subparse 0.3.3

Basic Usage

from subparse import CLI

class MyApp(object):
    def __init__(self, args):
        self.args = args

    def info(self, *msg):
        if not self.args.quiet:
            print('[info]', *msg)

def context_factory(cli, args):
    return MyApp(args)

def generic_options(parser):
    parser.add_argument('--quiet', action='store_true',
                        help='turn of debugging')

cli = CLI(version='0.0', context_factory=context_factory)
cli.add_generic_options(generic_options)

@cli.command(__name__ + ':foo_main')
def foo(parser):
    """
    a short description ending in a period.

    a longer description
    """
    parser.add_argument('--bar', action='store_true',
                        help='turn on bar')

def foo_main(app, args):
    app.info('Hello World!')

result = cli.run()
sys.exit(result)

Lazy Decorators

Commands can be defined lazily and picked up later. This removes ordering restrictions between the commands and the cli object.

A module containing commands can be defined irrespective of the actual CLI instance:

# myapp/info.py

from subparse import command

@command('myapp.info:foo_main')
def foo(parser):
    """perform foo"""

Later, when an instance of a CLI is created, the commands can be loaded and registered:

cli = CLI()
cli.load_commands('myapp.info')

Entry Points

Commands may also be defined in external modules and loaded via entry points.

from subparse import cli

cli = CLI()
cli.load_commands_from_entry_point('myapp.commands')

An extension application would then define the external module that should be searched for commands. Again this allows the commands themselves to be defined independently of the main functions, improving import speed.

An extension package should define a module containing the supported commands:

# barpkg/commands.py

from subparse import command

@command('barpkg.bar')
def bar(parser):
    """perform bar"""

The package should also define the function to be called for each command. Optionally in a separate module to avoid importing run-time dependencies during parsing:

# barpkg/bar.py

def main(app, args):
    pass

The package can then broadcast the module barpkg.commands containing the supported commands:

[myapp.commands]
barpkg = barpkg.commands

Now when your extension package is installed the commands will automatically become available.

0.3.3 (2013-08-12)

No functional changes from 0.3.2.

• Improve documentation.

0.3.2 (2013-08-06)

• Add CLI.run API for simply executing the command line.

0.3.1 (2013-08-06)

• Improve the help output.

0.3 (2013-08-06)

• Rename subcommands to commands in the API.

0.2 (2013-08-06)

• Underscores in function names are converted to dashes in their respective subcommand names.

• Add CLI.add_generic_options API.

• Add a new help subcommand, allowing for myapp help foo.

• Allow relative imports in the subcommand specification.

0.1 (2013-08-05)

• Initial Commits