146 lines
4.8 KiB
Python
Executable file
146 lines
4.8 KiB
Python
Executable file
#!/usr/bin/python
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# -*- coding: utf-8 -*-
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"""
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Ansible module to manage symbolic link alternatives.
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(c) 2014, Gabe Mulley <gabe.mulley@gmail.com>
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(c) 2015, David Wittman <dwittman@gmail.com>
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This file is part of Ansible
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Ansible is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Ansible is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Ansible. If not, see <http://www.gnu.org/licenses/>.
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"""
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DOCUMENTATION = '''
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---
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module: alternatives
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short_description: Manages alternative programs for common commands
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description:
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- Manages symbolic links using the 'update-alternatives' tool
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- Useful when multiple programs are installed but provide similar functionality (e.g. different editors).
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version_added: "1.6"
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author:
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- "David Wittman (@DavidWittman)" <dwittman@gmail.com>
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- "Gabe Mulley (@mulby)" <gabe.mulley@gmail.com>
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options:
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name:
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description:
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- The generic name of the link.
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required: true
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path:
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description:
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- The path to the real executable that the link should point to.
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required: true
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link:
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description:
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- The path to the symbolic link that should point to the real executable.
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- This option is required on RHEL-based distributions
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required: false
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requirements: [ update-alternatives ]
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'''
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EXAMPLES = '''
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- name: correct java version selected
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alternatives: name=java path=/usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java
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- name: alternatives link created
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alternatives: name=hadoop-conf link=/etc/hadoop/conf path=/etc/hadoop/conf.ansible
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'''
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DEFAULT_LINK_PRIORITY = 50
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import re
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def main():
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module = AnsibleModule(
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argument_spec = dict(
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name = dict(required=True),
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path = dict(required=True),
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link = dict(required=False),
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),
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supports_check_mode=True,
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)
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params = module.params
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name = params['name']
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path = params['path']
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link = params['link']
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UPDATE_ALTERNATIVES = module.get_bin_path('update-alternatives',True)
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current_path = None
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all_alternatives = []
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# Run `update-alternatives --display <name>` to find existing alternatives
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(rc, display_output, _) = module.run_command(
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[UPDATE_ALTERNATIVES, '--display', name]
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)
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if rc == 0:
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# Alternatives already exist for this link group
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# Parse the output to determine the current path of the symlink and
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# available alternatives
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current_path_regex = re.compile(r'^\s*link currently points to (.*)$',
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re.MULTILINE)
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alternative_regex = re.compile(r'^(\/.*)\s-\spriority', re.MULTILINE)
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current_path = current_path_regex.search(display_output).group(1)
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all_alternatives = alternative_regex.findall(display_output)
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if not link:
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# Read the current symlink target from `update-alternatives --query`
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# in case we need to install the new alternative before setting it.
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#
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# This is only compatible on Debian-based systems, as the other
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# alternatives don't have --query available
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rc, query_output, _ = module.run_command(
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[UPDATE_ALTERNATIVES, '--query', name]
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)
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if rc == 0:
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for line in query_output.splitlines():
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if line.startswith('Link:'):
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link = line.split()[1]
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break
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if current_path != path:
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if module.check_mode:
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module.exit_json(changed=True, current_path=current_path)
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try:
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# install the requested path if necessary
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if path not in all_alternatives:
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if not link:
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module.fail_json(msg="Needed to install the alternative, but unable to do so as we are missing the link")
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module.run_command(
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[UPDATE_ALTERNATIVES, '--install', link, name, path, str(DEFAULT_LINK_PRIORITY)],
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check_rc=True
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)
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# select the requested path
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module.run_command(
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[UPDATE_ALTERNATIVES, '--set', name, path],
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check_rc=True
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)
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module.exit_json(changed=True)
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except subprocess.CalledProcessError, cpe:
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module.fail_json(msg=str(dir(cpe)))
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else:
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module.exit_json(changed=False)
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# import module snippets
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from ansible.module_utils.basic import *
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main()
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