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community.general/library/system/cron
Patrick Callahan 8f14ffe56b Bug fixes and enhancements. 
Bugs:
(1) no longer allow empty jobs
(2) strip the header added by crontab package used in openSuSE and SuSE
(3) try not to leak temp files when things go wrong
(4) issue returning job names under certain conditions

Enhancements:
(1) Allow all special times not just reboot.
(2) Fail earlier by performing more input validation
(3) Add feature to allow removing cron file under /etc/cron.d

ToDo:
(1) Validate times (minute, hour, ...)
(2) Strip white space from fields such as name and job such that name=foo equals name=' foo'.
(3) More testing
2013-07-09 03:21:40 +00:00

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#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# (c) 2012, Dane Summers <dsummers@pinedesk.biz>
# (c) 2013, Mike Grozak <mike.grozak@gmail.com>
# (c) 2013, Patrick Callahan <pmc@patrickcallahan.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/>.
#
# Cron Plugin: The goal of this plugin is to provide an indempotent method for
# setting up cron jobs on a host. The script will play well with other manually
# entered crons. Each cron job entered will be preceded with a comment
# describing the job so that it can be found later, which is required to be
# present in order for this plugin to find/modify the job.
#
# This module is based on python-crontab by Martin Owens.
#
DOCUMENTATION = """
---
module: cron
short_description: Manage cron.d and crontab entries.
description:
- Use this module to manage crontab entries. This module allows you to create named
crontab entries, update, or delete them.
- 'The module includes one line with the description of the crontab entry C("#Ansible: <name>")
corresponding to the "name" passed to the module, which is used by future ansible/module calls
to find/check the state.'
version_added: "0.9"
options:
name:
description:
- Description of a crontab entry.
required: false
default: null
user:
description:
- The specific user who's crontab should be modified.
required: false
default: root
job:
description:
- The command to execute. Required if state=present.
required: false
default: null
state:
description:
- Whether to ensure the job is present or absent.
required: false
default: present
choices: [ "present", "absent" ]
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
minute:
description:
- Minute when the job should run ( 0-59, *, */2, etc )
required: false
default: "*"
hour:
description:
- Hour when the job should run ( 0-23, *, */2, etc )
required: false
default: "*"
day:
description:
- Day of the month the job should run ( 1-31, *, */2, etc )
required: false
default: "*"
aliases: [ "dom" ]
month:
description:
- Month of the year the job should run ( 1-12, *, */2, etc )
required: false
default: "*"
weekday:
description:
- Day of the week that the job should run ( 0-7 for Sunday - Saturday, *, etc )
required: false
default: "*"
aliases: [ "dow" ]
reboot:
description:
- If the job should be run at reboot. This option is deprecated. Users should use special_time.
version_added: "1.0"
required: false
default: "no"
choices: [ "yes", "no" ]
special_time:
description:
- Special time specification nickname.
version_added: "1.3"
required: false
default: null
choices: [ "reboot", "yearly", "annually", "monthly", "weekly", "daily", "hourly" ]
requirements:
- cron
author: Dane Summers
updates: Mike Grozak
"""
EXAMPLES = '''
# Ensure a job that runs at 2 and 5 exists.
# Creates an entry like "* 5,2 * * ls -alh > /dev/null"
- cron: name="check dirs" hour="5,2" job="ls -alh > /dev/null"
# Ensure an old job is no longer present. Removes any job that is prefixed
# by "#Ansible: an old job" from the crontab
- cron: name="an old job" state=absent
# Creates an entry like "@reboot /some/job.sh"
- cron: name="a job for reboot" special_time=reboot job="/some/job.sh"
# Creates a cron file under /etc/cron.d
- cron: name="yum autoupdate" weekday="2" minute=0 hour=12
user="root" job="YUMINTERACTIVE=0 /usr/sbin/yum-autoupdate"
cron_file=ansible_yum-autoupdate
# Removes a cron file from under /etc/cron.d
- cron: cron_file=ansible_yum-autoupdate state=absent
'''
import os
import re
import tempfile
CRONCMD = "/usr/bin/crontab"
class CronTabError(Exception):
pass
class CronTab(object):
"""
CronTab object to write time based crontab file
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
self.root = (os.getuid() == 0)
self.lines = None
self.ansible = "#Ansible: "
# select whether we dump additional debug info through syslog
self.syslogging = False
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 as e:
# cron file does not exist
return
except:
raise CronTabError("Unexpected error:", sys.exc_info()[0])
else:
(rc, out, err) = self.module.run_command(self._read_user_execute())
if rc != 0 and rc != 1: # 1 can mean that there are no jobs.
raise CronTabError("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):
if self.syslogging:
syslog.syslog(syslog.LOG_NOTICE, 'ansible: "%s"' % message)
def is_empty(self):
if len(self.lines) == 0:
return True
else:
return False
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:
# os.system(self._write_execute(path))
(rc, out, err) = self.module.run_command(self._write_execute(path))
os.unlink(path)
if rc != 0:
self.module.fail_json(msg=err)
def add_job(self, name, job):
# Add the comment
self.lines.append("%s%s" % (self.ansible, name))
# Add the job
self.lines.append("%s" % (job))
def update_job(self, name, job):
return self._update_job(name, job, self.do_add_job)
def do_add_job(self, lines, comment, job):
lines.append(comment)
lines.append("%s" % (job))
def remove_job(self, name):
return self._update_job(name, "", self.do_remove_job)
