scription 0.83.0

simple script parameter parser

scription

light-weight library to enhance command-line scripts; includes conversion of parameters to specified data types, parameter checking, basic input/output with users, support for suid [1], sending email, executing sub-programs, and having sub-commands within a script

decorators

• Script: sets global variables and/or parameters for Commands; the decorated function will be called by Main/Run before any specified Command

• Command: marks function as a subcommand for the script (e.g. add, delete, list, etc.); if no subcommand is specified on the command-line, scription will look for a Command with the same name as the script

• Alias: registers other names for Commands (e.g. delete / remove / kill)

functions

• Main: if the importing module’s __name__ is __main__, call Run() (this allows for importing the script as a module)

• Run: unconditionally attempts to run the Script function (if any) and the Command found on the command-line

Main() or Run() should be the last thing in the script

classes

• Spec: can be used when defining the command-line parameters (can also just use tuples)

helper functions/classes

• abort: quits immediately by raising SystemExit

• Execute: class for executing other programs; uses subprocess.Popen by default, but if pty=True is specified then pty.fork will be used (handy for programs that only accept input from a pty)

• get_response: function for displaying text and getting feedback

• help: quits immediately, but adds a reference to –help in the quit message

• log_exception: logs an exception with logging.logger

• mail: rudimentary mail sender

• OrmFile: lightweight orm – supports str, int, float, date, time, datetime, bool, and path (which defaults to str); custom data types can also be specified

• print: wrapper around print that adds a ‘verbose_level’ keyword (default: 1); default verbosity is 0 (so print does nothing), but can be increased using -v, -vv, –verbose, or –verbose=2 (in Python 2 the script must use ‘from __future__ import print_function’ to use scription’s print)

• user_ids: context manager useful for suid scripts – all actions taken within the context are run as the user/group specified

features

• extra parameters defined by Script are global, and can be accessed from any function or Command

• ‘module’ is a namespace inserted into the script

• ‘script_command’ is the Command selected from the command line (useful when one needs to call the subcommand directly from a main() function)

• ‘script_command_name’ is the name of the script_command

• ‘script_verbosity’ is the level of verboseness selected (defaults to 0)

• ‘script_name’ is the name of the script

• builtin options are: –help, –verbose (-v or -vv), –version, –all-versions –version attempts to display the version of the main package in use –all-versions attempts to display the versions of any imported packages

• command-line is decoded to unicode under Python 2 (Python 3 does this for us)

[1] I use the suid-python program, available at http://selliott.org/python/suid-python.c