Typer command in a python wrapper script

[cousinbr]

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Example Code

import sys
from my_typer_app.main import app

sys.stdout = open("batch_file_log", mode="at", encoding="ascii", buffering=1)
sys.stderr = open("batch_file_log", mode="at", encoding="ascii", buffering=1)

app()
print("This line is never executed")

Description

Hello,

I have build a CLI with Typer that do some tasks. I have to schedule task execution (with cron for exemple) but for scheduled task, i want to redirect all output (stdin & stderr) to logfile. SO, i have created a python script that import my Typer app "app" and launch it after stdin/stderr redirection

Now, i must retrieve "app" return code to send an alert if this is not 0. How could i do that ?

Thanks

Operating System

Linux

Operating System Details

No response

Typer Version

0.9.0

Python Version

Python 3.8.16

Additional Context

No response

[brianmedigate]

Your script exits before getting to the last print because the app() invocation raises a SystemExit exception, since it is expecting to be the last thing run in the process.

You could try to catch the exception and access the exit code like this:

try:
    app()
except SystemExit as e:
   print(f"Exited with exit code {e.code}")

But a better approach might be to use the CliRunner utility from typer.testing, which is designed to do basically what you are trying to do: run a typer app from the context of a longer-running piece of code. It can also capture the output for you, which might be cleaner than patching stderr and stdout.

You can read more about CliRunner here and here

[YuriiMotov]

I wouldn't use CliRunner for this as it's designed to be used for unit-tests.

The approach with try .. except is working!

import typer

app = typer.Typer()


@app.command()
def create(username: str):
    print(f"Creating user: {username}")


@app.command()
def delete(username: str):
    print(f"Deleting user: {username}")


if __name__ == "__main__":
    try:
        app()
    except SystemExit as e:
        print(f"Exited with exit code {e.code}")

Try

$ python main.py delete us
Deleting user: us
Exited with exit code 0