_handle
}

For the API:

/// # Panics
///
/// It would panic if unable to send the  `ApiServerJobStarted` notice.
pub async fn start_job(config: &HttpApi, tracker: Arc<tracker::Tracker>) -> JoinHandle<()> {
    let bind_addr = config
        .bind_address
        .parse::<std::net::SocketAddr>()
        .expect("Tracker API bind_address invalid.");
    let ssl_enabled = config.ssl_enabled;
    let ssl_cert_path = config.ssl_cert_path.clone();
    let ssl_key_path = config.ssl_key_path.clone();

    let (tx, rx) = oneshot::channel::<ApiServerJobStarted>();

    // Run the API server
    let join_handle = tokio::spawn(async move {
        if !ssl_enabled {
            info!("Starting Torrust APIs server on: http://{}", bind_addr);

            let handle = server::start(bind_addr, &tracker);

            tx.send(ApiServerJobStarted()).expect("the API server should not be dropped");

            if let Ok(()) = handle.await {
                info!("Torrust APIs server on http://{} stopped", bind_addr);
            }
        } else if ssl_enabled && ssl_cert_path.is_some() && ssl_key_path.is_some() {
            info!("Starting Torrust APIs server on: https://{}", bind_addr);

            let ssl_config = RustlsConfig::from_pem_file(ssl_cert_path.unwrap(), ssl_key_path.unwrap())
                .await
                .unwrap();

            let handle = server::start_tls(bind_addr, ssl_config, &tracker);

            tx.send(ApiServerJobStarted()).expect("the API server should not be dropped");

            if let Ok(()) = handle.await {
                info!("Torrust APIs server on https://{} stopped", bind_addr);
            }
        }
    });

    // Wait until the APIs server job is running
    match rx.await {
        Ok(_msg) => info!("Torrust APIs server started"),
        Err(e) => panic!("the API server was dropped: {e}"),
    }

    join_handle
}

[josecelano]

This should be fixed when #156 is finished.