How to Make the Python Program to Check Linux Services

Python code to check if service is running or not.?

Simply by using os.system(). You then get the return code of the execution; 0 means running, 768 stopped

>>> import os
>>> stat = os.system('service sshd status')
Redirecting to /bin/systemctl status  sshd.service
● sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
   Active: active (running) since Thu 2017-10-05 09:35:14 IDT; 29s ago
     Docs: man:sshd(8)
           man:sshd_config(5)
  Process: 620 ExecStart=/usr/sbin/sshd $OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 634 (sshd)
   CGroup: /system.slice/sshd.service
           └─634 /usr/sbin/sshd
>>> stat
0  <--  means service is running

>>> os.system('service sshd stop')
Redirecting to /bin/systemctl stop  sshd.service
0  <-- command succeeded

>>> os.system('service sshd status')
Redirecting to /bin/systemctl status  sshd.service
● sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since Thu 2017-10-05 09:41:58 IDT; 10s ago
     Docs: man:sshd(8)
...
768 <-- service not running

The return code is the one returned from the execution. From the service manpage:

EXIT CODES
service calls the init script and returns the status returned by it.

So it's up to the init script executed. You can safely say any return code other than 0 means the service is not running.

You can either check if the process is running instead using:

>>> os.system('ps aux | grep sshd | grep -v grep | wc -l')
2
>>> os.system('ps aux | grep sshd123 | grep -v grep | wc -l')
0

Need a hand with this script to check service status

Using os.system() only give you back the error code of the command, not the result of the command. As stated in the documentation for os.system(), you should look into using the subprocess module for running OS commands and retrieving the results of them.

import subprocess
check = subprocess.run(["systemctl", "is-active", "webmin"], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
if check.stdout == b"active":  # Your result may end in a newline: b"active\n"
    print("Webmin is active!")

how to check service running on other server with python

You can use the following code for your service. i think these codes will help you
in your problem.

            ip = your_ip
            server_user = your_serviceuser
            server_pass = your_pass
            command = f"net use \\\\{ip} {server_pass} /USER:{server_user}"
            os.system(command)
            command = f"SC \\\\{ip} query SQLSERVERAGENT"
            process = subprocess.Popen(command, stdout=subprocess.PIPE)
            output, err = process.communicate()
            
            output = str(str(str(str(output)[2:-1].replace(' ', '')).replace('\\t', '')).replace('\\r', '')).split('\\n')
            if output[3] != 'STATE:4RUNNING':
                print("service is running...")

How to display list of running processes Python?

Try this command:

ps -ef | grep python

ps stands for process status

How to make a Python script run like a service or daemon in Linux

You have two options here.

1. Make a proper cron job that calls your script. Cron is a common name for a GNU/Linux daemon that periodically launches scripts according to a schedule you set. You add your script into a crontab or place a symlink to it into a special directory and the daemon handles the job of launching it in the background. You can read more at Wikipedia. There is a variety of different cron daemons, but your GNU/Linux system should have it already installed.

2. Use some kind of python approach (a library, for example) for your script to be able to daemonize itself. Yes, it will require a simple event loop (where your events are timer triggering, possibly, provided by sleep function).

I wouldn't recommend you to choose 2., because you would be, in fact, repeating cron functionality. The Linux system paradigm is to let multiple simple tools interact and solve your problems. Unless there are additional reasons why you should make a daemon (in addition to trigger periodically), choose the other approach.

Also, if you use daemonize with a loop and a crash happens, no one will check the mail after that (as pointed out by Ivan Nevostruev in comments to this answer). While if the script is added as a cron job, it will just trigger again.

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