How to ignore specific errors in an Ansible task - ansible

Question

If have an Ansible task, that can fails sometimes, due to some error during the creation of an user account. Especially if the user account is already in use and the user is logged in. If the task fails with a specific error message, like "user account in use" the play must continue. There is no need to fail then, but only on predefined error messages. The task looks like this.
- name: modify user
user:
state: "{{ user.state | default('present') }}"
name: "{{ user.name }}"
home: "{{ user_base_path }}/{{ user.name }}"
createhome: true
Since it's not a shell command, I cannot simply register a var and check the output of .rc. Also I don't get stderr or stdout, when i register a var and print it in debug mode. That was my first approach on check for the error message. I am running out of ideas, how to filter for a specific error and passing the task, but failing on everything else. ignore_errors: yes is not a good solution, because the task should fail in some cases.

Answer 1

As per ansible doc we get stdout and stderr as return fields.
I would suggest to use flag ignore_errors: yes and catch the return as per this example
---
- hosts: localhost
vars:
user:
name: yash
user_base_path: /tmp
tasks:
- name: modify user
user:
state: "{{ user.state | default('present') }}"
name: "{{ user.name }}"
home: "{{ user_base_path }}/{{ user.name }}"
createhome: true
register: user_status
ignore_errors: yes
- name: stdout_test
debug:
msg: "{{ user_status.err }}"
- name: Fail on not valid
fail:
msg: failed
when: '"user account in use" not in user_status.err'
Output:
PLAY [localhost] *************************************************************************************************************************************************************************************
TASK [Gathering Facts] *******************************************************************************************************************************************************************************
ok: [localhost]
TASK [modify user] ***********************************************************************************************************************************************************************************
fatal: [localhost]: FAILED! => {"changed": false, "err": "<main> attribute status: eDSPermissionError\n<dscl_cmd> DS Error: -14120 (eDSPermissionError)\n", "msg": "Cannot create user \"yash\".", "out": "", "rc": 40}
...ignoring
TASK [stdout_test] ***********************************************************************************************************************************************************************************
ok: [localhost] => {
"msg": "<main> attribute status: eDSPermissionError\n<dscl_cmd> DS Error: -14120 (eDSPermissionError)\n"
}
TASK [Fail on not valid] *****************************************************************************************************************************************************************************
fatal: [localhost]: FAILED! => {"changed": false, "msg": "failed"}
PLAY RECAP *******************************************************************************************************************************************************************************************
localhost : ok=3 changed=0 unreachable=0 failed=1 skipped=0 rescued=0 ignored=1

Answer 2

You can use when, save the return value by the register and set_fact and then bet what will happen according to that value.