Telegraf Laptop Battery Plugin

  • 11/4/2016
  • One-minute read

Wanted to expand a little on my previous blog post Custom Telegraf Plugin , and decided to do a simple battery monitor. The end result looks something like this:

Screen Shot 2016-04-11 at 5.40.47 PM

I decided to read from the file /sys/class/power_supply/BAT0/capacity on my Ubuntu 14.04 machine, this file merely shows the current battery percent:

# cat /sys/class/power_supply/BAT0/capacity
62

All that is needed is a little Python script for converting this output to JSON, my script outputs like this:

# /battery.py
{"status": "Charging", "capacity": 63}

The code is very basic Python: /battery.py

#!/usr/bin/env python
import json

with open('/sys/class/power_supply/BAT0/capacity') as f:
 capacity = f.read().split('\n')[0]
 capacity = int(capacity)

with open('/sys/class/power_supply/BAT0/status') as f:
 status = f.read().split('\n')[0]

results = dict(capacity=capacity,
 status=status)

print json.dumps(results)

All that is left is to add this script to our Telegraf configuration directory:

# cat /etc/telegraf/telegraf.d/battery.conf
[[inputs.exec]]
 command = "/battery.py"
 data_format = "json"
 name_suffix = "_battery"
 interval = "5s"

And there you have it, a simple battery tracker.

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