def do_remove_job(self, lines, comment, job):
return None
def remove_job_file(self):
try:
os.unlink(self.cron_file)
except OSError as e:
# cron file does not exist
return
except:
raise CronTabError("Unexpected error:", sys.exc_info()[0])
def find_job(self, name):
comment = None
for l in self.lines:
if comment is not None:
if comment == name:
return [comment, l]
else:
comment = None
elif re.match( r'%s' % self.ansible, l):
comment = re.sub( r'%s' % self.ansible, '', l)
return []
def get_cron_job(self,minute,hour,day,month,weekday,job,special):
if special:
if self.cron_file:
return "@%s %s %s" % (special, self.user, job)
else:
return "@%s %s" % (special, job)
else:
if self.cron_file:
return "%s %s %s %s %s %s %s" % (minute,hour,day,month,weekday,self.user,job)
else:
return "%s %s %s %s %s %s" % (minute,hour,day,month,weekday,job)
return None
def get_jobnames(self):
jobnames = []
for l in self.lines:
if re.match( r'%s' % self.ansible, l):
jobnames.append(re.sub( r'%s' % self.ansible, '', l))
return jobnames
def _update_job(self, name, job, addlinesfunction):
ansiblename = "%s%s" % (self.ansible, name)
newlines = []
comment = None
for l in self.lines:
if comment is not None:
addlinesfunction(newlines, comment, job)
comment = None
elif l == ansiblename:
comment = l
else:
newlines.append(l)
self.lines = newlines
if len(newlines) == 0:
return True
else:
return False # TODO add some more error testing
def render(self):
"""
Render this crontab as it would be in the crontab.
"""
crons = []
for cron in self.lines:
crons.append(cron)
result = '\n'.join(crons)
if result and result[-1] not in ['\n', '\r']:
result += '\n'
return result
def _read_file_execute(self):
"""
Returns the command line for reading a crontab
"""
return "%s -l%s" % (CRONCMD, self._user_execute())
def _read_user_execute(self):
"""
Returns the command line for reading a crontab
"""
return "%s -l %s" % (CRONCMD, self._user_execute())
def _write_execute(self, path):
"""
Return the command line for writing a crontab
"""
return "%s %s %s" % (CRONCMD, path, self._user_execute())
def _user_execute(self):
"""
User command switches to append to the read and write commands.
"""
if self.user:
return "%s %s" % (' -u ', str(self.user))
return ''
#==================================================
def main():
# The following example playbooks:
#
# - cron: name="check dirs" hour="5,2" job="ls -alh > /dev/null"
#
# - name: do the job
# cron: name="do the job" hour="5,2" job="/some/dir/job.sh"
#
# - name: no job
# cron: name="an old job" state=absent
#
# Would produce:
# # Ansible: check dirs
# * * 5,2 * * ls -alh > /dev/null
# # Ansible: do the job
# * * 5,2 * * /some/dir/job.sh
module = AnsibleModule(
argument_spec = dict(
name=dict(required=False),
user=dict(required=False),
job=dict(required=False),
cron_file=dict(required=False),
state=dict(default='present', choices=['present', 'absent']),
backup=dict(default=False, type='bool'),
minute=dict(default='*'),
hour=dict(default='*'),
day=dict(aliases=['dom'], default='*'),
month=dict(default='*'),
weekday=dict(aliases=['dow'], default='*'),
reboot=dict(required=False, default=False, type='bool'),
special_time=dict(required=False,
default=None,
choices=["reboot", "yearly", "annually", "monthly", "weekly", "daily", "hourly"],
type='str')
),
supports_check_mode = False,
)
name = module.params['name']
user = module.params['user']
job = module.params['job']
cron_file = module.params['cron_file']
state = module.params['state']
backup = module.params['backup']
minute = module.params['minute']
hour = module.params['hour']
day = module.params['day']
month = module.params['month']
weekday = module.params['weekday']
reboot = module.params['reboot']
special_time = module.params['special_time']
do_install = state == 'present'
changed = False
res_args = dict()
crontab = CronTab(module, user, cron_file)
if crontab.syslogging:
syslog.openlog('ansible-%s' % os.path.basename(__file__))
syslog.syslog(syslog.LOG_NOTICE, 'cron instantiated - name: "%s"' % name)
# --- user input validation ---
if (special_time or reboot) and \
(True in [(x != '*') for x in [minute, hour, day, month, weekday]]):
module.fail_json(msg="You must specify time and date fields or special time.")
if cron_file and do_install:
if not user:
module.fail_json(msg="To use file=... parameter you must specify user=... as well")
if reboot and special_time:
module.fail_json(msg="reboot and special_time are mutually exclusive")
if name is None and do_install:
module.fail_json(msg="You must specify 'name' to install a new cron job")
if job is None and do_install:
module.fail_json(msg="You must specify 'job' to install a new cron job")
if reboot:
if special_time:
module.fail_json(msg="reboot and special_time are mutually exclusive")
else:
special_time = "reboot"
# if requested make a backup before making a change
if backup:
(backuph, backup_file) = tempfile.mkstemp(prefix='crontab')
crontab.write(backup_file)
if crontab.cron_file and not do_install:
crontab.remove_job_file()
changed = True
module.exit_json(changed=changed,cron_file=cron_file,state=state)
job = crontab.get_cron_job(minute, hour, day, month, weekday, job, special_time)
old_job = crontab.find_job(name)
if do_install:
if len(old_job) == 0:
crontab.add_job(name, job)
changed = True
if len(old_job) > 0 and old_job[1] != job:
crontab.update_job(name, job)
changed = True
else:
if len(old_job) > 0:
crontab.remove_job(name)
changed = True
res_args = dict(
jobs = crontab.get_jobnames(), changed = changed
)
if changed:
crontab.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 cron task.")
# include magic from lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()
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