# Ansible handler with when condition **URL:** \ **Category:** Get Help\ **Created:** [November 14, 2023, 2:56pm UTC](https://forum.ansible.com/t/ansible-handler-with-when-condition/2366 "2023-11-14T14:56:01Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![erichymowitz](https://avatars.discourse-cdn.com/v4/letter/e/9d8465/32.png) [@erichymowitz](https://forum.ansible.com/u/erichymowitz)\ **Post date:** [November 14, 2023, 2:56pm UTC](https://forum.ansible.com/t/ansible-handler-with-when-condition/2366/1 "2023-11-14T14:56:01Z")
So I have this playbook ```auto - hosts: localhost gather_facts: no vars: this_thing_is_true: true use_handler: false tasks: - debug: msg: 'Notifying handlers' changed_when: this_thing_is_true notify: - me handlers: - name: me debug: msg: 'I have been notified' when: use_handler is true ``` And when I run it, as expected, the handler doesn’t run. ```auto # ansible-playbook handler.yml PLAY [localhost] *************************************************************** TASK [debug] ******************************************************************* changed: [localhost] => { "msg": "Notifying handlers" } RUNNING HANDLER [me] *********************************************************** skipping: [localhost] ``` I can activate the handler by changing the `use_handler` variable in the playbook. ```auto # ansible-playbook handler.yml PLAY [localhost] *************************************************************** TASK [debug] ******************************************************************* changed: [localhost] => { "msg": "Notifying handlers" } RUNNING HANDLER [me] *********************************************************** ok: [localhost] => { "msg": "I have been notified" } ``` However, I thought this would also activate the handler … but it doesn’t. ```auto # ansible-playbook -e use_handler=true handler.yml PLAY [localhost] *************************************************************** TASK [debug] ******************************************************************* changed: [localhost] => { "msg": "Notifying handlers" } RUNNING HANDLER [me] *********************************************************** skipping: [localhost] ``` Am I doing something wrong? ---
**Author:** ![utoddl](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/utoddl/32/249_2.png) [@utoddl](https://forum.ansible.com/u/utoddl)\ **Post date:** [November 14, 2023, 3:31pm UTC](https://forum.ansible.com/t/ansible-handler-with-when-condition/2366/2 "2023-11-14T15:31:15Z")
The problem is that it’s impractical to pass a bool into a run with `key=value` style extra variables on the command line. To set a bool, you’ll need to use JSON. Behold: ```txt [utoddl@tango ansible]$ ansible localhost -e use_handler=true -m debug -a '{"msg": "{{ use_handler | type_debug }}"}' localhost | SUCCESS => { "msg": "str" } [utoddl@tango ansible]$ ansible localhost -e '{"use_handler": true}' -m debug -a '{"msg": "{{ use_handler | type_debug }}"}' localhost | SUCCESS => { "msg": "bool" } ``` See [this](https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_variables.html#key-value-format): > Use the JSON format if you need to pass non-string values such as Booleans, integers, floats, lists, and so on. ---
**Author:** ![erichymowitz](https://avatars.discourse-cdn.com/v4/letter/e/9d8465/32.png) [@erichymowitz](https://forum.ansible.com/u/erichymowitz)\ **Post date:** [November 14, 2023, 6:59pm UTC](https://forum.ansible.com/t/ansible-handler-with-when-condition/2366/3 "2023-11-14T18:59:34Z")
Thank you very much. I will also note that this construct also worked, since it uses a string and not a boolean ``` when: use_handler == 'true' ``` ---
**Author:** ![utoddl](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/utoddl/32/249_2.png) [@utoddl](https://forum.ansible.com/u/utoddl)\ **Post date:** [November 14, 2023, 7:27pm UTC](https://forum.ansible.com/t/ansible-handler-with-when-condition/2366/4 "2023-11-14T19:27:53Z")
While that does work, if you plan to use strings, I’d recommend you make them look like strings rather than Booleans. We spent _days_ one time disentangling a rat’s nest of strings, bools, and strings-as-bools. The amazing thing is that it worked as long as we didn’t fix any single obvious error! Anyway, consider something like ```auto when: handler_state | default('disabled') == 'enabled' ``` It’s easy to get right on the command line in either `key=value` or JSON form, and doesn’t tax your brain to read later. Cheers. ---
**Author:** ![laurent-indermuehle](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/laurent-indermuehle/32/289_2.png) [@laurent-indermuehle](https://forum.ansible.com/u/laurent-indermuehle)\ **Post date:** [November 14, 2023, 8:00pm UTC](https://forum.ansible.com/t/ansible-handler-with-when-condition/2366/5 "2023-11-14T20:00:55Z")
I want to add (because I learned that the hard way) that you should always transform your “bool” variable with the bool filter in the playbook. If one day you decide to use AWX/AAP, your variable will always be a string even if you thought you send a bool. So the correct way to write your line: ```yml when: use_handler is true ``` is: ```yml when: use_handler | bool is true ``` Or even better (and supported since Ansible 2.10): ```yml when: use_handler is truthy(convert_bool=True) ``` From the documentation: [Tests — Ansible Documentation](https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_tests.html#testing-truthiness) ---
**Author:** ![chris](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/chris/32/293_2.png) [@chris](https://forum.ansible.com/u/chris)\ **Post date:** [November 14, 2023, 9:44pm UTC](https://forum.ansible.com/t/ansible-handler-with-when-condition/2366/6 "2023-11-14T21:44:32Z")
> [@laurent-indermuehle](#): > > ```yaml > when: use_handler | bool is true > > ``` Is that practically any different from: ```yaml when: use_handler | bool ``` I’ve been using this form, I’ll add `is true` if that might make a difference in some circumstances? ---
**Author:** ![utoddl](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/utoddl/32/249_2.png) [@utoddl](https://forum.ansible.com/u/utoddl)\ **Post date:** [November 15, 2023, 6:58am UTC](https://forum.ansible.com/t/ansible-handler-with-when-condition/2366/7 "2023-11-15T06:58:15Z")
They are not functionally different. `ansible-lint` will berate you mercilessly for the redundant `is true` bit. If you stick with `bool`s rather than strings, use [Laurent’s suggestion](http://forum.ansible.com/t/ansible-handler-with-when-condition/2366/5) and use the `truthy` test. (In fact, consider marking that post as the solution. It makes the admins happy, and @laurent-indermuehle could use the quatloos.) ---
**Author:** ![laurent-indermuehle](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/laurent-indermuehle/32/289_2.png) [@laurent-indermuehle](https://forum.ansible.com/u/laurent-indermuehle)\ **Post date:** [November 15, 2023, 8:18am UTC](https://forum.ansible.com/t/ansible-handler-with-when-condition/2366/8 "2023-11-15T08:18:15Z")
> [@chris](#): > > Is that practically any different As one Python poem taught me: Explicit is better than implicit. ---
**Author:** ![system](https://us1.discourse-cdn.com/ansible/original/1X/1882d9a01da5d8996a862359b0913cc568a39b84.svg) [@system](https://forum.ansible.com/u/system)\ **Post date:** [July 10, 2024, 12:17pm UTC](https://forum.ansible.com/t/ansible-handler-with-when-condition/2366/9 "2024-07-10T12:17:34Z")
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