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
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Script: sets global variables and/or parameters for Commands; the decorated
function will be called by Main/Run before any specified Command
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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
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Alias: registers other names for Commands (e.g. delete / remove / kill)
functions
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Main: if the importing module's name is main, call Run() (this
allows for importing the script as a module)
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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
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abort: quits immediately by raising SystemExit
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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)
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get_response: function for displaying text and getting feedback
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help: quits immediately, but adds a reference to --help in the quit message
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log_exception: logs an exception with logging.logger
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mail: rudimentary mail sender
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OrmFile: lightweight orm -- supports str, int, float, date, time,
datetime, bool, and path (which defaults to str); custom data types can
also be specified
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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)
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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
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'script_command' is the Command selected from the command line (useful when
one needs to call the subcommand directly from a main() function)
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'script_command_name' is the name of the script_command
-
'script_verbosity' is the level of verboseness selected (defaults to 0)
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'script_name' is the name of the script
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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
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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