#
# Cookbook:: kosmos_prometheus
# Recipe:: server
#

include_recipe "firewall"

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

group "prometheus"

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

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

directory "/etc/prometheus" do
  owner "root"
  group "root"
  mode "0755"
  recursive true
end

directory "/etc/prometheus/rules" do
  owner "root"
  group "root"
  mode "0755"
  recursive true
end

package %w(tar bzip2)

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

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

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

template "/etc/prometheus/prometheus.yml" do
  source "prometheus.yml.erb"
  owner "root"
  group "prometheus"
  mode "0644"
  variables(
    global_config: node["kosmos_prometheus"]["global"],
    jobs: node["kosmos_prometheus"]["jobs"],
    rule_files: node["kosmos_prometheus"]["rule_files"]
  )
  notifies :reload, "service[prometheus]", :delayed
end

systemd_unit "prometheus.service" do
  content({
    Unit: {
      Description: "Prometheus",
      After: "network.target",
    },
    Service: {
      Type: "simple",
      User: "prometheus",
      Group: "prometheus",
      ExecStart: "/usr/local/bin/prometheus --config.file=/etc/prometheus/prometheus.yml --storage.tsdb.path=/var/lib/prometheus --storage.tsdb.retention.time=15d --web.listen-address=:9090 --web.enable-lifecycle",
      ExecReload: "/bin/kill -HUP $MAINPID",
      Restart: "on-failure",
      RestartSec: "5",
    },
    Install: {
      WantedBy: "multi-user.target",
    },
  })
  triggers_reload true
  action :create
end

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

firewall_rule "prometheus web" do
  port 9090
  source "10.1.1.0/24"
  protocol :tcp
  command :allow
end