To fetch data from different data providers several Python scripts were created to download the data and publish it to the MQTT-broker. In order to consistently fetch new data from different sources cron is utilized to make sure that the scripts are executed and disposed of properly. Each script is a cron job that is executed at a specific time and date. For example, the weather data scripts run every 5 mintues. A crontab holds every task and when it is scheduled to be executed.
Managing the cronjobs
To see the current cronjobs configured you use the following bash-command.
$ crontab -l
To edit or add cronjobs, the following bash-command is used.
$ crontab -e
Checking the status of running cronjobs can be done by the following bash-command.
$ sudo /etc/init.d/cron status
Or,
$ sudo grep CRON /var/log/syslog
Configuring cronjobs
The current configuration of the cronjobs are shown below.
# Edit this file to introduce tasks to be run by cron.
#
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
#
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').#
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
#
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
#
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
#
# For more information see the manual pages of crontab(5) and cron(8)
#
# m h dom mon dow command
*/5 * * * * /usr/bin/python3.7 /home/administrator1/scripts/mi-iot/open-weather-map-scripts/aalesund.py
*/5 * * * * /usr/bin/python3.7 /home/administrator1/scripts/mi-iot/open-weather-map-scripts/trondheim.py
*/5 * * * * /usr/bin/python3.7 /home/administrator1/scripts/mi-iot/open-weather-map-scripts/hareid.py
*/5 * * * * /usr/bin/python3.7 /home/administrator1/scripts/mi-iot/open-weather-map-scripts/festoy.py
*/5 * * * * /usr/bin/python3.7 /home/administrator1/scripts/mi-iot/open-weather-map-scripts/solavaagen.py
*/5 * * * * /usr/bin/python3.7 /home/administrator1/scripts/mi-iot/open-weather-map-scripts/magerholm.py
*/5 * * * * /usr/bin/python3.7 /home/administrator1/scripts/mi-iot/open-weather-map-scripts/sykkylven.py
*/5 * * * * /usr/bin/python3.7 /home/administrator1/scripts/mi-iot/open-weather-map-scripts/sulesund.py
*/15 * * * * /usr/bin/timeout -s SIGTERM 600 /usr/bin/python3.7 /home/administrator1/scripts/mi-iot/buoy-data/XarrayBuoyData.py >> /home/administrator1/Logs.txt 2>&1
12 * * * * /usr/bin/python3.7 /home/administrator1/scripts/mi-iot/simulations/dummy-ferry/ferry-sim.py
