HarkTV

Owner	Space
Status	Working
Hostname	harktv.dhcp.nurd.space
Location	Zaal 2
Tool	No
Tool category

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What

Workstation in Zaal 2. It has a barcode scanner which can be used for Partkeepr.

Auto shutdown

We want this machine to shutdown when space is closed. We check MQTT for this in a simple python script. We use paho, so let's install that:

apt-get install python-paho-mqtt

Normally the script would ask for a password to execute the shutdown command. We can avoid this with following line in /etc/sudoers (use visudo for this):

hark harktv =NOPASSWD: /bin/systemctl poweroff

Now we just run a cronjob every 5 minutes:

*/5 * * * * ~/space_status_shutdown.py

The script:

!/usr/bin/env python
2019 The_Niz
checks space status and shuts machine down if space is closed

import paho.mqtt.client as mqtt
import os

The callback for when the client receives a CONNACK response from the server.

def on_connect(client, userdata, flags, rc):

   if rc==0:
       client.connected_flag=True #set flag
       print("Connected with result code "+str(rc))
   else:
       print("Bad connection Returned code=",rc)
   client.subscribe("space/state")

The callback for when a PUBLISH message is received from the server.

def on_message(client, userdata, msg):

   print(msg.topic+" "+str(msg.payload))
   if msg.payload=="False":
       print("Space is uit")
       os.system('sudo /bin/systemctl poweroff')
   else:
       print("Space is aan")
   client.loop_stop()
   client.disconnect()

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message

client.connect("arbiter.vm.nurd.space", 1883, 60) client.loop_forever()