Add the cronvar module.
This manages environment variables in Vixie crontabs. It includes addition/removal/replacement of variables and ordering via the insertbefore/insertafter parameters.
This commit is contained in:
Doug Luce
Allen Luce
parent
2c2a106321
commit
1fa73cd0a3
1 changed files with 430 additions and 0 deletions
430
system/cronvar.py
Executable file
430
system/cronvar.py
Executable file
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#!/usr/bin/python
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# -*- coding: utf-8 -*-
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#
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# This file is part of Ansible
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#
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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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#
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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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#
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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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# Cronvar Plugin: The goal of this plugin is to provide an indempotent
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# method for set cron variable values. It should play well with the
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# existing cron module as well as allow for manually added variables.
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# Each variable entered will be preceded with a comment describing the
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# variable so that it can be found later. This is required to be
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# present in order for this plugin to find/modify the variable
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#
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# This module is based on the crontab module.
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#
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DOCUMENTATION = """
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---
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module: cronvar
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short_description: Manage variables in crontabs
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description:
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- Use this module to manage crontab variables. This module allows
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you to create, update, or delete cron variable definitions.
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version_added: "2.0"
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options:
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name:
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description:
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- Name of the crontab variable.
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default: null
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required: true
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value:
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description:
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- The value to set this variable to. Required if state=present.
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required: false
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default: null
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insertafter:
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required: false
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default: null
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description:
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- Used with C(state=present). If specified, the variable will be inserted
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after the variable specified.
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insertbefore:
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required: false
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default: null
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description:
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- Used with C(state=present). If specified, the variable will be inserted
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just before the variable specified.
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state:
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description:
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- Whether to ensure that the variable is present or absent.
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required: false
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default: present
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choices: [ "present", "absent" ]
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user:
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description:
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- The specific user whose crontab should be modified.
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required: false
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default: root
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cron_file:
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description:
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- If specified, uses this file in cron.d instead of an individual user's crontab.
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required: false
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default: null
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backup:
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description:
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- If set, create a backup of the crontab before it is modified.
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The location of the backup is returned in the C(backup) variable by this module.
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required: false
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default: false
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requirements:
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- cron
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author: Doug Luce
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"""
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EXAMPLES = '''
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# Ensure a variable exists.
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# Creates an entry like "EMAIL=doug@ansibmod.con.com"
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- cronvar: name="EMAIL" value="doug@ansibmod.con.com"
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# Make sure a variable is gone. This will remove any variable named
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# "LEGACY"
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- cronvar: name="LEGACY" state=absent
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# Adds a variable to a file under /etc/cron.d
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- cronvar: name="LOGFILE" value="/var/log/yum-autoupdate.log"
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user="root" cron_file=ansible_yum-autoupdate
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'''
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import os
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import re
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import tempfile
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import platform
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import pipes
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import shlex
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CRONCMD = "/usr/bin/crontab"
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class CronVarError(Exception):
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pass
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class CronVar(object):
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"""
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CronVar object to write variables to crontabs.
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user - the user of the crontab (defaults to root)
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cron_file - a cron file under /etc/cron.d
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"""
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def __init__(self, module, user=None, cron_file=None):
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self.module = module
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self.user = user
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if self.user is None:
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self.user = 'root'
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self.lines = None
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self.wordchars = ''.join(chr(x) for x in range(128) if chr(x) not in ('=', "'", '"', ))
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# select whether we dump additional debug info through syslog
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self.syslogging = False
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if cron_file:
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self.cron_file = '/etc/cron.d/%s' % cron_file
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else:
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self.cron_file = None
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self.read()
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def read(self):
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# Read in the crontab from the system
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self.lines = []
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if self.cron_file:
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# read the cronfile
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try:
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f = open(self.cron_file, 'r')
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self.lines = f.read().splitlines()
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f.close()
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except IOError, e:
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# cron file does not exist
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return
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except:
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raise CronVarError("Unexpected error:", sys.exc_info()[0])
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else:
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# using safely quoted shell for now, but this really should be two non-shell calls instead. FIXME
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(rc, out, err) = self.module.run_command(self._read_user_execute(), use_unsafe_shell=True)
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if rc != 0 and rc != 1: # 1 can mean that there are no jobs.
