Simple Cron

alpine3.10.0 - 5 MB ubuntu18.04 - 49 MB

This image is designed to help setting up a cron container alot easier. You will have crontab available out of the box. And you will be able to implement cronjob/cronjobs in two different ways when using this image.

So what you need to do

One of two things:

NOTE:

We will be using docker-compose.yml to setup the image for build

Docker-compose.yml EXAMPLE file wich includes all options for setup, where you DONT need any packages installed to run the cronjobs:

(In this case only the cronjobs inside of the volume containing a text with the cronjobs will be used, if you leave the volume out, the environment variable will be used instead)

version: '3'

services:
  cron:
    image: thezochko/simple-cron:alpine3.10.0
    environment:
      CRONJOB: "* * * * * echo 'hey' >> /test.txt"
    volumes:
      - "./docker/docker-entrypoint-initcron.d:/docker-entrypoint-initcron.d/"

Docker-compose.yml EXAMPLE file wich includes all options for setup, where you DO need packages installed to run the cronjobs:

(In this case only the cronjobs inside of the volume containing a text with the cronjobs will be used, if you leave the volume out, the environment variable will be used instead)

version: '3'

services:
  cron:
    build:
        context: .
        dockerfile: Dockerfile
    environment:
      CRONJOB: "* * * * * echo 'hey' >> /test.txt"
    volumes:
      - "./docker/docker-entrypoint-initcron.d:/docker-entrypoint-initcron.d/"

When using this approach you will have to define your own Dockerfile (descripted below) wich extends the base image of your choice.

1 .

Create a volume with the name of "docker-entrypoint-initcron.d/" on your container site

volumes:
      - "./docker-entrypoint-initcron.d:/docker-entrypoint-initcron.d/"

What you call it on the host site we dont care about. But we need to have a file "cronjobs.txt" (or whatever you call it) where all of your cronjobs are listed.

* * * * echo "example cronjob" >> /cronjob_lob1.txt 2>&1
* * * * echo "example cronjob" >> /cronjob_lob2.txt 2>&1
* * * * echo "example cronjob" >> /cronjob_lob3.txt 2>&1

2 .

You only need one cronjob running inside of the container? Then provide enviornment variable:

environment:
    CRONJOB: '* * * * * echo "example cronjob" >> /cronjob_lob.txt 2>&1'

Now you have cronjob or cronjobs running inside of your container.

Remember that the container needs to have access to the directory where it shuold work. If you have a website located inside another container you would have to create a volume that both containers have access to.

environment:
      CRONJOB: * * * * * php /var/www/public_html/cronfile.php >> /dev/null 2>&1
volumes:
      - "./public_html:/var/www/public_html"

NOTICE

Your container needs to have all packages installed, on wich each cronjob depends on in order to work.

Example could be Laravel standard cron:

environment:
    CRONJOB: '* * * * * cd /path-to-your-project && php artisan schedule:run >> /dev/null 2>&1'

If you use that, you need to have all of the packages that laravel needs in order to execute the cron command.

Laravel dependencies

To do so, you simply create your own Dockerfile and install the packages alpine3.10.0 Dockerfile example:

FROM thezochko/simple-cron:alpine3.10.0

RUN apk update && apk add --no-cache \
php7 \
php7-pdo_mysql \
php7-curl \
php7-json \
php7-session \
php7-bcmath \
php7-ctype \
php7-mbstring \
php7-openssl \
php7-tokenizer \
php7-xml

ubuntu18.04 Dockerfile example:

FROM thezochko/simple-cron:ubuntu18.04

RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
php7 \
php7-curl \
php7-mysqli \
php7-json