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#!/usr/bin/python
# -*- coding: utf-8 -*-
"""
Ansible module to manage symbolic link alternatives.
(c) 2014, Gabe Mulley <gabe.mulley@gmail.com>
(c) 2015, David Wittman <dwittman@gmail.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/>.
"""
DOCUMENTATION = '''
---
module: alternatives
short_description: Manages alternative programs for common commands
description:
- Manages symbolic links using the 'update-alternatives' tool
- Useful when multiple programs are installed but provide similar functionality (e.g. different editors).
version_added: "1.6"
author:
- "David Wittman (@DavidWittman)"
- "Gabe Mulley (@mulby)"
options:
name:
description:
- The generic name of the link.
required: true
path:
description:
- The path to the real executable that the link should point to.
required: true
link:
description:
- The path to the symbolic link that should point to the real executable.
- This option is required on RHEL-based distributions
required: false
requirements: [ update-alternatives ]
'''
EXAMPLES = '''
- name: correct java version selected
alternatives: name=java path=/usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java
- name: alternatives link created
alternatives: name=hadoop-conf link=/etc/hadoop/conf path=/etc/hadoop/conf.ansible
'''
DEFAULT_LINK_PRIORITY = 50
import re
def main():
module = AnsibleModule(
argument_spec = dict(
name = dict(required=True),
path = dict(required=True),
link = dict(required=False),
),
supports_check_mode=True,
)
params = module.params
name = params['name']
path = params['path']
link = params['link']
UPDATE_ALTERNATIVES = module.get_bin_path('update-alternatives',True)
current_path = None
all_alternatives = []
# Run `update-alternatives --display <name>` to find existing alternatives
(rc, display_output, _) = module.run_command(
['env', 'LC_ALL=C', UPDATE_ALTERNATIVES, '--display', name]
)
if rc == 0:
# Alternatives already exist for this link group
# Parse the output to determine the current path of the symlink and
# available alternatives
current_path_regex = re.compile(r'^\s*link currently points to (.*)$',
re.MULTILINE)
alternative_regex = re.compile(r'^(\/.*)\s-\spriority', re.MULTILINE)
current_path = current_path_regex.search(display_output).group(1)
all_alternatives = alternative_regex.findall(display_output)
if not link:
# Read the current symlink target from `update-alternatives --query`
# in case we need to install the new alternative before setting it.
#
# This is only compatible on Debian-based systems, as the other
# alternatives don't have --query available
rc, query_output, _ = module.run_command(
['env', 'LC_ALL=C', UPDATE_ALTERNATIVES, '--query', name]
)
if rc == 0:
for line in query_output.splitlines():
if line.startswith('Link:'):
link = line.split()[1]
break
if current_path != path:
if module.check_mode:
module.exit_json(changed=True, current_path=current_path)
try:
# install the requested path if necessary
if path not in all_alternatives:
if not link:
module.fail_json(msg="Needed to install the alternative, but unable to do so as we are missing the link")
module.run_command(
[UPDATE_ALTERNATIVES, '--install', link, name, path, str(DEFAULT_LINK_PRIORITY)],
check_rc=True
)
# select the requested path
module.run_command(
[UPDATE_ALTERNATIVES, '--set', name, path],
check_rc=True
)
module.exit_json(changed=True)
except subprocess.CalledProcessError, cpe:
module.fail_json(msg=str(dir(cpe)))
else:
module.exit_json(changed=False)
# import module snippets
from ansible.module_utils.basic import *
main()
|