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raise CronVarError("Unable to read crontab")
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lines = out.splitlines()
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count = 0
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for l in lines:
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if count > 2 or (not re.match( r'# DO NOT EDIT THIS FILE - edit the master and reinstall.', l) and
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not re.match( r'# \(/tmp/.*installed on.*\)', l) and
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not re.match( r'# \(.*version.*\)', l)):
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self.lines.append(l)
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count += 1
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def log_message(self, message):
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if self.syslogging:
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syslog.syslog(syslog.LOG_NOTICE, 'ansible: "%s"' % message)
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def write(self, backup_file=None):
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"""
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Write the crontab to the system. Saves all information.
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"""
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if backup_file:
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fileh = open(backup_file, 'w')
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elif self.cron_file:
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fileh = open(self.cron_file, 'w')
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else:
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filed, path = tempfile.mkstemp(prefix='crontab')
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fileh = os.fdopen(filed, 'w')
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fileh.write(self.render())
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fileh.close()
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# return if making a backup
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if backup_file:
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return
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# Add the entire crontab back to the user crontab
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if not self.cron_file:
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# quoting shell args for now but really this should be two non-shell calls. FIXME
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(rc, out, err) = self.module.run_command(self._write_execute(path), use_unsafe_shell=True)
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os.unlink(path)
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if rc != 0:
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self.module.fail_json(msg=err)
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def remove_variable_file(self):
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try:
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os.unlink(self.cron_file)
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return True
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except OSError, e:
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# cron file does not exist
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return False
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except:
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raise CronVarError("Unexpected error:", sys.exc_info()[0])
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def parse_for_var(self, line):
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lexer = shlex.shlex(line)
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lexer.wordchars = self.wordchars
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varname = lexer.get_token()
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is_env_var = lexer.get_token() == '='
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value = ''.join(lexer)
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if is_env_var:
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return (varname, value)
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raise CronVarError("Not a variable.")
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def find_variable(self, name):
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comment = None
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for l in self.lines:
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try:
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(varname, value) = self.parse_for_var(l)
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if varname == name:
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return value
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except CronVarError:
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pass
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return None
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def get_var_names(self):
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var_names = []
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for l in self.lines:
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try:
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(var_name, _) = self.parse_for_var(l)
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var_names.append(var_name)
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except CronVarError:
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pass
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return var_names
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def add_variable(self, name, value, insertbefore, insertafter):
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if insertbefore is None and insertafter is None:
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# Add the variable to the top of the file.
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self.lines.insert(0, "%s=%s" % (name, value))
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else:
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newlines = []
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for l in self.lines:
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try:
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(varname, _) = self.parse_for_var(l) # Throws if not a var line
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if varname == insertbefore:
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newlines.append("%s=%s" % (name, value))
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newlines.append(l)
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elif varname == insertafter:
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newlines.append(l)
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newlines.append("%s=%s" % (name, value))
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else:
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raise CronVarError # Append.
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except CronVarError:
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newlines.append(l)
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self.lines = newlines
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def remove_variable(self, name):
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self.update_variable(name, None, remove=True)
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def update_variable(self, name, value, remove=False):
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newlines = []
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for l in self.lines:
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try:
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(varname, _) = self.parse_for_var(l) # Throws if not a var line
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if varname != name:
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raise CronVarError # Append.
