Class: Hatchet::WorkerRuntime::HealthCheck

Inherits:
Object
  • Object
show all
Defined in:
lib/hatchet/worker/health_check.rb

Overview

Simple HTTP health check server using raw TCPServer.

WEBrick was removed from Ruby’s default gems in Ruby 3.4+, so we use a raw TCPServer with minimal HTTP response to avoid adding a dependency.

Examples:

health = HealthCheck.new(port: 8001, logger: logger)
health.start  # runs in a background thread
health.stop

Instance Method Summary collapse

Constructor Details

#initialize(port:, logger:) ⇒ HealthCheck

Returns a new instance of HealthCheck.

Parameters:

  • port (Integer) —

    Port to listen on

  • logger (Logger) —

    Logger instance



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# File 'lib/hatchet/worker/health_check.rb', line 19

def initialize(port:, logger:)
  @port = port
  @logger = logger
  @running = false
  @thread = nil
  @server = nil
end

Instance Method Details

#running? ⇒ Boolean

Check if the server is running

Returns:

  • (Boolean) 


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# File 'lib/hatchet/worker/health_check.rb', line 83

def running?
  @running && @thread&.alive?
end

#start ⇒ Object

Start the health check server in a background thread



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# File 'lib/hatchet/worker/health_check.rb', line 28

def start
  @running = true

  @thread = Thread.new do
    @server = TCPServer.new("0.0.0.0", @port)
    @logger.info("Health check server listening on port #{@port}")

    loop do
      break unless @running

      begin
        client = @server.accept_nonblock
        client.gets # Read the request line

        response_body = "OK"
        response = "HTTP/1.1 200 OK\r\n" \
                   "Content-Type: text/plain\r\n" \
                   "Content-Length: #{response_body.length}\r\n" \
                   "Connection: close\r\n" \
                   "\r\n" \
                   "#{response_body}"

        client.print response
        client.close
      rescue IO::WaitReadable
        @server.wait_readable(1)
        retry if @running
      rescue StandardError => e
        @logger.debug("Health check error: #{e.message}") if @running
      end
    end
  rescue StandardError => e
    @logger.error("Health check server error: #{e.message}")
  ensure
    begin
      @server&.close
    rescue StandardError
      nil
    end
  end
end

#stop ⇒ Object

Stop the health check server



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# File 'lib/hatchet/worker/health_check.rb', line 71

def stop
  @running = false
  begin
    @server&.close
  rescue StandardError
    nil
  end
  @thread&.join(5)
end