How to Watch for File Changes in Rust (notify crate)

Use the notify crate to create a Watcher that listens for events on a specific path and processes them in a callback. Add the dependency, create a watcher, and handle events like Write or Modify to trigger your logic.

use notify::{Config, Event, RecommendedWatcher, Result, Watcher};

fn main() -> Result<()> {
    let mut watcher = RecommendedWatcher::new(
        |res: Result<Event>| {
            if let Ok(event) = res {
                println!("Event: {:?}", event);
            }
        },
        Config::default(),
    )?;

    watcher.watch("./src", notify::RecursiveMode::Recursive)?;
    loop {}
}

Add notify = "6.0" to your Cargo.toml.

Watching for file changes in Rust with the notify crate sets up a background process that monitors a folder for updates. When a file is saved or modified, your code runs automatically, similar to how a text editor highlights syntax as you type. It is useful for live-reloading servers or auto-saving features.