---
- name: Install Prometheus Node Exporter
  hosts: all
  become: yes

  tasks:
    - name: Install dependencies
      apt:
        name:
          - libffi-dev
          - python3
          - python3-pip
          - python3-setuptools
        state: latest
        update_cache: true

    - name: Upgrade pip
      pip:
        name: pip
        state: latest

    - name: Install required pip packages
      pip:
        name:
          - pyopenssl
        state: present

    - name: Create node_exporter group
      group:
        name: "node_exporter"
        state: present
        system: true

    - name: Create node_exporter user
      user:
        name: "node_exporter"
        group: "node_exporter"
        comment: "Node Exporter"
        shell: /bin/false
        home: "/usr/sbin/nologin"
        system: true
        state: present

    - name: Create config directory
      file:
        path: "/etc/node_exporter"
        state: directory
        owner: "node_exporter"
        group: "node_exporter"

    - name: Generate an OpenSSL private key
      openssl_privatekey:
        path: /etc/node_exporter/node_exporter.key
        owner: "node_exporter"
        group: "node_exporter"

    - name: Generate an OpenSSL Certificate Signing Request
      openssl_csr:
        path: /etc/node_exporter/node_exporter.csr
        privatekey_path: /etc/node_exporter/node_exporter.key
        common_name: localhost
        owner: "node_exporter"
        group: "node_exporter"

    - name: Generate a Self Signed OpenSSL certificate
      openssl_certificate:
        path: /etc/node_exporter/node_exporter.crt
        privatekey_path: /etc/node_exporter/node_exporter.key
        csr_path: /etc/node_exporter/node_exporter.csr
        provider: selfsigned
        owner: "node_exporter"
        group: "node_exporter"        

    - name: Copy config
      template:
        src: config.yml.j2
        dest: /etc/node_exporter/config.yml
        owner: "node_exporter"
        group: "node_exporter"
        mode: 0755        

    - name: Download and unzip Node Exporter
      unarchive:
        src: "https://github.com/prometheus/node_exporter/releases/download/v{{ node_exporter_version }}/node_exporter-{{ node_exporter_version }}.linux-amd64.tar.gz"
        dest: /tmp/
        remote_src: yes
        validate_certs: no

    - name: Move the binary to the installation directory
      copy:
        src: "/tmp/node_exporter-{{ node_exporter_version }}.linux-amd64/node_exporter"
        dest: "/usr/local/bin/node_exporter"
        owner: "node_exporter"
        group: "node_exporter"
        mode: 0755
        remote_src: true

    - name: Remove archive
      file:
        path: /tmp/node_exporter-{{ node_exporter_version }}.linux-amd64/
        state: absent

    - name: Install service
      template:
        src: node_exporter.service.j2
        dest: /etc/systemd/system/node_exporter.service
        owner: root
        group: root
        mode: 0755

    - name: Restart service and pickup changes
      systemd:
        state: restarted
        daemon_reload: yes
        name: node_exporter.service
        enabled: yes