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Ryan
Asked: 2013-08-12 02:33:58 +0800 CST

Force Ansible to throw out error when vars is missing in yml?

  • 772

Is it possible to force Ansible when replacing the var in yml files, which is undefined, throw out an error instead silently replaced by an empty string?

ansible

4 Answers

  1. Yes, it is possible. Check the online documentation, under accessing complex variable data.

    An example is provided to do exactly that:

    tasks:
    - shell: echo "I've got '{{ foo }}' and am not afraid to use it!"
      when: foo is defined

    - fail: msg="Bailing out: this play requires 'bar'"
      when: bar is not defined
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  2. Add this line to the [defaults] section of your ansible.cfg:

    error_on_undefined_vars = True

    You'll now get an error message if a variable is undefined.

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  3. Define your variables in 

    roles/<role_name>/defaults/main.yml

    like:

    SUPERVAR:
  VAR1:foo
  VAR2:bar

    and then do in 

    roles/<role_name>/tasks/main.yml

    like:

    - fail: msg="{{ item }} is not defined"
  when: not {{ item }}
  with_items:
    - SUPERVAR.VAR1
    - SUPERVAR.VAR2
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  4. You can use mandatory-values

    If you configure Ansible to ignore undefined variables, you may want to define some values as mandatory. By default, Ansible fails if a variable in your playbook or command is undefined. You can configure Ansible to allow undefined variables by setting DEFAULT_UNDEFINED_VAR_BEHAVIOR to false. In that case, you may want to require some variables to be defined. You can do this with:

    {{ variable | mandatory }}

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