vmon

A V module for asynchronously watching for file changes in a directory. The module is essentially a wrapper for septag/dmon. It works for Windows, macOS and Linux.

Currently vmon offers a few additional features over the code in dmon.

Automatic shared access to the user data in the callback thread (via sync.Mutex)
Automatic init/free of memory resources on clean program exits

Install

v install https://github.com/larpon/vmon

Usage

For example usage see examples/watch_and_wait

v run ~/.vmodules/vmon/examples/watch_and_wait

To watch a directory asynchronously for file changes simply do:

import os
import vmon

fn watch_callback(watch_id vmon.WatchID, action vmon.Action, root_path string, file_path string, old_file_path string, user_data voidptr) {
	// ... do stuff here
}

fn main() {
	vmon.watch(os.home_dir(), watch_callback, 0, voidptr(0)) or { panic(err) }
	// ... do stuff here, wait or block the main thread, e.g.:
	time.sleep(10 * time.second)
}

Since the file watching is running in it's own thread remember to block your main thread while watching for changes, otherwise the app will exit immediately.

Notes

Please note that septag/dmon is licensed under BSD 2-clause while the V wrapper code is licensed under MIT.

Please also note that your user need correct file permission access to the directories you're trying to watch. So watching a place like /tmp on Unix isn't always possible since this is usually owned by root. However, you're usually allowed to make subdirectories in /tmp which can be watched.

Also please note that currently you won't receive events from changes to directories in the watched path since this is not supported in the C project we rely on.