It is common task in all web frameworks — to provide an easy way to reload development server on code changes. Most of these frameworks are carrying a reloader's code with themselves. And there isn't any python module, simple enough to use in a small project.

Some times ago, I started to write a chat bot called TheBot and begun to look for a separate server reloader's implementation. And found nothing suitable.

Then, I extracted autoreloader from the Django's codebase and put it into a separate module, which README you are reading now. Code was partly modified, now it allows not only to watch on file changes but also to reload upon a some event.

Reload on some event is a quite useful feature for TheBot, because now he can update himself on a push to the GitHub. A pseudocode for this procedure will look like:

def on_push_to_the_github_master_branch():
    make_git_pull()
    run_pip_install()
    trigger_code_reload()

And I don't need an external watcher to run bot, because now he uses server-reloader.

Here is a simple example, how to use a reloader.

def run_server():
    """Some function, which creates and runs your server."""
    pass

def main():
    server_reloader.main(
        run_server,
        before_reload=lambda: print('Reloading code…')
    )

if __name__ == '__main__':
    main()

If you want to trigger code reloading on some custom event, then just do:

from server_reloader import trigger_reload
trigger_reload()

Many thanks to original authors of the autoreloader, I took as the basis.