Ansible print SSLcertificate expire days - ansible

Question

I have this play to print certificate expire days. but its giving the AnsibleUndefined error. How to fix this error message.
Running this on Ansible 2.8 with Python 3.
Tasks
- name: Get a cert from an https port
get_certificate:
host: "{{ inventory_hostname }}"
port: 10250
delegate_to: "{{ inventory_hostname }}"
run_once: true
register: cert
- name: Cert output
debug:
msg: "{{ cert }}"
- name: How many days until cert expires
debug:
msg: "cert expires in: {{ expire_days }} days."
vars:
expire_days: "{{ (( cert.not_after | to_datetime('%Y%m%d%H%M%SZ')) - (ansible_date_time.iso8601 | to_datetime('%Y-%m-%dT%H:%M:%SZ')) ).days }}"
output and error message.
"failed": false,
"issuer": {
"CN": "kubernetes"
},
"not_after": "20290827151600Z",
"not_before": "20190830151600Z",
"serial_number": 552511748902341611097595302509251707409941832746,
"signature_algorithm": "sha256WithRSAEncryption",
version": 2
}
}
TASK [test : How many days until cert expires] ***********************************************************************************************************************************************
fatal: []: FAILED! => {"msg": "The task includes an option with an undefined variable. The error was: Unable to look up a name or access an attribute in template string ({{ (( cert.
not_after | to_datetime('%Y%m%d%H%M%SZ')) - (ansible_date_time.iso8601 | to_datetime('%Y-%m-%dT%H:%M:%SZ')) ).days }}).\nMake sure your variable name does not contain invalid characters like
'-': strptime() argument 1 must be str, not AnsibleUndefined\n\nThe error appears to be in '/playbooks/roles/test/tasks/main.yaml': line 23, column 3, but may\nbe elsewhere in the file depe
nding on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n- name: How many days until cert expires\n ^ here\n"}

Answer 1

I was running gather_facts: no setting. When I change it to gather_facts: yes. Now its working as expected.