arseparse 0.1.2

Description:

arseparse 0.1.2

Arseparse is a simple Python utility/micro framework for writing command
line interfaces. It provides some functionality around argparse that
covers some common scenarios.
Installation:
pip install arseparse
Basic usage:
from arseparse import Parser, Option


parser = Parser()


# register a command that returns the square of an int
parser.register('square', lambda value: value**2, [Option('value', type=int)])


# register a command that simply returns a string
parser.register('ping', lambda: 'pong')


# or with a decorator
@parser.register_dec([Option('value', type=int)])
def cube(value):
return value**3


sys.exit(parser.run())
You can then point an application entrypoint to the script or execute
the file: your-entrypoint.py square 2
So far so boring. A more common scenario is to have a config file as the
first argument, parse it, create objects that the command depends on,
and pass those alongside the parsed attributes. The root_options and
bootstrap constructor args to Parser allow us to implement this:
from arseparse import Parser, Option
import myapp


# these are options that come before our main command
root_options = [Option('config', type=str, help='path to ini file')]


# this lets us process/modify the kwargs before we execute the callable.
# we can rely on attributes resulting from root_options to be set.
# here config gets replaced by three objects: settings, db_session and user_svc
def bootstrap(**kwargs):
config_uri = kwargs.pop('config')
settings = myapp.parse_app_config(config_uri)
dbsession = myapp.get_sessionmaker(settings)()
user_svc = myapp.UserService(dbsession)
kwargs.update(dict(settings=settings, dbsession=dbsession, user_svc=user_svc))
return kwargs


parser = Parser(root_options, bootstrap)


@parser.register_dec([Option('username', type=str), Option('secret', type=str)])
def create_user(username, secret, user_svc, **kwargs):
user_svc.create_user(username, secret)


@parser.register_dec([Option('user_id', type=int)])
def ban_user(user_id, user_svc, **kwargs):
user_svc.ban_user(user_id)


@parser.register_dec()
def print_settings(settings, **kwargs):
print(settings)
You can now provide the path to a config file as the first argument:
your-entrypoint.py config.ini ban_user 23
Another common requirement is to be able to jump into a shell where some
objects have been preconfigured for us. Here’s a simple recipe for that:
@parser.register_dec()
def shell(**kwargs):
import IPython
IPython.embed(user_ns=kwargs)
Calling your-entrypoint.py config.ini shell will drop you in an ipython shell where dbsession, settings and user_svc are in scope.