Ansible docker module: expose multiple <IPv4>:<port>:<port> combos at once

[Walter Dolce]

Hello Ansiblers!

I was trying to think of a way to expose multiple ports in a row by using the docker module (http://docs.ansible.com/ansible/docker_module.html) but I can't think of anything except looping through the values I would need by means of the usual with_items way, which is not what I want because it would result in an overwrite of the previous iteration.

My scenario is as follows:

tasks:

  - name: Install Nginx container

    docker:
      name: webserver_nginx
      image: nginx
      state: reloaded
      expose:
        - "{{ ansible_docker0.ipv4.address }}:80:80"
      ports:
        - "{{ ansible_docker0.ipv4.address }}:80:80"

But what I want would be something like:

tasks:

  - name: Install Nginx container

    docker:
      name: webserver_nginx
      image: nginx
      state: reloaded
      expose:
        - "{{ ansible_docker0.ipv4.address }}:80:80"

        - "{{ ansible_eth0.ipv4.address }}:80:80"
        - "{{ ansible_eth1.ipv4.address }}:80:80"

      ports:
        - "{{ ansible_docker0.ipv4.address }}:80:80"

        - "{{ ansible_eth0.ipv4.address }}:80:80"
        - "{{ ansible_eth1.ipv4.address }}:80:80"

Now, I know that the number of network interfaces is something that could change at some point, I was thinking to loop over the ansible_interfaces and dynamically get the ansible_{{interface}}.ipv4.address if any. But the problem remains: I would end up using a loop and running the task multiple times with a single expose/ports definition overwriting the previous ones.

Did anyone encounter this scenario so far?

How could I specify multiple expose/ports combos at once by dynamically grab the ansible_{{interface}}.ipv4.address items?

Thanks!

[Walter Dolce]

I found a solution for now. I quickly wrote a filter plugin to obtain what I wanted - https://gist.github.com/walterdolce/93a89018d69392de7c94bf690b761455

The final product for now is:

tasks:
   - name: Install Nginx container
     docker:
       name: webserver_nginx
       image: nginx
       state: reloaded

       expose: "{{ ansible_all_ipv4_addresses | map_ipv4_port_exports(container_port='80', host_port='80') }}"
       ports: "{{ ansible_all_ipv4_addresses | map_ipv4_port_exports(container_port='80', host_port='80') }}"

I could probably change the name of the filter to make it more docker specific.

Any feedback is more than welcome!