Managing infra variables in the inventory

Global variables

Variables that are used by convention accross roles:


Role variables

Base variable are defined in playlabs/roles/rolename/vars/main.yml and start with the rolename_, they can be overridden in your inventory’s group_vars/all/rolename.yml.

The base variable will default to the same variable without the rolename_ prefix:

# Set project_image project role variable from the command line

Role structure

Default roles live in playlabs/roles and share the standard directory structure with ansible roles, that you can scaffold with the ansible-galaxy tool.

Playlabs use roles as alternatives as docker-compose when possible, rather than polluting the host with many services.

Project variables

The project role base variables calculate to be overridable by prefix/instance:

# project_{image,*} base value references project_staging_{image,*} from inventory

# project_{image,*} base value references mrs_production_{image,*} from inventory
instance=production prefix=mrs

Project plugins variable

The project role has a special plugins variable that can be overridden in the usual way, but it will also try to find it by introspecting the docker image for the PLAYLABS_PLUGINS env var ie:

ENV PLAYLABS_PLUGINS postgres,django,uwsgi,sentry

Plugin variables

Plugin variables are loaded by the project role for each plugin that it loads if any.

Base plugin variables start with project_pluginname_ and the special project_pluginname_env variable should be a dict, they will be all merged to add environment variables to the project container, project_env will be a merge of all them plugin envs.

Plugin env vars should preferably use overridable variables.