# Display error message if variable isn't set using playbook **URL:** \ **Category:** Ansible Project\ **Created:** [May 5, 2014, 2:53pm UTC](https://forum.ansible.com/t/display-error-message-if-variable-isnt-set-using-playbook/15160 "2014-05-05T14:53:54Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Sam\_S](https://avatars.discourse-cdn.com/v4/letter/s/edb3f5/32.png) [@Sam\_S](https://forum.ansible.com/u/Sam_S)\ **Post date:** [May 5, 2014, 2:53pm UTC](https://forum.ansible.com/t/display-error-message-if-variable-isnt-set-using-playbook/15160/1 "2014-05-05T14:53:54Z")
Let’s say I ask for a revision\_no from the user. If the user doesn’t input a value, I would like to display a custom message. Right now ansible shows a bunch of “skipping” message, but I know my users would want to know why it skipped. - hosts: webservers user: deployment # serial: 1 vars\_prompt: - name: “revision\_no” prompt: “Input revision number” private: no vars\_files: - “group\_vars/deploy\_list” roles: - { role: web, when: revision\_no is not defined } ---
**Author:** ![Sam\_S](https://avatars.discourse-cdn.com/v4/letter/s/edb3f5/32.png) [@Sam\_S](https://forum.ansible.com/u/Sam_S)\ **Post date:** [May 5, 2014, 2:58pm UTC](https://forum.ansible.com/t/display-error-message-if-variable-isnt-set-using-playbook/15160/2 "2014-05-05T14:58:27Z")
That last line is supposed to read “revision\_no is defined” ---
**Author:** ![Garrett\_Plasky](https://avatars.discourse-cdn.com/v4/letter/g/5f9b8f/32.png) [@Garrett\_Plasky](https://forum.ansible.com/u/Garrett_Plasky)\ **Post date:** [May 5, 2014, 5:19pm UTC](https://forum.ansible.com/t/display-error-message-if-variable-isnt-set-using-playbook/15160/3 "2014-05-05T17:19:05Z")
There may be a better way to do this but I solved the problem by having a separate task initially that verifies the variable is set and fails the play if not (via the fail module). - name: Checking for required variables fail: msg=“Playbook execution failed - ‘revision\_no’ is required!” when: not revision\_no If you don’t want the play to outright fail, you could replace the fail module with something like debug. ---
**Author:** ![Michael\_DeHaan1](https://avatars.discourse-cdn.com/v4/letter/m/5e9695/32.png) [@Michael\_DeHaan1](https://forum.ansible.com/u/Michael_DeHaan1)\ **Post date:** [May 6, 2014, 3:51am UTC](https://forum.ansible.com/t/display-error-message-if-variable-isnt-set-using-playbook/15160/4 "2014-05-06T03:51:29Z")
You can say this specifically: when: revision\_no is not defined ---
**Author:** ![Sam\_S](https://avatars.discourse-cdn.com/v4/letter/s/edb3f5/32.png) [@Sam\_S](https://forum.ansible.com/u/Sam_S)\ **Post date:** [May 7, 2014, 8:34pm UTC](https://forum.ansible.com/t/display-error-message-if-variable-isnt-set-using-playbook/15160/5 "2014-05-07T20:34:31Z")
This does not work for me. Garrett’s example does … ---
**Author:** ![Sam\_S](https://avatars.discourse-cdn.com/v4/letter/s/edb3f5/32.png) [@Sam\_S](https://forum.ansible.com/u/Sam_S)\ **Post date:** [May 7, 2014, 9:02pm UTC](https://forum.ansible.com/t/display-error-message-if-variable-isnt-set-using-playbook/15160/6 "2014-05-07T21:02:59Z")
So, here’s the full site.yml file. If I dont input a revision number (I hit enter at the prompt), it throws the error message as expected BUT it also executes the role. I want it to bomb out w/ the error msg and not continue. ---
**Author:** ![Garrett\_Plasky](https://avatars.discourse-cdn.com/v4/letter/g/5f9b8f/32.png) [@Garrett\_Plasky](https://forum.ansible.com/u/Garrett_Plasky)\ **Post date:** [May 7, 2014, 9:21pm UTC](https://forum.ansible.com/t/display-error-message-if-variable-isnt-set-using-playbook/15160/7 "2014-05-07T21:21:58Z")
I believe this is because variables set via vars\_prompt are always defined. A workaround might be to set a default for revision\_no and check it doesn’t match in your role, e.g.: vars\_prompt: - name: “revision\_no" prompt: "Input revision number” default: “invalid” private: no …… roles: - { role: web, when: revision\_no != “invalid” } I’ve not made extensive use of roles so it seems odd to me that a role would still execute when a failure is thrown but it must have something to do with Ansible’s order of execution. ---
**Author:** ![Sam\_S](https://avatars.discourse-cdn.com/v4/letter/s/edb3f5/32.png) [@Sam\_S](https://forum.ansible.com/u/Sam_S)\ **Post date:** [May 7, 2014, 11:36pm UTC](https://forum.ansible.com/t/display-error-message-if-variable-isnt-set-using-playbook/15160/8 "2014-05-07T23:36:13Z")
I figured it out, not sure if this is valid. roles: - { role: web, when: revision\_no } ---
**Author:** ![Michael\_DeHaan1](https://avatars.discourse-cdn.com/v4/letter/m/5e9695/32.png) [@Michael\_DeHaan1](https://forum.ansible.com/u/Michael_DeHaan1)\ **Post date:** [May 9, 2014, 11:58pm UTC](https://forum.ansible.com/t/display-error-message-if-variable-isnt-set-using-playbook/15160/9 "2014-05-09T23:58:24Z")
Seems like your variable is defined then, just False. ---
**Author:** ![Stanislav\_Antic](https://avatars.discourse-cdn.com/v4/letter/s/e9c0ed/32.png) [@Stanislav\_Antic](https://forum.ansible.com/u/Stanislav_Antic)\ **Post date:** [May 10, 2014, 7:41am UTC](https://forum.ansible.com/t/display-error-message-if-variable-isnt-set-using-playbook/15160/10 "2014-05-10T07:41:45Z")
not revision\_no works because of you just do Enter it will have empty string and empty string is False. It’s matter of preference but I would test for that. You can always do debug to see true value: tasks: - debug: msg={{revision\_no}}