---
# TASK DESCRIPTION:
# Downloads, installs, and configures Prometheus Node Exporter.
#
# NOTE: This is depreciated, I no longer use Prometheus and have migrated to Telegraf

- name: Populate service facts
  ansible.builtin.service_facts:

- name: Stop node_exporter
  become: true
  ansible.builtin.systemd:
      name: node_exporter
      state: stopped
  when: ansible_facts.services["node_exporter.service"] is defined

- name: Ensure group "prometheus" exists
  become: true
  ansible.builtin.group:
      name: prometheus
      state: present

- name: Add the user 'prometheus' with group 'prometheus'
  become: true
  ansible.builtin.user:
      name: prometheus
      group: prometheus
      groups: docker
      append: true

# --------------- Install or Update Prometheus
- name: "Set fact: need to install Prometheus?"
  ansible.builtin.set_fact:
      need_prometheus_install: false

- name: Check if node_exporter is installed
  ansible.builtin.stat:
      path: /usr/local/bin/node_exporter
  register: prometheus_binary_file_location

- name: "Set fact: need to install Prometheus?"
  ansible.builtin.set_fact:
      need_prometheus_install: true
  when:
      - not prometheus_binary_file_location.stat.exists

- name: Check current version of Prometheus
  ansible.builtin.shell: /usr/local/bin/node_exporter --version 3>&1 1>&2 2>&3 | head -n1 | grep -oE '[0-9]+\.[0-9]+\.[0-9]+'
  ignore_errors: true
  register: current_prometheus_version
  failed_when: false
  changed_when: false
  check_mode: false
  when:
      - need_prometheus_install is false

- name: "Set fact: need to install Prometheus?"
  ansible.builtin.set_fact:
      need_prometheus_install: true
  when:
      - need_prometheus_install is false
      - current_prometheus_version.stdout != prometheus_verssion

- name: Install node_exporter
  become: true
  ansible.builtin.unarchive:
      src: "https://github.com/prometheus/node_exporter/releases/download/v{{ prometheus_verssion }}/node_exporter-{{ prometheus_verssion }}.linux-armv7.tar.gz"
      dest: /usr/local/bin
      group: prometheus
      owner: prometheus
      # reference for extra_opts: https://github.com/ansible/ansible/issues/27081
      extra_opts:
          - --strip=1
          - --no-anchored
          - "node_exporter"
      remote_src: true
  when:
      - need_prometheus_install is true

- name: Create node_exporter service
  become: true
  ansible.builtin.template:
      src: node_exporter.service.j2
      dest: /etc/systemd/system/node_exporter.service
      mode: 0644

- name: Start node_exporter
  become: true
  ansible.builtin.systemd:
      name: node_exporter
      daemon_reload: true
      enabled: true
      state: started
  when:
      - "'nostart' not in ansible_run_tags"