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ansible/system/cronvar.py
Brian Coca 3564c48f3c switched to use module loggigng
2015-10-01 00:29:57 -04:00

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