Tracing Threads

main.rs

use std::{thread, time::Duration, sync::Arc};
use tracing::{info_span, info, span};
use tracing_subscriber::EnvFilter;
use uuid::Uuid;
use dotenv::dotenv;

fn main() {
    dotenv().ok();

    tracing_subscriber::fmt()
        .with_line_number(true)
        .with_file(true)
        // we can set the log level output via RUST_LOG env variable
        .with_env_filter(EnvFilter::from_default_env())
        .json()
        .flatten_event(true)
        .init();

    let req_id = Uuid::new_v4();
    let stream_id = Uuid::new_v4();
    let replay_type: u8 = 2;

    let span = info_span!(
        "root",
        req_id = req_id.to_string(),
        stream_id = stream_id.to_string(),
        replay_type,
    ).entered();
    let child_span = Arc::new(info_span!("child_span"));

    info!("start");

    let t1_span = child_span.clone();
    let t1_handle = thread::spawn(move|| {
        let _child_span = t1_span.enter();
        info!("started thread 1");
        thread::sleep(Duration::from_secs(1));
        info!("ending thread 1");
    });

    let t2_span = child_span.clone();
    let t2_handle = thread::spawn(move|| {
        let _child_span = t2_span.enter();
        info!("started thread 2");
        thread::sleep(Duration::from_secs(1));
        info!("ending thread 2");
    });

    t1_handle.join().unwrap();
    t2_handle.join().unwrap();

    let t3_span = child_span.clone();
    let t3_handle = thread::spawn(move|| {
        let _child_span = t3_span.enter();
        info!("started thread 3");
        thread::sleep(Duration::from_secs(1));
        
        info_span!("thread_span").in_scope(|| {
            info!("started thread span");
            thread::sleep(Duration::from_secs(1));
            info!("ending thread span");
        });

        info!("ending thread 3");
    });

    t3_handle.join().unwrap();

    info!("end");
}