Ansible - Using Variables in When Condition

[Netmart]

Hello,

I was wondering, if it is possible to use variable in a search string within a WHEN block:

- name: Ansible site-ios-xe-L2-L3-Metrics-Check

  hosts: IDFiosxe

  vars_files:

         - /home/cisco/Ansible/vault_password.yml

  vars:

      ansible_become_pass: "{{ vault_sudo_password }}"

      ansible_python_interpreter: /usr/bin/python3

      image:

         - cat4500es8-universalk9.SPA.03.11.10.E.152-7.E10.bin

         - cat4500es8-universalk9.SPA.03.11.9.E.152-7.E10.bin

         - cat4500es8-universalk9.SPA.03.11.8.E.152-7.E10.bin

:

     - name: Task34.4 - result - bootvar-Match

       debug:

       #var: output

          msg: " OK: Boot Variance is updated with latest new image {{image[0]}} @ {{inventory_hostname}} "

       when:

         - output34.stdout is search("BOOT variable = bootflash:{{image[0]}},1;")

         - output34.stdout is search("Standby BOOT variable = bootflash:{{image[0]}}n,1;")

Do this Ansible is complaining:

variable = bootflash:{{image[0]}},1;")
[WARNING]: conditional statements should not include jinja2 templating
delimiters such as {{ }} or {% %}. Found: output34.stdout is search("Standby

Therefore, I am wondering whether there is any alternative to achieve the same.

Thanks,

Martin

[Torbjørn · Accepted solution]

When trying to solve this it is useful to understand why it doesn't allow the use of Jinja delimiters. To quote the Ansible docs: "The when clause is a raw Jinja2 expression without double curly braces". You should hence write a regular jinja expression, within which it is not natural to use Jinja delimiters. You should be able to use these expressions using the concatenation operator(~):

output34.stdout is search("BOOT variable = bootflash: " ~ image[0])
output34.stdout is search("Standby BOOT variable = bootflash: " ~ image[0])

You can read more about Ansible conditionals and Jinja2 expressions here:

https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_conditionals.html

https://jinja.palletsprojects.com/en/3.1.x/templates/#expressions

[Netmart]

Thank you Torbjoern.

Yes it worked by using the  concatenation operator(~) as suggested by you.

Is there another way to do or would recommend keep using the concatenation operator(~).

Thanks..

[Torbjørn]

No problem!

I think this is a good way to solve the task at hand. Its simple, robust and unlikely to result in false positives. I would leave it as it is.