playbooks/generate_secrets.yml

---
- hosts: localhost
  gather_facts: false
  tasks:
    - name: Ensure the secrets file exists
      ansible.builtin.file:
        path: "{{ secrets_path }}"
        state: touch

    - name: Load the current secrets into a variable
      ansible.builtin.include_vars:
        file: "{{ secrets_path }}"
        name: secrets

    - name: Generate secrets for missing variables
      ansible.builtin.set_fact:
        secrets: "{{ secrets| default({}) | combine({item: lookup('password', '/dev/null chars=ascii_lowercase,ascii_uppercase,digits length=32')}) }}"
      # NOTE(mnaser): We don't want to override existing secrets, so we generate
      #               a new one if and only if it doesn't exist
      when: item not in secrets
      # NOTE(mnaser): This is absolutely hideous but there's no clean way of
      #               doing this using `with_fileglob` or `with_filetree`
      with_lines: >
        ls {{ playbook_dir }}/../roles/*/defaults/main.yml |
          xargs grep undef |
            egrep -v '(_host|region_name)' |
              cut -d':' -f2

    - name: Write new secrets file to disk
      ansible.builtin.copy:
        content: "{{ secrets | to_nice_yaml }}"
        dest: "{{ secrets_path }}"