I am trying to write an Ansible playbook that only compiles Nginx if it\'s not already present and at the current version. However it compiles every time which is undesirable.>
Since var is a json string you can parse it to json and access it's keys.
set_fact:
var_json: "{{ var.stdout|from_json }}"
Then access the json and get the value you want.
when: var_json.nginxVersion.stdout == 'nginx version: nginx/1.8.0'
checkout this link: https://gist.github.com/justinhennessy/28e82c2ec05f9081786a