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#!/usr/bin/python
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# This module creates a list of cron intervals for a node in a group of nodes
# to ensure each node runs a cron in round robbin style.
from __future__ import print_function
import argparse
import json
import sys
MINUTE_SPAN = 1
HOUR_SPAN = 60
DAY_SPAN = 24 * HOUR_SPAN
WEEK_SPAN = 7 * DAY_SPAN
def json_exit(msg=None, failed=False, changed=False):
if type(msg) is not dict:
msg = {'msg': str(msg)}
msg.update({'failed': failed, 'changed': changed})
print(json.dumps(msg))
sys.exit()
def generate(host_index, total_hosts, total_rotation_mins):
min = '*'
hour = '*'
day = '*'
crons = []
if host_index >= total_hosts:
return crons
rotation_frequency = total_rotation_mins // total_hosts
cron_min = rotation_frequency * host_index
# Build crons for a week period
if total_rotation_mins == WEEK_SPAN:
day = cron_min // DAY_SPAN
hour = (cron_min % DAY_SPAN) // HOUR_SPAN
min = cron_min % HOUR_SPAN
crons.append({'min': min, 'hour': hour, 'day': day})
# Build crons for a day period
elif total_rotation_mins == DAY_SPAN:
hour = cron_min // HOUR_SPAN
min = cron_min % HOUR_SPAN
crons.append({'min': min, 'hour': hour, 'day': day})
# Build crons for multiple of an hour
elif total_rotation_mins % HOUR_SPAN == 0:
for multiple in range(1, DAY_SPAN // total_rotation_mins + 1):
time = cron_min
if multiple > 1:
time += total_rotation_mins * (multiple - 1)
hour = time // HOUR_SPAN
min = time % HOUR_SPAN
crons.append({'min': min, 'hour': hour, 'day': day})
# Build crons for multiple of a minute
elif total_rotation_mins % MINUTE_SPAN == 0:
for multiple in range(1, HOUR_SPAN // total_rotation_mins + 1):
time = cron_min
if multiple > 1:
time += total_rotation_mins * (multiple - 1)
min = time // MINUTE_SPAN
crons.append({'min': min, 'hour': hour, 'day': day})
return crons
def main():
parser = argparse.ArgumentParser(description='''Creates a list of cron
intervals for a node in a group of nodes to ensure each node runs
a cron in round robbin style.''')
parser.add_argument('-t', '--time',
help='Time in seconds for a token rotation cycle',
required=True,
type=int)
parser.add_argument('-i', '--index',
help='Index of host starting from 0',
required=True,
type=int)
parser.add_argument('-n', '--number',
help='Number of tokens that should exist',
required=True,
type=int)
args = parser.parse_args()
json_exit({'cron_jobs': generate(args.index, args.number, args.time)})
if __name__ == "__main__":
main()
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