How to make Ansible execute a shell script if a package is not installed

Question

How can I make Ansible execute a shell script if a (rpm) package is not installed? Is it somehow possible to leverage the yum module?

Answer 1

I find using shell or command module is not "ansiblic".

I prefer to use yum module and json_query filter to check if a package is already installed. E.g. httpd package :

    - yum:
        list: httpd
      register: apache_service

    - assert:
        that:
          - "'installed' in apache_service|json_query('results[*].yumstate')"
      msg: 'httpd is not installed'