selconfig

#! /usr/bin/env python
'''\
Select the given section of a config file

$Id$
'''

from __future__ import print_function

import argparse
import io
import re
import sys

from expconfig import ConfigObj

from expargparse import assigns_to_dicts, get_key_chain
from feedback import die
import package_info

#
# Main routine
#

# Check command line

command_line = argparse.ArgumentParser(description=__doc__.split('\n', 1)[0])
command_line.add_argument('section',
                          help='section to be selected, in . notation')
command_line.add_argument('config', nargs='?', default='-', 
                          help='original configuration file name [%(default)s]')
command_line.add_argument('-V', '--version', action='version',
                          version=package_info.version)
command_line.add_argument('--inline-comments' , '-c', action='store_true',
                          help='compact white space before inline comments'
                               ' (BETA)')
command_line.add_argument('--trailing-space' , '-t', action='store_true',
                          help='remove white space at end of lines')

args = command_line.parse_args()

# File handling

try:
    config_file = args.config
    if config_file == '-':
        config_file = sys.stdin
    config_data = ConfigObj(config_file, file_error=True)
except IOError as error:
    die(error)

# Walk config to the appropriate section and create output structure

selected_data = ConfigObj(write_empty_values=True,
                          indent_type='  ')
if args.section:
    config = config_data
    selected = selected_data
    for section in reversed(get_key_chain(args.section)):
        if section in config.comments:
            selected.comments[section] = config.comments[section]
        if section in config.inline_comments:
            selected.inline_comments[section] = config.inline_comments[section]
        config = config[section]
        selected[section] = {}
        selected = selected[section]
    # Replace the empty leaf section by the original section to be selected
    selected.parent[section] = config
else:
    selected_data.merge(config_data)

# Ready to roll out

lines = io.BytesIO()
selected_data.write(lines)

lines.seek(0)
for line in io.TextIOWrapper(lines):
    if args.inline_comments: line = re.sub(r' = (.*?)  #', r' = \1 #', line)
    if args.trailing_space:
        print(line.rstrip())
    else:
        print(line, end='')