arguments 40

Argument parser based on docopt

Argument parser based on docopt

install

pip install arguments

help highlighted

Setting custom help is easy, override from the BaseArgument class and call set_command_help

self.set_command_help("status", "ssh-config data combined with other data")

example

Please look at the class VagrantArguments in the file below for an example.

https://github.com/erikdejonge/k8svag/blob/master/k8svag/init.py

screenshot

cmdhelp

usage

Docopt is used for parsing the docstring (doc), arguments bundles the schema parser and returns a OptionParser like object with normalized attributes

For example

# coding=utf-8
"""
arguments test

Usage:
  tests.py [options] <posarg1> <posarg2>

Options:
  -h --help                     Show this screen.
  -o --option=<option1>         An option.
  --opt2=<option2>              An option [default: hello].
  -p --parameter=<parameter>    Folder to check the git repos out [default: 77].
  -v --verbose                  Folder from where to run the command [default: .].
"""

from arguments import Arguments

def main():
    """
    main
    """
    arg = Arguments()
    print(arg)


if __name__ == "__main__":
    main()

gives

$ python main.py pval1 pval2
<arguments.Arguments object at 0x1022e0eb8>
options :
    opt2 : hello
    option : None
    parameter : 77
    help : False
    verbose : False
positional :
    posarg1 : pval1
    posarg2 : pval2

---

usage with classes

(examples/classbased.py)

A nested docker style commandline program (python3)

class BaseArguments(arguments.Arguments):
    def __init__(self, doc):
        ...

class MainArguments(BaseArguments):
    def __init__(self):
        doc = """
            Some tools.
            Usage:
                classbased.py [options] [--] <tool> [<args>...]

            Options:
                -h --help       Show this screen..
                -v --verbose    Verbose mode.

            Commands:
                tool1   Tool1 description here
                tool2   Tool2 ...
        """
        super().__init__(doc)


class Tool1Arguments(BaseArguments):
    def __init__(self):
        doc = """
            Tool 1
            Usage:
                classbased.py tool1 [options] [--] <command> [<args>...]

            Options:
                -h --help       Show this screen..
                -v --verbose    Verbose mode.

            Commands:
                run     Run the tool
                build   Build the tool
        """
        super().__init__(doc)


class Tool2Arguments(BaseArguments):
    def __init__(self):
        doc = """
            Tool 2
            Usage:
                classbased.py tool2 [options] [--] <command> [<args>...]

            Options:
                -h --help       Show this screen..
                -v --verbose    Verbose mode.

            Commands:
                upload  Upload something
                delete  Delete something
        """
        super().__init__(doc)

$ python classbased.py
Usage:
    classbased.py [options] [--] <tool> [<args>...]

$ python classbased.py -h
Some tools.
Usage:
    classbased.py [options] [--] <tool> [<args>...]

Options:
    -h --help       Show this screen..
    -v --verbose    Verbose mode.

Commands:
    tool1   Tool1 description here
    tool2   Tool2 ...

$ python classbased.py tool1 run
<__main__.Tool1Arguments object at 0x10d45cac8>
options:
    help: False
    verbose: False
positional:
    args: []
    command: run

---

Using schema

Assume you are using docopt with the following usage-pattern:

my_program.py [--count=N] <path> <files>

and you would like to validate that <files> are readable, and that <path> exists, and that --count is either integer from 0 to 5, or None.

this is how you validate it using schema:

>>> from arguments import *

>>> s = Schema({'<files>': [Use(open)],
...             '<path>': os.path.exists,
...             '--count': Or(None, And(Use(int), lambda n: 0 < n < 5))})

>>> args = Arguments(validateschema=s)

>>> args.files
[<open file 'LICENSE-MIT', mode 'r' at 0x...>, <open file 'setup.py', mode 'r' at 0x...>]

>>> args.path
'../'

>>> args.count
3

As you can see, it validated data successfully, opened files and converted '3' to int.