#
# Cookbook:: kosmos_prometheus
# Recipe:: alertmanager
#

include_recipe "firewall"

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

group "alertmanager"

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

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

directory "/etc/prometheus" 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_alertmanager]", :immediately
end

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

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

template "/etc/prometheus/alertmanager.yml" do
  source "alertmanager.yml.erb"
  owner "root"
  group "alertmanager"
  mode "0644"
  notifies :restart, "service[alertmanager]", :delayed
end

systemd_unit "alertmanager.service" do
  content({
    Unit: {
      Description: "Prometheus Alertmanager",
      After: "network.target",
    },
    Service: {
      Type: "simple",
      User: "alertmanager",
      Group: "alertmanager",
      ExecStart: "/usr/local/bin/alertmanager --config.file=/etc/prometheus/alertmanager.yml --storage.path=/var/lib/alertmanager --web.listen-address=:9093",
      Restart: "on-failure",
      RestartSec: "5",
    },
    Install: {
      WantedBy: "multi-user.target",
    },
  })
  triggers_reload true
  action :create
end

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

firewall_rule "prometheus alertmanager" do
  port 9093
  source "10.1.1.0/24"
  protocol :tcp
  command :allow
end