HN example without crossbeam

main.rs

use serde::Deserialize;
use std::sync::{Arc, Mutex};

const STORIES_URL: &str = "https://hacker-news.firebaseio.com/v0/topstories.json";
const ITEM_URL_BASE: &str = "https://hacker-news.firebaseio.com/v0/item";

#[derive(Deserialize)]
struct Story {
    title: String,
}

fn main() {
    let story_ids: Arc<Vec<u64>> = Arc::new(reqwest::get(STORIES_URL).unwrap().json().unwrap());
    // AtomicUsize would be simpler than Mutex<usize> here, but the point of
    // this is to give a Mutex example.
    let cursor = Arc::new(Mutex::new(0));
    let mut handles = Vec::new();
    for _ in 0..8 {
        let cursor = cursor.clone();
        let story_ids = story_ids.clone();
        handles.push(std::thread::spawn(move || loop {
            let index = {
                let mut cursor_guard = cursor.lock().unwrap();
                let index = *cursor_guard;
                if index >= story_ids.len() {
                    return;
                }
                *cursor_guard += 1;
                index
            };
            let story_url = format!("{}/{}.json", ITEM_URL_BASE, story_ids[index]);
            let story: Story = reqwest::get(&story_url).unwrap().json().unwrap();
            println!("{}", story.title);
        }));
    }
    for handle in handles {
        handle.join().unwrap();
    }
}