#
# Cookbook:: kosmos_prometheus
# Recipe:: node_exporter
#

include_recipe "firewall"

version = node["kosmos_prometheus"]["node_exporter"]["version"]
checksum = node["kosmos_prometheus"]["node_exporter"]["checksum"]
tarball = "#{Chef::Config[:file_cache_path]}/node_exporter-#{version}.linux-amd64.tar.gz"
binary_url = "https://github.com/prometheus/node_exporter/releases/download/v#{version}/node_exporter-#{version}.linux-amd64.tar.gz"

group "node_exporter"

user "node_exporter" do
  gid "node_exporter"
  system true
  shell "/bin/false"
  home "/nonexistent"
end

directory "/var/lib/node_exporter/textfile" do
  owner "node_exporter"
  group "node_exporter"
  mode "0755"
  recursive true
end

package %w(tar bzip2)

remote_file tarball do
  source binary_url
  checksum checksum
  action :create
  notifies :run, "execute[install_node_exporter]", :immediately
end

execute "install_node_exporter" do
  command "tar -xzf #{tarball} -C /usr/local/bin --strip-components=1 node_exporter-#{version}.linux-amd64/node_exporter"
  action :nothing
  notifies :restart, "service[node_exporter]", :delayed
end

file "/usr/local/bin/node_exporter" do
  owner "root"
  group "root"
  mode "0755"
  notifies :restart, "service[node_exporter]", :delayed
end

systemd_unit "node_exporter.service" do
  content({
    Unit: {
      Description: "Prometheus node exporter",
      Documentation: ["https://github.com/prometheus/node_exporter"],
    },
    Service: {
      Type: "simple",
      User: "node_exporter",
      Group: "node_exporter",
      ExecStart: "/usr/local/bin/node_exporter --web.listen-address=:9100 --collector.textfile.directory=/var/lib/node_exporter/textfile",
      Restart: "on-failure",
      RestartSec: "5",
      NoNewPrivileges: "yes",
      ProtectSystem: "full",
      ProtectHome: "yes",
    },
    Install: {
      WantedBy: "multi-user.target",
    },
  })
  triggers_reload true
  action :create
end

service "node_exporter" do
  action [:enable, :start]
end

firewall_rule "node_exporter" do
  port 9100
  source "10.1.1.0/24"
  protocol :tcp
  command :allow
end