I was trying to run the example python shiny app directly from a script
"""Test shiny app."""
import argparse
from shiny import App, render, ui
app_ui = ui.page_fluid(
ui.input_slider("n", "N", 0, 100, 20),
ui.output_text_verbatim("txt"),
)
def server(input, output, _session):
@output
@render.text
def txt():
return f"n*2 is {input.n() * 2}."
app = App(app_ui, server)
if __name__ == "__main__":
ap = argparse.ArgumentParser(description="Parse args passed into the Shiny app")
ap.add_argument("--host", help="URL of host", default="127.0.0.1")
ap.add_argument("--port", help="Port to use", type=int, default=8888)
ap.add_argument("--reload", help="Enable auto-reload", action=argparse.BooleanOptionalAction, default=True)
args = ap.parse_args()
app.run(host=args.host, port=args.port, reload=args.reload)
When I run this script from a python environment which has shiny installed as
python test_app.py
I see the following error
WARNING: Current configuration will not reload as not all conditions are met,please refer to documentation.
WARNING: You must pass the application as an import string to enable 'reload' or 'workers'.
It works well if I set reload=False. Is there a workaround for this?
(EDIT: Fixed argparse issue pointed out by @relent95 in the answer)
It's not recommended to run a shiny app directly inside an application main module.
If you insist, use the run_app() like the following. But I'm not sure it will not be broken in the future.
# This is the test_app.py file.
...
app = App(app_ui, server)
if __name__ == "__main__":
...
from shiny import run_app
run_app('test_app:app', host=args.host, port=args.port, reload=True)
As a side note, you incorrectly implemented the --reload option. See the reference.