How to add flags for Typer commands in Python

Question

I am new to Typer but I cannot really find the info I need in the docs...
I am trying to add flags to my app with typer commands. I would like to have:

myApp command1 --flag1 value1 --flag2 value2

Currently I have a plain command that takes a string:

@app.command(
    name="foo",
    help="bar",
)
def command1(path: str) -> None:  # noqa: D401
    """
    Text

    Args:
        path: my favourite path
    """
    # some code here

Is there any way to adjust the function above so that it takes flags+values as in the first box?

Rodrigo Rodrigues · Answer

If you are trying to create a typer script with only one command (command1), then you need to take a look at this documentation page, that tells that there is a "gotcha":

You might have noticed that if you create a single command, (...) Typer is smart enough to create a CLI application with that single function as the main CLI application, not as a command/subcommand:
_{Notice that it doesn't show a command main, even though the function name is main.}

But if you add multiple commands, Typer will create one CLI command for each one of them:

The solution for that is also mentioned later in the docs:

If you want to create a CLI app with one single command but you still want it to be a command/subcommand you can just add a callback

In your case, it could be something similar to this (adjust for your specific program logic):

import typer
app = typer.Typer()

# I am assuming you need a mandatory 'path' and optionals 'flag1' and 'flag2'      
@app.command()
def command1(path: str, flag1: str = 'value1', flag2: str = 'value2'):
    print(f"running on {path} with {flag1} and {flag2}")

# this callback is added as workaround for the "just one command" gotcha
# you can use it for documenting purposes
@app.callback()
def callback():
    """
    Text
    Args:
        path: my favourite path
    """

if __name__ == "__main__":
    app()

Then, it will generate the following --help message:

❯ python3 myApp.py --help

 Usage: myApp.py [OPTIONS] COMMAND [ARGS]...                    
                                                                
 Text Args:     path: my favourite path                         
                                                                 
╭─ Commands ───────────────────────────────────────────────────╮
│ command1                                                     │
╰──────────────────────────────────────────────────────────────╯


❯ python3 myApp.py command1 --help

Usage: myApp.py command1 [OPTIONS] PATH

╭─ Arguments ──────────────────────────────────────────────────╮
│ *    path      TEXT  [default: None] [required]              │
╰──────────────────────────────────────────────────────────────╯
╭─ Options ────────────────────────────────────────────────────╮
│ --flag1        TEXT  [default: value1]                       │
│ --flag2        TEXT  [default: value2]                       │
│ --help               Show this message and exit.             │
╰──────────────────────────────────────────────────────────────╯

How to add flags for Typer commands in Python

1 Answers