gps-tracker.py

#!/usr/bin/env python3

'''
https://raspberry.tips/projekte/gps-tracking-mit-dem-raspberry-pi
'''

from subprocess import call, PIPE
from time import sleep
from datetime import datetime as dt
from pathlib import Path
import logging


logging.basicConfig()
logger = logging.getLogger(__file__)


def terminate():
    '''
    Terminate existing gpsd instances and
    start gpsd and sleep a few seconds
    '''
    ret_val1 = call(['sudo', 'killall', 'gpsd'], stderr=PIPE, stdout=PIPE)
    ret_val2 = call(['sudo', '/usr/sbin/gpsd', '/dev/ttyAMA0', '-F', '/var/run/gpsd.sock'], stderr=PIPE, stdout=PIPE)
    if ret_val1 or ret_val2:
        raise Exception('Could not kill gpsd or start gpsd')
    sleep(30)


def refresh_time():
    '''
    Refresh the local time
    '''
    call(['sudo', 'service', 'ntp', 'restart'])
    sleep(3)


def make_filename():
    '''
    output file name with actual date
    '''
    now = dt.now().replace(microsecond=0).isoformat()
    return Path('/home/pi/') / (now + '-gps_track')


def start():
    '''
    start gpspipe and output
    the GPS Data as NMEA to file
    '''
    filename = make_filename()
    call(['gpspipe', '-d', '-l', '-r', '-o', filename], stderr=PIPE, stdout=PIPE)


if __name__ == '__main__':
    logger.setLevel(logging.INFO)
    exc = lambda err: logger.critical(err)
    try:
        logger.info('Terminating process')
        terminate()
    except Exception as err:
        exc(err)
    try:
        logger.info('Refreshing time')
        refresh_time()
    except Exception as err:
        exc(err)
    try:
        logger.info('Start reading process')
        start()
    except Exception as err:
        exc(err)