check_syslog-ng.yml

---
- name: check for syslog-ng
  hosts: "{{ target_host }}"
  become: true

  # check for the apt package
  tasks:
  - name: check and install syslog-ng apt package
    apt:
      name: 
        - syslog-ng
    become: true

  # check if the config file is there (if just installed syslog-ng, it shouldn't be)
  - name: check if config file exists
    stat:
      path: "/etc/syslog-ng/conf.d/loki.conf"
    become: true
    register: lokifile

  # debug print to see if file exists during execution
  - name: Print if Loki Conf File Exists
    debug:
      var: lokifile.stat.exists

  # if file does not exist (previous check) go ahead and create it
  - name: create config file
    file:
      path: /etc/syslog-ng/conf.d/loki.conf
      state: touch
    register: lokifile_created
    when: not lokifile.stat.exists

  # debug print to see if file was created during execution (only if it didn't exist)
  - name: print lokifile_created
    debug:
      var: lokifile_created.changed
    #when: not lokifile.stat.exists

  # if file exists or was created check for destination
  - name: check destination for loki
    lineinfile:
      path: /etc/syslog-ng/conf.d/loki.conf
      regexp: '^destination d_loki'
      line: 'destination d_loki {syslog("{{ loki_server }}" transport("tcp") port(1514)); };'
    become: true
    register: destchanged
    when: (lokifile.stat.exists or lokifile_created.changed)

  # debug print to see if destination changed
  - name: print destchanged
    debug:
      var: destchanged.changed
    when: (lokifile.stat.exists or lokifile_created.changed)

  # if file exists or was created check for source route
  - name: check log route from source to destination
    lineinfile:
      path: /etc/syslog-ng/conf.d/loki.conf
      regexp: '^log { source(s_src)'
      line: 'log { source(s_src); destination(d_loki); };'
    become: true
    register: sourceroute
    when: (lokifile.stat.exists or lokifile_created.changed)

  # debug print to see if source route changed
  - name: print sourceroute
    debug:
      var: sourceroute.changed
    when: (lokifile.stat.exists or lokifile_created.changed)

  # restart if anything was changed, no need to check if the file is there.
  - name: Restart syslog-ng service
    service:
      name: syslog-ng
      state: restarted
    become: true
    when: (destchanged.changed or sourceroute.changed)