# select a cluster node that can host a role

- name: ensure there is at least one cluster node
  fail:
    msg: no cluster nodes are defined
  when: (groups['nodes'] | d([]) | length) == 0


- name: clear selected_node
  set_fact:
    selected_node: ""


- name: preference-based node determination
  block:
    - name: determine first cluster node which prefers to host role
      set_fact:
        selected_node: "{{ item }}"
      when:
        - hostvars[item] is defined
        - hostvars[item].can_host is defined
        - hostvars[item].can_host is iterable
        - hostvars[item].can_host is not mapping
        - hostvars[item].can_host is not string
        - hostvars[item].can_host[primary_role | d(inventory_hostname)] is defined
        - (hostvars[item].never_host is not defined) or
          (hostvars[item].never_host[primary_role | d(inventory_hostname)] is not defined)
        - not selected_node
      loop: "{{ groups['nodes'] }}"

  when: (hosted_on is not defined) and (inventory_hostname is defined)


- name: pin-based node determination
  block:
    - name: fail if pinned node is not a string
      fail:
        msg: 'pinned node for "{{ inventory_hostname }}" must be a string'
      when: hosted_on is not string

    - name: fail if pinned node does not exist
      fail:
        msg: '"{{ inventory_hostname }}" has a nonexistent pinned node "{{ hosted_on }}"'
      when: hostvars[hosted_on] is not defined

    - name: select pinned cluster node
      set_fact:
        selected_node: "{{ hosted_on }}"

  when: (hosted_on is defined) and (inventory_hostname is defined)


- name: fallback to first cluster node
  set_fact:
    selected_node: "{{ groups['nodes'][0] }}"
  when: not selected_node


- name: determine actual node in a cluster configuration
  block:
    - set_fact:
        is_node_found: no

    - name: determine on which node this container is currently hosted on
      include_tasks: tasks/query_node.yml
      loop: "{{ groups['nodes'] }}"
      loop_control:
        loop_var: node

  when: groups['nodes'] | length >= 2
  rescue:
    - name: report that cluster cannot be queried
      debug:
        msg: 'cluster cannot be queried or all nodes are inaccessible, will keep cluster mode: "{{ selected_node }}"'


- name: report which node was selected
  debug:
    msg: 'using cluster node: "{{ selected_node }}"'


- name: ensure this node exists and can be connected to
  wait_for_connection:
    timeout: 10
  delegate_to: "{{ selected_node }}"