Script that monitors a service running on systemd. If service is not running the script will try to start the service.

monitor_service.py

#!/bin/python
#
# Copyright 2016 Flavio Garcia
#
# 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.
#
# Usage: monitor_process.py <service_name>
#
# Example(crontab, every 5 minutes): 
# */5 * * * * /root/bin/monitor_service.py prosody > /dev/null 2>&1 
#

import sys
import subprocess


class ServiceMonitor(object):

    def __init__(self, service):
        self.service = service

    def is_active(self):
        """Return True if service is running"""
        cmd = '/bin/systemctl status %s.service' % self.service
        proc = subprocess.Popen(cmd, shell=True,stdout=subprocess.PIPE)
        stdout_list = proc.communicate()[0].split('\n')
        for line in stdout_list:
            if 'Active:' in line:
                if '(running)' in line:
                    return True
        return False

    def start(self):
        cmd = '/bin/systemctl start %s.service' % self.service
        proc = subprocess.Popen(cmd, shell=True,stdout=subprocess.PIPE)
        proc.communicate()

if __name__ == '__main__':
    # TODO: Show usage                                                 
    monitor = ServiceMonitor(sys.argv[1])
    if not monitor.is_active():
        monitor.start()

proc.communicate()[0] returns byte value not string value. Therefore we cannot use .split('\n'). We have to decode it first to string and then use split: proc.communicate()[0].decode("utf-8").split('\n')