CODEWITHSUNDEEP
ansible
EM0
EM0

Reputation: 6337

Check that only one of several Ansible variables is defined

I want to check that only one of several Ansible variables is defined. It seems that Ansible conditions don't support xor. The best way I've found so far is something like this:

  - fail:
      msg: "var1 xor var2 xor var3 must be defined"
    when: (var1 is defined | ternary(1, 0) + var2 is defined | ternary(1, 0) + var3 is defined | ternary(1, 0)) != 1

Dictionary version:

(item.get('key1') | ternary(1, 0) + item.get('key2') | ternary(1, 0) + thedict.get('key3') | ternary(1, 0)) != 1

Is there a simpler way?

Upvotes: 0

Views: 1420

Answers (2)

techraf
techraf

Reputation: 68559

This should count as simpler:

- fail:
    msg: "only one of var1, var2, or var3 must be defined"
  when: checklist | select() | list | length != 1
  vars:
    checklist:
      - "{{ var1 is defined }}"
      - "{{ var2 is defined }}"
      - "{{ var3 is defined }}"

Upvotes: 3

Vladimir Botka
Vladimir Botka

Reputation: 68134

As of Ansible 2.6 there isn't simpler way IMHO. To test list of conditions (see Group theory tests) there is only AND (list is all) and OR (list is any).

Upvotes: 0

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