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if not remove:
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newlines.append("%s=%s" % (name, value))
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except CronVarError:
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newlines.append(l)
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self.lines = newlines
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def render(self):
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"""
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Render a proper crontab
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"""
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result = '\n'.join(self.lines)
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if result and result[-1] not in ['\n', '\r']:
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result += '\n'
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return result
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def _read_user_execute(self):
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"""
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Returns the command line for reading a crontab
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"""
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user = ''
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if self.user:
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if platform.system() == 'SunOS':
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return "su %s -c '%s -l'" % (pipes.quote(self.user), pipes.quote(CRONCMD))
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elif platform.system() == 'AIX':
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return "%s -l %s" % (pipes.quote(CRONCMD), pipes.quote(self.user))
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elif platform.system() == 'HP-UX':
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return "%s %s %s" % (CRONCMD , '-l', pipes.quote(self.user))
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else:
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user = '-u %s' % pipes.quote(self.user)
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return "%s %s %s" % (CRONCMD , user, '-l')
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def _write_execute(self, path):
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"""
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Return the command line for writing a crontab
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"""
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user = ''
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if self.user:
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if platform.system() in ['SunOS', 'HP-UX', 'AIX']:
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return "chown %s %s ; su '%s' -c '%s %s'" % (pipes.quote(self.user), pipes.quote(path), pipes.quote(self.user), CRONCMD, pipes.quote(path))
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else:
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user = '-u %s' % pipes.quote(self.user)
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return "%s %s %s" % (CRONCMD , user, pipes.quote(path))
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#==================================================
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def main():
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# The following example playbooks:
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#
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# - cronvar: name="SHELL" value="/bin/bash"
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#
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# - name: Set the email
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# cronvar: name="EMAILTO" value="doug@ansibmod.con.com"
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#
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# - name: Get rid of the old new host variable
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# cronvar: name="NEW_HOST" state=absent
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#
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# Would produce:
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# SHELL = /bin/bash
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# EMAILTO = doug@ansibmod.con.com
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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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value=dict(required=False),
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user=dict(required=False),
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cron_file=dict(required=False),
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insertafter=dict(default=None),
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insertbefore=dict(default=None),
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state=dict(default='present', choices=['present', 'absent']),
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backup=dict(default=False, type='bool'),
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),
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mutually_exclusive=[['insertbefore', 'insertafter']],
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supports_check_mode=False,
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)
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name = module.params['name']
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value = module.params['value']
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user = module.params['user']
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cron_file = module.params['cron_file']
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insertafter = module.params['insertafter']
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insertbefore = module.params['insertbefore']
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state = module.params['state']
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backup = module.params['backup']
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ensure_present = state == 'present'
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changed = False
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res_args = dict()
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# Ensure all files generated are only writable by the owning user. Primarily relevant for the cron_file option.
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os.umask(022)
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cronvar = CronVar(module, user, cron_file)
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if cronvar.syslogging:
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syslog.openlog('ansible-%s' % os.path.basename(__file__))
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syslog.syslog(syslog.LOG_NOTICE, 'cronvar instantiated - name: "%s"' % name)
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# --- user input validation ---
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if name is None and ensure_present:
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module.fail_json(msg="You must specify 'name' to insert a new cron variabale")
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if value is None and ensure_present:
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module.fail_json(msg="You must specify 'value' to insert a new cron variable")
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if name is None and not ensure_present:
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module.fail_json(msg="You must specify 'name' to remove a cron variable")
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# if requested make a backup before making a change
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if backup:
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(_, backup_file) = tempfile.mkstemp(prefix='cronvar')
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cronvar.write(backup_file)
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if cronvar.cron_file and not name and not ensure_present:
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changed = cronvar.remove_job_file()
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module.exit_json(changed=changed, cron_file=cron_file, state=state)
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old_value = cronvar.find_variable(name)
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if ensure_present:
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if old_value is None:
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cronvar.add_variable(name, value, insertbefore, insertafter)
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changed = True
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elif old_value != value:
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cronvar.update_variable(name, value)
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changed = True
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else:
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if old_value is not None:
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cronvar.remove_variable(name)
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changed = True
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res_args = {
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"vars": cronvar.get_var_names(),
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"changed": changed
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}
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if changed:
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cronvar.write()
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# retain the backup only if crontab or cron file have changed
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if backup:
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if changed:
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res_args['backup_file'] = backup_file
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else:
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os.unlink(backup_file)
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if cron_file:
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res_args['cron_file'] = cron_file
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module.exit_json(**res_args)
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# --- should never get here
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module.exit_json(msg="Unable to execute cronvar task.")
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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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