Read sensor data from python

fans.py

""" Takes output from "sensors" command and writes it to 
a file by default. Can also connect to Redis and Influxdb
"""

#!/usr/bin/python

import subprocess
import json
from datetime import datetime
from traceback import print_exc

# you can install these modules with pip if needed
try:
  import redis
  REDIS_CONNECTION = redis.StrictRedis(host='localhost', port=6379, db=0)
except ImportError:
  pass

try:
  from influxdb import InfluxDBClient
  INFLUX_CLIENT = InfluxDBClient('localhost', 8086, 'USERNAME', 'PASSWORD', 'DATABASE')
except ImportError:
  pass

IGNORE_FANS = ['fan1', 'fan3', 'fan4', 'fan5']
DATA_FILE_LOCATION = '/tmp/fan_speeds.json'

# make True to update a influxdb server
USE_INFLUX = False

# make True to update a redis server
USE_REDIS = False


def fetch_sensor_data():

    try:
        proc = subprocess.Popen(['sensors'], stdout=subprocess.PIPE,
                                close_fds=True)
        results = proc.communicate()[0]
        fans = {}

        for line in results.split("\n"):
            fan = fetch_fan(line)
            if fan:
                fans[fan.get('name', 'NO_NAME')] = float(fan.get('value', 0))

        for fan, speed in fans.iteritems():
            print("{0} currently at {1}RPM".format(fan, speed))

        write_data_file(fans)

        if USE_REDIS:
            write_data_redis(fans)

        if USE_INFLUX:
            write_data_influx(fans)

    except Exception as exception:
        print_exc()
        print("Failed to get sensor data: {0}".format(exception.message))


def write_data_influx(fans):
    json_payload = []
    time = datetime.now().strftime("%Y-%m-%dT%H:%M:%S")
    try:
        for fan, speed in fans.iteritems():
            payload = {
                "measurement": fan,
                "tags": {
                    "host": "jarvis",
                    "location": "garage"
                },
                "time": time,
                "fields": {
                    "value": speed
                }
            }
            json_payload.append(payload)
        INFLUX_CLIENT.write_points(json_payload)
    except Exception as exception:
        print_exc()
        print("Failed to write to Influx. Error {}".format(exception.message))


def write_data_redis(fans):
    try:
        for fan, speed in fans.iteritems():
            REDIS_CONNECTION.set(fan, speed)
    except Exception as exception:
        print_exc()
        print("Failed to write to Redis. Error {}".format(exception.message))


def write_data_file(fans):
    try:
        fans['time'] = datetime.now().strftime("%Y-%m-%dT%H:%M:%S")
        with open(DATA_FILE_LOCATION, 'w') as fan_speed_file:
            fan_speed_json = fan_speed_file.write(json.dumps(fans))
            fan_speed_file.close()
    except Exception as exception:
        print_exc()
        print("Failed to write to data file. Error {}".format(
            exception.message))


def fetch_fan(line):
    if not line.startswith('fan'):
        return False

    result = {}

    try:
        name, speed = line.split(':')

        if name not in IGNORE_FANS:
            result['name'] = name
            result['value'] = speed.split('RPM')[0].strip()
    except Exception as exception:
        print_exc()
        print ("Failed to get fan data from sensor output")
        return False
    return result

if __name__ == "__main__":
    fetch_sensor_data()