Add support to install Docker Ansible module dependencies

[ndusart]

Ansible docker_container module requires that either docker or docker-py python library is installed in order to work.

I think this would be a good thing to install these from this role as this is always required for use in dependent roles. Maybe through a variable to enable that ?

[haxorof]

Thanks for the suggestion @ndusart. I have actually been thinking about this from time to time but has hesitated a bit because of incompatibilities in docker-py etc and what to use to install it: pip or OS package manager. Want to have an easy config so users does not need to think too much. 😄

Question: when you install Ansible do you use pip or OS pkg mgr? If you use pip, do you use virtualenv?

Cheers!

[ndusart]

I totally understand your concern.

I am not quite into python development and not very used with the pip package manager and all that stuff so I maybe overlooked the complexity of it for a broad compatibility.

I simply do this on my playbooks:

- name: Ensure pip is installed
  package:
    name: python-pip
    state: present

- name: Ensure docker library for python is installed
  pip:
    name: docker
    state: present

For your question about the installation of Ansible, I'm using a local clone of their git repository and use the hacking/env_setup script to define environment variables to use it. But I'm not installing it on the remote host, so I do not know if it has an implication in this issue.

Maybe a boolean role variable to opt-in on this feature with other variables letting the user define which docker python sdk to install and how, with default values that are likely to fit most of the people ?
Complex cases could be left to be dealt outside this role (with direct commands to docker for example)

[haxorof]

As you say I see this as an opt-in feature to ease use of docker module in Ansible. Hopefully the packages are called the same in the different distributions this role supports and might be a good also to have a variable to say if pip shall be used or not because mixing pip and stuff from the apt/yum/dnf then you can get into trouble with dependency problems.

Hopefully I will take a deeper look into it later this week.

[haxorof]

@ndusart I have now implemented that I hope is what you are looking for.

If you can please try it out on the master before I do a release if you can and if you got some feedback please let me know. 😄

These are the variables you can use to get dependencies:

# Ensures 'docker_container' Ansible module dependencies are installed
docker_container_deps: false
# Ensures 'docker_service' Ansible module dependencies are installed
docker_service_deps: false
# Ensures 'docker_stack' Ansible module dependencies are installed
docker_stack_deps: false

Cheers!

[haxorof]

Example to use it can be found here: https://github.com/haxorof/ansible-role-docker-ce/blob/master/tests/test_postinstall.yml

[ndusart]

@haxorof sorry about the delay, I was quite busy these days.

I just tested it with success in my playbooks ! 😃
I could only test docker_container and docker_image commands so I cannot say for the others.

Maybe there should be a comment that docker_container_deps installs dependencies for docker_image as well ?
It could lead to confusion imho.

Thanks for the good work ! 👍

[haxorof]

Thanks @ndusart!
I will update the documentation so it will be more clear. Thank you again for testing the parts you need.

Will do a release today if I got time to update the documentation.

Cheers!

[haxorof]

btw, would you @ndusart have some suggestion for better variable names for this? Was looking through the Ansible docs and maybe change to something like docker_core_deps and then document what modules it will cover.

Cheers!

[haxorof]

# Ensures dependencies are installed so that most of the 'docker' Ansible modules will work
docker_sdk: false
# Ensures dependencies are installed so that 'docker_service' Ansible module will work
docker_compose: false
# Ensures dependencies are installed so that 'docker_stack' Ansible module will work
docker_stack: false

[ndusart]

The new terms are good to me !