Ansible: Insert line if not exists

Question

I\'m trying insert a line in a property file using ansible. I want to add some property if it does not exist, but not replace it if such property already exists in the file.

Answer 1

We have tried the below and it worked well. our scenario need to entry "compress" in syslog file if it does not exist.

- name: Checking compress entry present if not add entry   
  lineinfile:
    path: /etc/logrotate.d/syslog
    regexp: "    compress"
    state: present
    insertafter: "    missingok"
    line: "    compress"