clinner 0.3.2

Command Line Interface builder that helps creating an entry point for your application.

=======
Clinner
=======

:Version: 0.3.2
:Status: Production/Stable
:Author: José Antonio Perdiguero López

Command Line Interface builder that helps creating an entry point for your application.


Quick start
===========

1. Install this package using pip:

.. code:: bash

pip install clinner

2. Create a command

.. code:: python

from clinner.command import command

@command
def foo(*args, **kwargs):
return True

3. Create a main file:

.. code:: python

from clinner.run.main import Main

if __name__ == '__main__':
sys.exit(Main().run())

Commands
========
Commands are declared using a decorator to register given functions. Commands are functions with the follow parameters:

func
Function that will be called when command would be executed.

command_type
Type of the command, could be a *bash* or *python* command.

args
Parser arguments for this command.

parser_opts
Command subparser's keywords, such as description.

This decorator allows to be used as a common decorator without arguments, where default type (*python*) will be used:

.. code:: python
@command
def foobar(bar):
pass

Or specifying the type:

.. code:: python
@command(command_type=Type.python)
def foobar(bar):
pass

But also is possible to provide command line arguments, as expected by argparse.ArgumentParser.add_argument:

.. code:: python
@command(args=((('-f', '--foo'), {'help': 'Foo argument that does nothing'}), # Command argument
(('--bar',), {'action': 'store_true', 'help': 'Bar argument stored as True'})), # Another argument
parser_opts={'title': 'foobar_command', 'help': 'Help for foobar_command'}) # Parser parameters
def foobar(*args, **kwargs):
pass

All commands will be registered in a command register that can be accessed through ``command.register``. Each entry in
this register is a dictionary with the fields declared at the beginning of this section.

Main
====

A main class is defined to ease the creation of command line applications. This class follows the process:

1. Create a parser using ``argparse.ArgumentParser`` for the application:

a) Calling all ``add_arguments(parser)`` methods from all super classes, e.g: ``clinner.mixins.HealthCheckMixin``.
b) Addding a subparser for each command with their specific arguments.

2. Parse arguments using the argument parser created previously.

3. Inject variables into environment calling all super classes methods whose name starts with ``inject_``. Again, e.g: ``clinner.mixins.VaultMixin``.

4. Load settings module from **CLINNER_SETTINGS** environment variable. More details below.


Settings
========

Clinner settings can be specified through **CLINNER_SETTINGS** environment variable or using ``-s`` or ``--settings``
command line flags during invocation. The format to specify settings module or class should be either ``package.module``
or ``package.module:Class``.

Default Arguments
-----------------

Default arguments for commands. Let a command ``foo`` declared:

.. code:: python
default_args = {
'foo': ['-v', '--bar', 'foobar'],
}

Vault
-----

Vault arguments to retrieve secrets from this service and inject them as environment variables:

.. code:: python
vault = {
'url': 'http://vaulturl',
'secrets_path': 'vault_secrets_path_to_retrieve',
'app_id_path': '/path/to/app_id_file',
'user_id_path': '/path/to/user_id_file',
}

Example
=======

Full code example:

.. code:: python
import os
import shlex
import sys

from clinner.command import command, Type as CommandType
from clinner.run.main import Main


@command(command_type=CommandType.bash
args=(('-i', '--input'),
('-o', '--output')))
def foo(*args, **kwargs):
"""List of foo commands"""
ls_cmd = shlex.split('ls')
wc_cmd = shlex.split('wc')
wc_cmd += [kwargs['input'], kwargs['output']]

return [ls_cmd, wc_cmd]


@command(command_type=CommandType.python)
def bar(*args, **kwargs):
"""Do a bar."""
return True


if __name__ == '__main__':
sys.exit(Main().run())