darkfi/doc/src/learn/dchat/deployment/writing-a-daemon.md

Writing a daemon

DarkFi consists of many seperate daemons communicating with each other. To run the p2p network, we'll need to implement our own daemon. So we'll start building dchat by configuring our main function into a daemon that can run the p2p network.

{{#include ../../../../../example/dchat/src/main.rs:daemon_deps}}

#[async_std::main]
async fn main() -> Result<()> {
    let ex = Arc::new(Executor::new());
    let ex2 = ex.clone();

    let nthreads = std::thread::available_parallelism().unwrap().get();
    let (signal, shutdown) = smol::channel::unbounded::<()>();

    let (_, result) = Parallel::new()
        .each(0..nthreads, |_| smol::future::block_on(ex2.run(shutdown.recv())))
        .finish(|| {
            smol::future::block_on(async move {
                drop(signal);
                Ok(())
            })
        });

    result

}

We get the number of cpu cores using std::thread::available_parallelism() and spin up a bunch of threads in parallel using easy_parallel. Right now it doesn't do anything, but soon we'll run dchat inside this block.

Note: DarkFi includes a macro called async_daemonize that is used by DarkFi binaries to minimize boilerplate in the repo. To keep things simple we will ignore this macro for the purpose of this tutorial. But check it out if you are curious: util/cli.rs.