Rails solid_queue alive server livenessProbe readinessProbe kubernetes helper

solid_queue_alive.rb

class SolidQueueAliveServer
  def initialize(host: nil, port: nil, engine: nil, logger: nil)
    @host = host || "0.0.0.0"
    @port = port || 7433
    @engine = engine || "puma"
    @logger = logger || Rails.logger
  end

  def run!
    require "rackup"
    handler = Rackup::Handler.get(@engine)
    Signal.trap("TERM") { handler.shutdown }
    handler.run(self, Port: @port, Host: @host, AccessLog: [], Logger: @logger)
  end

  def alive?
    true
  end

  def call(_env)
    [
      alive? ? 200 : 500,
      {"Content-Type" => "application/json"},
      [
        {alive: alive?}.to_json
      ]
    ]
  end
end

SolidQueue.on_start do
  @server_pid = fork { SolidQueueAliveServer.new.run! }
end
SolidQueue.on_stop do
  Process.kill("TERM", @server_pid) unless @server_pid.nil?
  Process.wait(@server_pid) unless @server_pid.nil?
end