The following instructions will allow to run cronjobs in a Docker container using nginx, php 7.2 and Symfony. In order to run multiple services in a container, we'll use supervisord.

Make sure you have Docker installed in your system.

After cloning this repository we can build the docker container by using

docker-compose -f docker.dev.yml up --build 

Check the cronjob file content

docker exec -ti cron_docker_php cat /etc/cron.d/cronjobs 

The Symfony Command used for this cron can be found at www/src/Command/SayHelloCommand

By default there's a cronjob that will print a message in a log file every minute. We can check the log

docker exec -ti cron_docker_php cat /var/log/cron.log 

We'll be using docker exec to connect with the running container

docker exec -ti cron_docker_php bash 

The file it's placed next to Dockerfile at

docker/php/cronjobs

You can add as many cron jobs as you want. Make sure the php path is right by using which php inside the running container and you leave and empty line after the last cronjob

In this file we'll find all the related actions commented

We can test our web app via http://localhost:8080 is also working