Example for wrapper around ExecStart= for success/failed service notifications

systemd-notify-wrapper.py

#!/usr/bin/python3
# try this for long-running processes:
#
# $ cat example.service
# ...
# Type=simple
# ExecStart=systemd-notify-wrapper.py "/opt/scripts/long-running.sh -a -b FLAG" "%n"
# ...
# 
# send "successful complete" notification if exit code valid
# send "failure" notification otherwise, add "systemctl status example" to notification

import shlex
import subprocess
import sys
import time

cmd = sys.argv[1]
service = sys.argv[2]
rc_valid = [0,]
receivers = "user1,user2".split(",")

start_time = time.time()
proc = subprocess.Popen(shlex.split(cmd), stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
print("proc started, pid %d" % proc.pid)

while proc.poll() is None:
    print(proc.stdout.readline().rstrip().decode("utf-8"))
rc = proc.poll()

delta_time = round(time.time() - start_time, 2)

if delta_time > 3600:
    ts = "%sh" % delta_time/3600
elif delta_time > 60:
    ts = "%sm" % delta_time/60
else:
    ts = "%ss" % delta_time

if rc in rc_valid:
    print("proc done with exit code %d" % rc)
    msg = "service %s complete in %s" % (service, ts)
else:
    print("proc failed with exit code %d" % rc)
    try:
        output = subprocess.check_output(["/bin/systemctl", "status", "-q", service], stderr=subprocess.STDOUT)
    except subprocess.CalledProcessError as err:
        if err.output:
            output = err.output

    msg = """service %s failed in %s

Details:
%s""" % (service, ts, output.decode("utf-8"))

print("send '%s' to '%s'" % (msg, receivers))

exit(rc)