cli: add sopel-config {list,init,get}

The `sopel-config` is a CLI tool to:

* list existing configuration file from Sopel's homedir
* init a new configuration file in Sopel's homedir
* get a value from a section.option of Sopel's configuration

setup.py

@@ -74,5 +74,10 @@ def read_reqs(path):
     platforms='Linux x86, x86-64',
     install_requires=requires,
     extras_require={'dev': dev_requires},
-    entry_points={'console_scripts': ['sopel = sopel.cli.run:main']},
+    entry_points={
+        'console_scripts': [
+            'sopel = sopel.cli.run:main',
+            'sopel-config = sopel.cli.config:main',
+        ]
+    },
 )

sopel/cli/config.py

@@ -0,0 +1,163 @@
+# coding=utf-8
+"""Sopel Config Command Line Interface (CLI): ``sopel-config``"""
+from __future__ import unicode_literals, absolute_import, print_function, division
+
+import argparse
+import os
+
+from sopel import tools, config
+from . import utils
+
+
+def build_parser():
+    """Configure an argument parser for ``sopel-config``"""
+    parser = argparse.ArgumentParser(
+        description='Sopel configuration tool')
+
+    # Subparser: sopel-config <sub-parser> <sub-options>
+    subparsers = parser.add_subparsers(
+        help='Actions to perform',
+        dest='action')
+
+    # sopel-config list
+    list_parser = subparsers.add_parser(
+        'list',
+        help="List available configurations from Sopel's homedir",
+        description="""
+            List available configurations from Sopel's homedir ({homedir})
+            with the extension "{ext}".
+        """.format(homedir=config.DEFAULT_HOMEDIR, ext='.cfg'))
+    list_parser.add_argument(
+        '-e', '--ext', '--extension',
+        dest='extension',
+        default='.cfg',
+        help='Filter by extension (default to "%(default)s)"')
+    list_parser.add_argument(
+        '-p', '--path',
+        action='store_true',
+        dest='display_path',
+        default=False,
+        help='Display a list of absolute filenames instead of their names')
+
+    # sopel-config init
+    init_parser = subparsers.add_parser(
+        'init',
+        help='Initialize Sopel configuration file',
+        description='Initialize Sopel configuration file')
+    utils.add_common_arguments(init_parser)
+
+    # sopel-config get <section> <key>
+    get_parser = subparsers.add_parser(
+        'get',
+        help="Get a configuration option's value",
+        description="Get a configuration option's value",
+    )
+    get_parser.add_argument('section')
+    get_parser.add_argument('option')
+    utils.add_common_arguments(get_parser)
+
+    return parser
+
+
+def handle_list(options):
+    """Display a list of configuration available from Sopel's homedir
+
+    :param options: parsed arguments
+    :type options: ``argparse.Namespace``
+
+    This command displays an unordered list of config names from Sopel's
+    default homedir, without their extensions::
+
+        $ sopel-config list
+        default
+        custom
+
+    It is possible to filter by extension using the ``-e/--ext/--extension``
+    option; default is ``.cfg`` (the ``.`` prefix is not required).
+    """
+    display_path = getattr(options, 'display_path', False)
+    extension = getattr(options, 'extension', '.cfg')
+    if not extension.startswith('.'):
+        extension = '.' + extension
+    configs = utils.enumerate_configs(config.DEFAULT_HOMEDIR, extension)
+
+    for config_filename in configs:
+        if display_path:
+            print(os.path.join(config.DEFAULT_HOMEDIR, config_filename))
+        else:
+            name, _ = os.path.splitext(config_filename)
+            print(name)
+
+
+def handle_init(options):
+    """Use config wizard to initialize a new configuration file for the bot
+
+    :param options: parsed arguments
+    :type options: ``argparse.Namespace``
+
+    .. note::
+
+       Due to how the config wizard works, the configuration filename's
+       extension **must be** ``.cfg``.
+
+    """
+    config_filename = utils.find_config(
+        config.DEFAULT_HOMEDIR,
+        getattr(options, 'config', None) or 'default')
+    config_name, ext = os.path.splitext(config_filename)
+
+    if ext and ext != '.cfg':
+        tools.stderr('Configuration wizard accepts .cfg files only')
+        return 1
+    elif not ext:
+        config_filename = config_name + '.cfg'
+
+    if os.path.isfile(config_filename):
+        tools.stderr('Configuration file %s already exists' % config_filename)
+        return 1
+
+    print('Starting Sopel config wizard for: %s' % config_filename)
+    config._wizard('all', config_name)
+
+
+def handle_get(options):
+    """Read the settings to display the value of <section> <key>"""
+    try:
+        settings = utils.load_settings(options)
+    except Exception as error:
+        tools.stderr(error)
+        return 2
+
+    section = options.section
+    option = options.option
+
+    # Making sure the section.option exists
+    if not settings.parser.has_section(section):
+        tools.stderr('Section "%s" does not exist' % section)
+        return 1
+    if not settings.parser.has_option(section, option):
+        tools.stderr(
+            'Section "%s" does not have a "%s" option' % (section, option))
+        return 1
+
+    # Display the value
+    print(settings.get(section, option))
+
+
+def main():
+    """Console entry point for ``sopel-config``"""
+    parser = build_parser()
+    options = parser.parse_args()
+    action = options.action
+
+    if not action:
+        parser.print_help()
+        return
+
+    # init command does not require existing settings
+    if action == 'list':
+        return handle_list(options)
+    elif action == 'init':
+        return handle_init(options)
+    elif action == 'get':
+        return handle_get(options)