HOW TO RUN A SCRIPT AS A SERVICE IN RASPBERRY PI – RASPBIAN JESSIE: The Raspberry Pi is an incredible popular credit card size mini computer with awesome capabilities. Despite of is mini size it behaves pretty much like a regular computer (it has an OS with a graphical interface, an ethernet port so you can surf the web, an HDMI output, etc.) but also it exposes several inputs/outputs (GPIO) to interact with the real world (sensors and cool tech gadgets).
A pretty common task when using this device, is to run some script (for example a python script) as a service in the operating system so it can start on boot, stop and restart using systemctl and more. In this post I’m going to explain how to set a little script as a service using Raspbian Jessie in a Raspberry Pi.
First of all, we are going to write a small python script which print “Hello World” every 60 seconds. This is going to be our service script (hello_world.py):
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#!/usr/bin/python from time import sleep try: while True: print "Hello World" sleep(60) except KeyboardInterrupt, e: logging.info("Stopping...") |
You can execute it by python hello_world.py. If you get boring reading so many hello worlds, press Ctrl+C (or Cmd+C on OSX) to stop it. Save this file as hello_world.py in your home folder (home/pi/). Now we’re going to define the service to run this script:
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cd /lib/systemd/system/ sudo nano hello.service |
The service definition must be on the /lib/systemd/system folder. Our service is going to be called “hello.service”:
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[Unit] Description=Hello World After=multi-user.target [Service] Type=simple ExecStart=/usr/bin/python /home/pi/hello_world.py Restart=on-abort [Install] WantedBy=multi-user.target |
means is aborted is going to be restarted automatically. You can check more on service’s options in the next wiki: https://wiki.archlinux.org/index.php/systemd.
Now that we have our service we need to activate it:
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sudo chmod 644 /lib/systemd/system/hello.service chmod +x /home/pi/hello_world.py sudo systemctl daemon-reload sudo systemctl enable hello.service sudo systemctl start hello.service |
For every change that we do on the /lib/systemd/system folder we need to execute a daemon-reload (third line of previous code). If we want to check the status of our service, you can execute:
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sudo systemctl status hello.service |
In general:
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# Check status sudo systemctl status hello.service # Start service sudo systemctl start hello.service # Stop service sudo systemctl stop hello.service # Check service's log sudo journalctl -f -u hello.service |
