NGINX Amplify installation changes `agent.conf` even if it's already in the desired state

[alvise1988]

Is your feature request related to a problem? Please describe

When installing NGINX Amplify via this role, /etc/amplify-agent/agent.conf is always replaced by /etc/amplify-agent/agent.conf.default, regardless of whether this is necessary or not, which makes the role always return changed ansible tasks, even if no change should happen.

Describe the solution you'd like

When the target server is in the desired state, ansible should return changed=0.

Describe alternatives you've considered

I am definitely not an ansible expert and I am sure there are better ways to address this issue, but what I would personally do is split the task:

- name: Copy NGINX Amplify configurator agent configuration template
  ansible.builtin.copy:
    remote_src: true
    src: /etc/amplify-agent/agent.conf.default
    dest: /etc/amplify-agent/agent.conf
    mode: "0644"

into:

- name: Check if NGINX Amplify config file template has changed
  ansible.builtin.copy:
    remote_src: true
    src: /etc/amplify-agent/agent.conf.default
    dest: /etc/amplify-agent/agent.conf.current
    mode: "0644"
    register: nginx_amplify_config_template

- name: Replace NGINX Amplify config file only if the template changed
  ansible.builtin.copy:
    remote_src: true
    src: /etc/amplify-agent/agent.conf.current
    dest: /etc/amplify-agent/agent.conf
    mode: "0644"
    when: nginx_amplify_config_template.changed

Additional context

The behaviour above is even more problematic when the agent configuration file is further edited by subsequent tasks, for example when monitoring MySQL. In fact, all customisations to agent.conf must be reapplied with each ansible run.