Munin plugin that reads any number of DS18B20 temperature sensors using the w1-gpio and w1_therm kernel modules.

ds18b20

#!/usr/bin/env python

import sys
import os
import re
from syslog import syslog

temperatureRegex = r't=(-?\d+)'

sensorNames = {
    '28-00000551b94b': 'Room temperature'
}


def getSensors():
    return [x for x in os.listdir('/sys/bus/w1/devices/') if x.startswith('28-')]


if len(sys.argv) == 2 and sys.argv[1] == "autoconf":
        print "yes"

elif len(sys.argv) == 2 and sys.argv[1] == "config":
        print 'graph_title External temperature sensors'
        print 'graph_vlabel degrees Celsius'
        print 'graph_category sensors'

        for sensor in getSensors():
            if sensor in sensorNames:
                print 'sensor_%s.label %s' % (sensor, sensorNames[sensor])
            else:
                print 'sensor_%s.label %s' % (sensor, sensor)
            print 'sensor_%s.type GAUGE' % (sensor)

else:
    for sensor in getSensors():
        for i in range(3):
            rawData = open('/sys/bus/w1/devices/'+sensor+'/w1_slave', 'r').read()
            syslog('Sensor %s, try %s: %s' % (sensor, i + 1, ' / '.join(rawData.splitlines())))
            if 'YES' in rawData:
                occurences = re.findall(temperatureRegex, rawData)
                if occurences[0] is not None:
                    millidegrees = int(occurences[0])
                    print('sensor_%s.value %s' % (sensor, float(millidegrees) / 1000))
                    break