I am developing a command-line toolset for a project. The final tool shall support many subcommands, like so
foo command1 [--option1 [value]?]*
So there can be subcommands like
foo create --option1 value --
foo make file1 --option2 --option3
The tool uses the argparse library for handling command-line arguments and help functionality etc.
A few additional requirements and constraints:
Some options and functionality is identical for all subcommands (e.g. parsing a YAML configuration file etc.)
Some subcommands are quick and simple to code, because they e.g. just call an external bash script.
Some subcommands will be complex and hence long code.
Help for the basic tool should be available as well as for an individual subcommand:
foo help Available commands are: make, create, add, xyz
foo help make Details for the make subcommand
error codes should be uniform across the subcommands (like the same error code for "file not found")
For debugging purposes and for making progress with self-contained functionality for minimal viable versions, I would like to develop some subcommands as self-containted scripts and modules, like
make.py
that can be imported into the main foo.py script and later on invoked as both
make.py --option1 value etc.
and
foo.py make --option1 value
Now, my problem is: What is the best way to modularize such a complex CLI tool with minimal redundancy (e.g. the arguments definition and parsing should only be coded in one component)?
Option 1: Put everything into one big script, but that will become difficult to manage.
Option 2: Develop the functionality for a subcommand in individual modules / files (like make.py, add.py); but such must remain invocable (via if __name__ == '__main__' ...).
The functions from the subcommand modules could then be imported into the main script, and the parser and arguments from the subcommand added as a subparser.
Option 3: The main script could simply reformat the call to a subcommand to subprocess, like so
subprocess.run('./make.py {arguments}', shell=True, check=True, text=True)
Thanks for all of your suggestions!
I think the most elegant approach is using Typer and following this recipe: