wolph / mainpy

Simplify your project's main entrypoint definition with @main

@main.py

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Basic Examples

Instead of the verbose "boilerplate"

def main(): ...

if __name__ == '__main__':
    main()

mainpy can be used to write it as:

from mainpy import main

@main
def app(): ...

Similarly, the async boilerplate

import asyncio

async def main(): ...

if __name__ == '__main__':
    asyncio.run(main())

can be replaced with

@main
async def async_app(): ...

If, for some reason, you cannot or don't want to use a decorator, you can also call the decorator with the function as an argument:

import mainpy


def main(): ...


mainpy.main(main)

External Libraries

Click

With click you can simply add the decorator as usual, as long as you keep in mind that it has to be the first decorator (i.e. above the @click.command()):

import click

import mainpy


@mainpy.main
@click.command()
def click_command():
    click.echo('Hello from click_command')

If you want to use @click.group you probably don't want to decorate the group because the decorator will immediately execute. In those cases you probably want to move the mainpy.main(...) execution to the bottom of the file:

import click

import mainpy


@click.group()
def group(): ...
    

@group.command()
def command(): ...


mainpy.main(group)

Typer

When using typer you also need to use the regular call instead of the decorator:

import typer

import mainpy


app = typer.Typer()


@app.command()
def command():
    typer.echo('typer.Typer()')


mainpy.main(app)

Automatic uvloop usage

If you have uvloop installed, mainpy will automatically call uvloop.install() before running your async main function. This can be disabled by setting use_uvloop=False, e.g.:

@main(use_uvloop=False)
async def app(): ...

Debug mode

Optionally, python's development mode can be emulated by setting debug=True in @main. This will enable the faulthandler, configure the warnings filter to display all warnings, and activate the asyncio debug mode:

@main(debug=True)
def app(): ...

Installation

pip install mainpy

requires python > 3.7