leaked_thread.rs

use actix::prelude::*;
use actix_web::{middleware, web, App, HttpResponse, HttpServer};
use log::info;

use std::io;
use std::thread;
use std::time::Duration;

fn my_handler() -> HttpResponse {
    "Hello".into()
}

fn list_threads() -> Vec<String> {
    let pid = std::process::id();
    let tasks = std::fs::read_dir(format!("/proc/{}/task/", pid)).unwrap();
    tasks
        .filter_map(|entry| {
            if let Ok(entry) = entry {
                let path = entry.path();
                let pid = path.file_name().unwrap();
                if let Ok(name) = std::fs::read_to_string(path.join("comm")) {
                    Some(format!("{}:{}", pid.to_string_lossy(), name.trim()))
                } else {
                    None
                }
            } else {
                None
            }
        })
        .collect()
}

fn main() -> Result<(), io::Error> {
    std::env::set_var("RUST_LOG", "info");
    env_logger::init();

    info!(
        "sleeping 1 sec on system thread; threads: \n{}",
        list_threads().join("\n")
    );
    thread::sleep(Duration::from_secs(1));

    let sys = System::new("example");

    info!(
        "sleeping 1 sec on system thread; threads: \n{}",
        list_threads().join("\n")
    );
    thread::sleep(Duration::from_secs(1));

    info!("creating http; threads: \n{}", list_threads().join("\n"));

    HttpServer::new(move || {
        App::new()
            .wrap(middleware::Logger::default())
            .service(web::resource("/").to(my_handler))
    })
    .workers(1)
    .disable_signals()
    .bind("127.0.0.1:8080")
    .unwrap()
    .start();

    info!(
        "sleeping 1 sec on system thread; threads: \n{}",
        list_threads().join("\n")
    );
    thread::sleep(Duration::from_secs(1));

    info!("creating stopper; threads: \n{}", list_threads().join("\n"));

    let _ = thread::Builder::new().name("stopper".to_string()).spawn({
        let sys = System::current();
        move || {
            for i in (1..=5).rev() {
                info!(
                    "will stop server and system in {}; threads: \n{}",
                    i,
                    list_threads().join("\n")
                );
                thread::sleep(Duration::from_secs(1));
            }

            info!(
                "sleeping 1 sec on stopper thread; threads: \n{}",
                list_threads().join("\n")
            );
            thread::sleep(Duration::from_secs(1));

            info!(
                "stopping system {}; threads: \n{}",
                sys.id(),
                list_threads().join("\n")
            );
            sys.stop();
        }
    });

    sys.run().unwrap();

    info!("system stopped; threads: \n{}", list_threads().join("\n"));
    for i in (1..=5).rev() {
        info!(
            "will stop in {}; threads: \n{}",
            i,
            list_threads().join("\n")
        );
        thread::sleep(Duration::from_secs(1));
    }
    Ok(())
}