`rich-argparse`

Format argparse help output with rich.

Installation

Copy the file rich_argparse.py to your project.

Usage

Pass the formatter_class to the argument parser

import argparse
from rich_argparse import RichHelpFormatter

parser = argparse.ArgumentParser(..., formatter_class=RichHelpFormatter)
...

Recipes

argparse's subparsers

argparse subparsers do not inherit the formatter class from the parent parser. To have the help text of subparsers formatted with rich, you have to explicitly pass formatter_class to the subparsers:

you can pass it to all subparsers at once:

 subparsers = parser.add_subparsers(
     ..., parser_class=lambda **k: type(parser)(**k, formatter_class=parser.formatter_class),
 )
 p1 = subparsers.add_parser(...)
 p2 = subparsers.add_parser(...)

or to each subparser individually:

 subparsers = parser.add_subparsers(...)
 p1 = subparsers.add_parser(..., formatter_class=parser.formatter_class)
 p2 = subparsers.add_parser(..., formatter_class=parser.formatter_class)

django's commands

django uses argparse for its built in commands as well as for extension libraries and user defined commands. To use rich_argparse with these commands, change your manage.py file as follows:

diff --git a/my_project/manage.py b/my_project/manage.py
index 7fb6855..5e5d48a 100755
--- a/my_project/manage.py
+++ b/my_project/manage.py
@@ -1,22 +1,38 @@
 #!/usr/bin/env python
 """Django's command-line utility for administrative tasks."""
 import os
 import sys


 def main():
     """Run administrative tasks."""
     os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'my_project.settings')
     try:
         from django.core.management import execute_from_command_line
     except ImportError as exc:
         raise ImportError(
             "Couldn't import Django. Are you sure it's installed and "
             "available on your PYTHONPATH environment variable? Did you "
             "forget to activate a virtual environment?"
         ) from exc
+
+    from django.core.management.base import BaseCommand, DjangoHelpFormatter
+    from rich_argparse import RichHelpFormatter
+
+    class RichDjangoHelpFormatter(RichHelpFormatter, DjangoHelpFormatter):  # rich first
+        """A rich-based help formatter for django commands."""
+
+    original_create_parser = BaseCommand.create_parser
+
+    def create_parser(*args, **kwargs):
+        parser = original_create_parser(*args, **kwargs)
+        parser.formatter_class = RichDjangoHelpFormatter  # set the formatter_class
+        return parser
+
+    BaseCommand.create_parser = create_parser
+
     execute_from_command_line(sys.argv)


 if __name__ == '__main__':
     main()

Now try out some command like: python manage.py runserver --help

Special text highlighting

You can highlight patterns in the help text of your CLI. By default, RichHelpFormatter defines the following styles:

>>> pprint(RichHelpFormatter.styles)
{'argparse.args': 'italic cyan',
 'argparse.groups': 'bold italic dark_orange',
 'argparse.help': 'default',
 'argparse.syntax': '#E06C75',
 'argparse.text': 'italic'}

The following example highlights all occurrences of pyproject.toml in green.

# add a style called `pyproject` which applies a green style (any rich style works)
RichHelpFormatter.styles["argparse.pyproject"] = "green"
# add the highlight regex (the regex group name must match an existing style name)
RichHelpFormatter.highlights.append(r"\W(?P<pyproject>pyproject\.toml)\W")
# pass the formatter class to argparse
parser = argparse.ArgumentParser(..., formatter_class=RichHelpFormatter)
...

gridcell/rich-argparse