Ansible: Roles, Role Dependencies, and Variables

I just spent some time banging my head against Ansible, and thought I’d share in case anyone else runs across it:

I have a Firefox role that allows you to define a Firefox profile with various plugins, config settings, and the like. And I have a work-from-home (WFH) role that, among other things, sets up a couple of work profiles in Firefox, with certain proxy settings and plugins. I did this the way the documentation says to:

dependencies:
  - name: Profile Work 1
    role: firefox
    vars:
      - profile: work1
        addons:
          - ublock-origin
          - privacy-badger17
          - solarize-fox
        prefs: >-
          network.proxy.http: '"proxy.host.com"'
          network.proxy.http_port: 1234
  - name: Profile Work 2
    role: firefox
    vars:
      - profile: work2
        addons:
          - ublock-origin
          - privacy-badger17
          - solarized-light
        prefs: >-
          network.proxy.http: '"proxy.host.com"'
          network.proxy.http_port: 1234

The WFH stuff worked fine at first, but then I added a new profile.

- name: Roles
  hosts: my-host
  roles:
    - role: wfh
    - role: firefox
      profile: third
      addons:
        - bitwarden-password-manager
        - some fancy-theme

This one didn’t have any prefs, but Ansible was applying the prefs from the WFH role.

Eventually, I found that the problem lay in the two vars blocks in the wfh role’s dependencies: apparently those get set as variables for the entire task or play, not just for that invocation of the firefox role. The solution turned out to be undocumented: drop the vars blocks and pull the role parameters up a level:

dependencies:
  - name: Profile Work 1
    role: firefox
    profile: work1
    addons:
      - ublock-origin
      - privacy-badger17
      - solarize-fox
    prefs: >-
      network.proxy.http: '"proxy.host.com"'
      network.proxy.http_port: 1234
  - name: Profile Work 2
    role: firefox
    profile: work2
    addons:
      - ublock-origin
      - privacy-badger17
      - solarized-light
    prefs: >-
      network.proxy.http: '"proxy.host.com"'
      network.proxy.http_port: 1234

I do like Ansible, but it’s full of fiddly stupid crap like this.