Python development [note]: add the python program to the systemctl System Service, pythonsystemctl

Python development [note]: add the python program to the systemctl System Service, pythonsystemctl
Systemctl System Service

Environment: centos7

Details about how to use the systemctl Service

 

Implementation

Normally, we create a file with the. service suffix under the/usr/lib/systemd/system/directory, such as cdr. service.

[Unit]Description=cdrAfter=network.target[Service]ExecStart=/opt/pbx/cdr/cdr.pyType=forking[Install]WantedBy=multi-user.target

Usage:

# Start systemctl start cdr # disable systemctl stop cdr # view status systemctl status cdr # enable auto-start systemctl enable cdr # disable enable auto-start systemctl enable cdr

Normal python programs can be used in this way, but in this case, it is difficult to use the above. servcie file creation method, as shown below:

#!/usr/bin/env python# -*- coding:utf-8 -*-import loggingimport timeimport syslogging.basicConfig(level=logging.INFO)def daemon():    import os    # create - fork 1    try:        pid = os.fork()        if pid > 0:            return pid    except OSError as error:        logging.error('fork #1 failed: %d (%s)' % (error.errno, error.strerror))        return -1    # it separates the son from the father    os.chdir('/opt/pbx')    os.setsid()    os.umask(0)    # create - fork 2    try:        pid = os.fork()        if pid > 0:            return pid    except OSError as error:        logging.error('fork #2 failed: %d (%s)' % (error.errno, error.strerror))        return -1    sys.stdout.flush()    sys.stderr.flush()    si = open("/dev/null", 'r')    so = open("/dev/null", 'a+')    se = open("/dev/null", 'a+')    os.dup2(si.fileno(), sys.stdin.fileno())    os.dup2(so.fileno(), sys.stdout.fileno())    os.dup2(se.fileno(), sys.stderr.fileno())    return 0def main():    pid = daemon()    if pid:        return pid    while True:        logging.info('----------')        time.sleep(1)main()

The biggest difference this time is that a sub-process is fork in the python program. In this case, the first method is difficult. After multiple tests, we found that the following method can achieve our results.

[Unit]Description=lzlAfter=network.target[Service]Type=oneshotRemainAfterExit=yesExecStart=/usr/bin/python3 /home/lzl/workspace/cdrservice/main.py[Install]WantedBy=multi-user.target