jinja-docker-compose

jinja-docker-compose is a simple python script that wraps docker-compose to provide Jinja2 based templating ability to docker-compose. It is based on 'jinja-compose'.

Dependencies

jinja-docker-compose requires following dependencies to be installed on the system:

• python3
• python3-pip
• Docker engine

Installing

To install the script, simply run:

$ pip install jinja-docker-compose

The script is installed in ~/.local/bin. If not in the PATH add the following to your initiation script, like .bashrc

PATH=~/.local/bin:$PATH

Using jinja-docker-compose

The jinja-docker-compose preprocess the docker-compose file to act upon for instance for loops and conditional statements. The variables used in the preprocessing resides in a dictionnay file in JSON format.

jinja-docker-compose can either just do the pre-processing or as well run docker-compose on the processed file.

Example of dictionary file:

{
  "LOGGING": "false",
  "N_GPU": 2
}

docker-compose file to preprocess:

version: "3"
services:
  {% for i in range(N_GPU) %}
  ubuntu{{i}}:
    image: ubuntu:latest
  {% endfor %}
  ubuntulog:
    image: ubuntu:latest
    {% if LOGGING == 'true' %}
    logging:
      driver: syslog
      options:
        syslog-address: "tcp://graylog.example.com:516"
    {% endif %}

After processing the file looks like this:

version: "3"
services:
  ubuntu1:
    image: ubuntu:latest
  ubuntu2:
    image: ubuntu:latest
  ubuntulog:
    image: ubuntu:latest

The default names of the files are:

File	Default name
Input file to preprocess	docker-compose.yml.j2
Dictionary file	docker-compose.dic
Output file	docker-compose.yml

The options are:

Option	Description
-f	Input file name
-D	Dictionary file name
-o	Output file name
--loader	Uses the FullLoader when loading the YAML, this enables the possible exploit that the FullLoader opens up for.
-r	Apart from genereates the output file, also run docker-compose

All options that are valid options to docker-compose can also be given to jinja-docker-composeand then passed on to docker-compose

Depending on how your system is configured, you may need to run the script with sudo (i.e. if you usually need sudo to run docker, you will need sudo).