configarg

This library provides a way to use a config file with the official argparse library.

Installation

Use the package manager pip to install configarg.

pip install configarg

Usage

Assuming you have this JSON file:

{
  "key1": "value1",
  "key2": "value2",
  "nested": {
    "key3": "value3",
  },
}

You can use the file to configure default values of your own parser built with argparse.

import argparse
import configarg

# Build your parser
parser = argparse.ArgumentParser(description="My CLI tool")
parser.add_argument("--config", help="JSON configuration file")
parser.add_argument("--option1")
parser.add_argument("--option2")
parser.add_argument("--option3")

# Read the JSON file from `--config` option
config = Config.read_from_option(parser, "config")

# Assign values from the config file
if config is not None:
  config.configure(parser, {
      "key1": "option1",
      "key2": "option2",
      "nested.key3": "option3", # Nested fields are allowed
  })

args = parser.parse_args(args=["--option2", "value-from-cli"])
assert args.option1 == "value1"
assert args.option2 == "value-from-cli" # Value from command arguments will supersede a default value
assert args.option3 == "value3"

Also, you can use any format of files that can be parsed as a dict object. For example, if you use PyYAML:

...

def load(path):
    with open(path) as f:
        return yaml.load(f, Loader=yaml.CLoader)

config = Config.read_from_option(parser, "config", load)

...

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

MIT