Nesting roles and omitting vars

[Arnaud Mazin]

Hi

I'm trying to nest roles using dependencies in order to reuse as much code as possible and get into trouble when trying to omit some parameters

My setup:

# roles/roleA/tasks/main.yml
---
- debug: msg="var var_rolea is set to {{ var_rolea|default('no idea') }}"

# roles/roleB/meta/main.yml
dependencies:
  - { role: roleA,
      var_rolea: "{{ var_roleb }}"
    }

# playbook
# play1, specify value
- hosts: localhost
  gather_facts: no
  roles:
    - role: roleB
      var_roleb: plop

# play2, omit value, let defaults apply
- hosts: localhost
  gather_facts: no
  roles:
    - role: roleB

I get a « fatal: [localhost] => One or more undefined variables: 'var_roleb' is undefined » error in this case.

I tried several tricks into the roleB/meta/main.yml, such as:

• var_rolea: "{{ var_roleb|default(omit) }}"
  
• var_rolea: "{{ var_roleb|default(None) }}"
  

But so far, I haven't found a pretty way to do this.

Any Idea?

Regards,

Arnaud

[Trond Hindenes]

In your RoleB role, use a defaults file to handle default variables. That will ensure you always have the var_roleb variable defined.

http://docs.ansible.com/ansible/playbooks_roles.html#role-default-variables

[Arnaud Mazin]

Hello.

It doesn't exactly meet my need, I'd like to be able to write:

# roles/roleA/tasks/main.yml
---
- file: path=/tmp/foo owner="{{ var_rolea|default(omit) }}"