Simple Reload

Simple library to automatically restart Python scripts on source changes

A lightweight utility that monitors Python files for changes and automatically restarts your script when changes are detected. Perfect for development workflows where you want to see immediate results without manually restarting your application.

import mymodule
from simple_reload import run_simple_reload


def main():
    run_simple_reload([mymodule])
    print('Hello, running my CLI.')

    # Main logic
    from time import sleep
    try:
        while True: sleep(1)
    except KeyboardInterrupt:
        print('Exiting program (potentially due to file change)')


if __name__ == "__main__":
    main()

Installation

pip install simple-reload

Detailed Usage

run_simple_reload takes two main parameters:

1. modules: A list of modules to watch for changes. The function will monitor all Python files in the directories containing these modules.
2. on_change: Optional callback function that gets called when files change. It receives a set of tuples with the change type and file path.

You can conditionally call run_simple_reload if you'd like to only enable it in debug mode. You can also the auto-reload feature by setting the environment variable SIMPLE_RELOAD_DISABLE=1.

Detailed example:

import myapp
from simple_reload import run_simple_reload, Change
from contextlib import suppress


def main():
    if myapp.is_debug_enabled():
        run_simple_reload([myapp], on_change=print)
    
    with supress(KeyboardInterrupt):
        myapp.start()


if __name__ == "__main__":
    main()

When a file changes, the child process is cleanly shutdown (via SIGINT) and a new child is spawned with the same command line arguments that were used to start it originally.

Development

Simple Reload uses Rye for dependency management and the development workflow. To get started with development, ensure you have Rye installed and then clone the repository and set up the environment:

git clone https://github.com/MatthewScholefield/simple-reload.git
cd simple-reload
rye sync
rye run pre-commit install

# Run tests
rye test