[Pro] Allow new molecule format for Docker driver

[rockandska]

Proposal:

Author: RockAndSka <@rockandska> IRC: RockAndSka

Date: 2019-04-10

• Status: New
• Proposal type: core design
• Estimated time to implement: more or less 3 days (without the docs)

Motivation

• Allowing users to be able to have access to the full docker modules used by molecule and avoid many issues / PR related to modules arguments missing.
• Avoid repetition for platforms common options (images build arg, docker host settings etc..)

Problems

What problems exist that this proposal will solve?

• [docker_network] Allow more options #1879
• Docker driver doesn't support etc_hosts from docker_container module #1878
• Use provisioner name as Docker container name #1847
• Docker driver: create.yml jinja expression always evaulates to True #1688
• #1817
• Added docker-machine support #1920
• Add user arg for docker driver #1889

and many others

Solution proposal

All modules used are in a unique dict avoiding to pass to the modules the "args" key with a dict of the options.
Allowing a new molecule format for docker driver (compatible with the old version too) will let the users been able to use all the args available for modules (docker_network, docker_image,docker_container)

A working example is provided here: rockandska/repro-issues

Dependencies (optional)

None

Testing (optional)

A little test is provided in my repo but need to be more tested with different cases already tested.

Documentation (optional)

Will be provide in case this proposal is accept and the format well defined and validated

Anything else?

Any comments , questions are welcome and could be discuss on IRC too if needed

Edit:

• many jinja kung-fu could be avoid by writing some libraries but didn't done it since it is a POC
• didn't done it too, but will be better if new and old create/destroy yaml are separate in sub_playbooks and import by create/destroy depending on the schema version to avoid the "skipped" tasks
• the warnings triggered by the usage of passing a dict as args to the modules could be avoid by adding "INJECT_FACTS_AS_VARS=false" (ansible>=2.5) only for the create/destroy "ansible-playbook" commands. (having it for other tasks have too many implications)

[MarkusTeufelberger]

Related (one possible solution to the current design): #1642