Set command output as facts with ansible

Having to check ntp configuration on a distributed cluster, I had to parse the “`timedatectl“` output into a dict and apply various checks.

I did this via the (infamous) 😉 jinja templates|pipelines.

# This is the check_time.yml playbook.

- name: Register the timedatectl output even in check mode. This command doesn't modify server configuration.
  shell: "timedatectl | grep ': '"
  check_mode: no
  register: timedatectl_output

# Note that:
#  - to use timedatectl_output into with_items we need to QUOTE-AND-BRACE it
#  - we can default the previously indefined timedatectl_status dictionary via
#       variable | default(VALUE)
#  - 
- name: Process timedatectl_output lines one at a time and update repeatedly the timedatectl_status variable using combine().
  set_fact:
    timedatectl_status: >
      {{
        timedatectl_status | default({}) |
        combine(
          dict([ item.partition(': ')[::2]|map('trim') ])
        )
      }}
  with_items: "{{timedatectl_output.stdout_lines}}"

Now we can check 😉


- name: Clock synchronized
  fail: msg="Clock unsynchronized {{timedatectl_status}}"
  when: "{{timedatectl_status['NTP synchronized'] == 'no' }}"

- name: All hw clocks are utc
  fail: msg="hwclock not utc {{timedatectl_status}}"
  when: "{{timedatectl_status['RTC in local TZ'] == 'no' }}"