ansible/library/lineinfile

#!/usr/bin/python
# -*- coding: utf-8 -*-

# (c) 2012, Daniel Hokka Zakrisson <daniel@hozac.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.

import re
import os

def present(module, name, regexp, line, insertafter, backup):
    f = open(name, 'rb')
    lines = f.readlines()
    f.close()

    mre = re.compile(regexp)
    if not mre.match(line):
        module.fail_json(msg="line= doesn't match regexp=")

    if insertafter in ('BOF', 'EOF'):
        iare = None
    else:
        iare = re.compile(insertafter)

    index = [-1, -1]
    for lineno in range(0, len(lines)):
        if mre.match(lines[lineno]):
            index[0] = lineno
        elif iare is not None and iare.match(lines[lineno]):
            # + 1 for the next line
            index[1] = lineno + 1

    # Regexp matched a line in the file
    if index[0] != -1:
        if lines[index[0]] == line + os.linesep:
            msg = ''
            changed = False
        else:
            lines[index[0]] = line + os.linesep
            msg = 'line replaced'
            changed = True
    # Add it to the beginning of the file
    elif insertafter == 'BOF':
        lines.insert(0, line + os.linesep)
        msg = 'line added'
        changed = True
    # Add it to the end of the file if requested or if insertafter= didn't match
    elif insertafter == 'EOF' or index[1] == -1:
        lines.append(line + os.linesep)
        msg = 'line added'
        changed = True
    # insertafter= matched
    else:
        lines.insert(index[1], line + os.linesep)
        msg = 'line added'
        changed = True

    if changed:
        if backup:
            module.backuplocal(name)
        f = open(name, 'wb')
        f.writelines(lines)
        f.close()

    module.exit_json(changed=changed, msg=msg)

def absent(module, name, regexp, backup):
    f = open(name, 'rb')
    lines = f.readlines()
    f.close()
    cre = re.compile(regexp)
    found = []
    def matcher(line):
        if cre.match(line):
            found.append(line)
            return False
        else:
            return True
    lines = filter(matcher, lines)
    changed = len(found) > 0
    if changed:
        if backup:
            module.backuplocal(name)
        f = open(name, 'wb')
        f.writelines(lines)
        f.close()
    module.exit_json(changed=changed, found=len(found))

def main():
    module = AnsibleModule(
        argument_spec = dict(
            name=dict(required=True, aliases=['dest', 'destfile']),
            state=dict(default='present', choices=['absent', 'present']),
            regexp=dict(required=True),
            line=dict(aliases=['value']),
            insertafter=dict(default='EOF'),
            backup=dict(default=False, choices=BOOLEANS),
        ),
    )

    params = module.params
    backup = module.boolean(module.params.get('backup', False))

    if params['state'] == 'present':
        if 'line' not in params:
            module.fail_json(msg='line= is required with state=present')
        present(module, params['name'], params['regexp'], params['line'],
                params['insertafter'], backup)
    else:
        absent(module, params['name'], params['regexp'], backup)

# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>

main()