textual app devtools

edit✏️

I am working through the textual tutorial, and I want to put it in a proper cli that I can pip install and run the command without textual run --dev app.py. This is a fine pattern, but I also want this to work when I don't have a file to run.

"An astronaut working in a lab, hacking on a computer terminal, htop is running, shallow depth of field beakers, test tubes, volumetric lighting, pink lighting, by victo ngai, killian eng vibrant colours, dynamic lighting, digital art" -s50 -W768 -H448 -C7.5 -Ak_lms -S3617210203

pyproject.toml entrypoints

I setup a new project running hatch new, and added the following entrypoint, giving me a tutorial cli command to run.

...

[project.scripts]
tutorial = 'textual_tutorial.tui:tui'

https://waylonwalker.com/hatch-new-cli/

setup.py entrypoints

If you are using setup.py, you can set up entrypoints in the setup command.

from setuptools import setup

setup(
    ...
    entry_points={
        "console_scripts": ["tutorial = textual_tutorial.tui:tui"],
    },
    ...
)

https://waylonwalker.com/minimal-python-package/

tui.py

adding features

Now to get devtools through a cli without running through textual run --dev. I pulled open the textual cli source code, and this is what it does currently.

Note: I used sys.argv as a very simple way to implement a --dev flag in the tutorial. For a real project, I'd setup argparse, click, or typer. typer is my go to these days, unless I am really trying to limit dependencies, then the standard library argparse might be what I go with.

def tui():

    from textual.features import parse_features
    import os
    import sys

    dev = "--dev" in sys.argv # this works, but putting it behind argparse, click, or typer would be much better

    features = set(parse_features(os.environ.get("TEXTUAL", "")))
    if dev:
        features.add("debug")
        features.add("devtools")

    os.environ["TEXTUAL"] = ",".join(sorted(features))
    app = StopwatchApp()
    app.run()


if __name__ == "__main__":
    tui()

Other Flags???

If you look at the source, there is one other flag for headless mode.

FEATURES: Final = {"devtools", "debug", "headless"}

Run it

Here it is running with tutorial --dev on the left, and textual console on the right.

textual-tutorial-devtools