How to call python function with default values when they are using typer decorated functions

Question

I'm currently migrating some Python functions to be used with the Typer library for a CLI application. Previously, these functions worked well with default parameters, but I'm encountering issues when applying Typer's argument and option decorators, specifically when dealing with default parameter values. I am using Python 3.10.

Here's an example of my code where the issue occurs:

main.py:

import typer

app = typer.Typer()

log_level_arg = typer.Argument(default="debug", help="The output logging level. This can be one of: debug, info, warning, error, and critical.")

@app.command()
def view(log_level: str = log_level_arg):
    """
    View IP address of switch in environment if it exists
    """
    print("log level:")
    print(log_level)
    print(type(log_level))

@app.command()
def view_old(log_level: str = "debug"):
    print("log level:")
    print(log_level)
    print(type(log_level))

print("view:")
view()

print()

print("view old:")
view_old()

Running python main.py view outputs:

python main.py view
view:
log level:
<typer.models.ArgumentInfo object at 0x7f9804e4ceb0>
<class 'typer.models.ArgumentInfo'>

view old:
log level:
debug
<class 'str'>
log level:
debug
<class 'str'>

This bit here is the troublesome part:

view:
log level:
<typer.models.ArgumentInfo object at 0x7f9804e4ceb0>
<class 'typer.models.ArgumentInfo'>

Instead of the log_level argument being recognized as a string with the default value "debug," it's being treated as a typer.models.ArgumentInfo object. This behavior is unexpected and causes subsequent functionality that depends on log_level being a string (e.g., lower() method calls) to fail.

So my question: I guess I can workaround this with additional functions that just wrap the existing ones, but is there perhaps a way to avoid this and do this natively?

Answer 1

Nope not natively possible according to https://github.com/tiangolo/typer/issues/279 though there are workarounds mentioned in that thread.