A minimalist Python application framework

Flam provides utility functions and classes used in 99% of applications (that I write).

Currently it provides:

• Application bootstrapping.
• Flag management.
• Command-line commands.

Application bootstrapping

Typically all an application writer wants to do is run a main() function, register some flags, maybe take some action based on a command-line argument, set up logging defaults.

Releasepeace's "run" command takes care of all this:

from flam import define_flag, flags, command, run

define_flag('-l', '--long_listing', help='long listing', default=False, action='store_true')

@command def ls(path):

if flags.long_listing:

...

else:

...

def main(args):

# Some initialisation code here... ...

if __name__ == '__main__':

run(main)

run() will parse command line flags, call main with any remaining arguments, then finally dispatch to any commands registered with @command, in this case "ls".

Command Management

Flam provides support for both command-line flags and commands, where commands are actions passed on the command-line.

For example, the following will register an "init" command:

@command def init(path):

"""Initialise the system.""" db = sqlite3.open(path) ...

Which can then be used like so:

$ python myapp.py init somefile.db

Help is automatically generated by inspecting the registered command functions:

$ python myapp.py help Usage: myapp.py [<options>] <command> ...

Commands:

help [<command>]

Display help on available commands.

init <path>

Initialise the system.

Options:

-h, --help	show this help message and exit
--flags=FILE	load flags from FILE
--logging=LEVEL
	set log level to debug, info, warning, error or fatal [warning]

Flag Management

Register new flags with flam.define_flag(). This is an alias for optparse.OptionParser.add_option() and thus accepts exactly the same arguments.

The underlying optparse.OptionParser object is exposed as flam.flag_parser.

Call flam.parse_args() to parse command-line arguments. Defaults to parsing sys.argv[1:].

flam.flags is an optparse.Values() object that will contain the parsed flag values.

The --flags=FILE flag can be used to load flag values from a file consisting of "key = value" lines. Both empty lines and those beginning with # are ignored.