#!/usr/bin/python
# -*- coding: utf-8 -*-
# Copyright: (c) 2014, Gabe Mulley <gabe.mulley@gmail.com>
# Copyright: (c) 2015, David Wittman <dwittman@gmail.com>
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
from __future__ import absolute_import, division, print_function
__metaclass__ = type
DOCUMENTATION = r'''
---
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).
author:
- David Wittman (@DavidWittman)
- Gabe Mulley (@mulby)
options:
name:
description:
- The generic name of the link.
type: str
required: true
path:
description:
- The path to the real executable that the link should point to.
type: path
required: true
link:
description:
- The path to the symbolic link that should point to the real executable.
- This option is always required on RHEL-based distributions. On Debian-based distributions this option is
required when the alternative I(name) is unknown to the system.
type: path
priority:
description:
- The priority of the alternative.
type: int
default: 50
state:
description:
- C(present) - install the alternative (if not already installed), but do
not set it as the currently selected alternative for the group.
- C(selected) - install the alternative (if not already installed), and
set it as the currently selected alternative for the group.
choices: [ present, selected ]
default: selected
type: str
version_added: 4.8.0
requirements: [ update-alternatives ]
'''
EXAMPLES = r'''
- name: Correct java version selected
community.general.alternatives:
name: java
path: /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java
- name: Alternatives link created
community.general.alternatives:
name: hadoop-conf
link: /etc/hadoop/conf
path: /etc/hadoop/conf.ansible
- name: Make java 32 bit an alternative with low priority
community.general.alternatives:
name: java
path: /usr/lib/jvm/java-7-openjdk-i386/jre/bin/java
priority: -10
- name: Install Python 3.5 but do not select it
community.general.alternatives:
name: python
path: /usr/bin/python3.5
link: /usr/bin/python
state: present
'''
import os
import re
import subprocess
from ansible.module_utils.basic import AnsibleModule
class AlternativeState:
PRESENT = "present"
SELECTED = "selected"
@classmethod
def to_list(cls):
return [cls.PRESENT, cls.SELECTED]
def main():
module = AnsibleModule(
argument_spec=dict(
name=dict(type='str', required=True),
path=dict(type='path', required=True),
link=dict(type='path'),
priority=dict(type='int', default=50),
state=dict(
type='str',
choices=AlternativeState.to_list(),
default=AlternativeState.SELECTED,
),
),
supports_check_mode=True,
)
params = module.params
name = params['name']
path = params['path']
link = params['link']
priority = params['priority']
state = params['state']
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, dummy) = 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-\s(?:family\s\S+\s)?priority', re.MULTILINE)
match = current_path_regex.search(display_output)
if match:
current_path = match.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, dummy = 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
changed = False
if current_path != path:
# Check mode: expect a change if this alternative is not already
# installed, or if it is to be set as the current selection.
if module.check_mode:
module.exit_json(
changed=(
path not in all_alternatives or
state == AlternativeState.SELECTED
),
current_path=current_path,
)
try:
# install the requested path if necessary
if path not in all_alternatives:
if not os.path.exists(path):
module.fail_json(msg="Specified path %s does not exist" % path)
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(priority)],
check_rc=True
)
changed = True
# set the current selection to this path (if requested)
if state == AlternativeState.SELECTED:
module.run_command(
[UPDATE_ALTERNATIVES, '--set', name, path],
check_rc=True
)
changed = True
except subprocess.CalledProcessError as cpe:
module.fail_json(msg=str(dir(cpe)))
elif current_path == path and state == AlternativeState.PRESENT:
# Case where alternative is currently selected, but state is set
# to 'present'. In this case, we set to auto mode.
if module.check_mode:
module.exit_json(changed=True, current_path=current_path)
changed = True
try:
module.run_command(
[UPDATE_ALTERNATIVES, '--auto', name],
check_rc=True,
)
except subprocess.CalledProcessError as cpe:
module.fail_json(msg=str(dir(cpe)))
module.exit_json(changed=changed)
if __name__ == '__main__':
main()