Bash – Run while true in systemd script

bashshell-scriptsystemd

I got a bash script essentially runnning this:

#!/bin/bash

[...]

 while true; do
         str="broadcast "`randArrayElement "messages[@]"`
         server_send_message $str
         sleep $interval
 done

Now I want to run this as a systemd service, my service script looks like this:

[Unit]
Description=Announcer
After=network.target

[Service]
ExecStart=/usr/local/bin/somescript &; disown
ExecStop=/usr/bin/kill -9 `cat /tmp/somescript.pid`
Type=forking
PIDFile=/tmp/somescript.pid

[Install]
WantedBy=default.target

Unfortunately when I run this service via service somescript start it is working but because of the while true loop my terminal is stuck in starting the script:

● somescript.service - somescript service
   Loaded: loaded (/etc/systemd/system/somescript.service; disabled; vendor preset: enabled)
   Active: activating (start) since Wed 2016-08-17 12:22:34 CEST; 43s ago
  Control: 17395 (somescript)
   CGroup: /system.slice/somescript.service
           ├─17395 /bin/bash /usr/local/bin/somescript &; disown
           └─17409 sleep 600

How can I run this script as a service without being stuck in "starting" / the while true loop?

Best Answer

You need to let systemd work for you. Let it handle the forking at the start and the killing of the process. Eg replace your service part by

[Service]
Type=simple
ExecStart=/usr/local/bin/somescript
PIDFile=/tmp/somescript.pid

then you can use systemctl start, status and stop. You must remember that the lines in systemd are NOT interpreted by the shell, so for example your &; is merely passed as another parameter of 2 characters to your script.

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