text: # This example code is in the Public Domain (or CC0 licensed, at your option.)
  
  # Unless required by applicable law or agreed to in writing, this
  # software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
  # CONDITIONS OF ANY KIND, either express or implied.
  
  # -*- coding: utf-8 -*-
  
  from __future__ import print_function, unicode_literals
  
  import os
  import re
  import socket
  import sys
  from builtins import input
  from threading import Event, Thread
  
  import netifaces
  import ttfw_idf
  
  # -----------  Config  ----------
  PORT = 3333
  INTERFACE = 'eth0'
  # -------------------------------
  
  
  def get_my_ip(type):
      for i in netifaces.ifaddresses(INTERFACE)[type]:
          return i['addr'].replace('%{}'.format(INTERFACE), '')
  
  
  class UdpServer:
  
      def __init__(self, port, family_addr, persist=False):
          self.port = port
          self.family_addr = family_addr
          self.socket = socket.socket(family_addr, socket.SOCK_DGRAM)
          self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
          self.socket.settimeout(60.0)
          self.shutdown = Event()
          self.persist = persist
  
      def __enter__(self):
          try:
              self.socket.bind(('', self.port))
          except socket.error as e:
              print('Bind failed:{}'.format(e))
              raise
  
          print('Starting server on port={} family_addr={}'.format(self.port, self.family_addr))
          self.server_thread = Thread(target=self.run_server)
          self.server_thread.start()
          return self
  
      def __exit__(self, exc_type, exc_value, traceback):
          if self.persist:
              sock = socket.socket(self.family_addr, socket.SOCK_DGRAM)
              sock.sendto(b'Stop', ('localhost', self.port))
              sock.close()
              self.shutdown.set()
          self.server_thread.join()
          self.socket.close()
  
      def run_server(self):
          while not self.shutdown.is_set():
              try:
                  data, addr = self.socket.recvfrom(1024)
                  if not data:
                      return
                  data = data.decode()
                  print('Reply[' + addr[0] + ':' + str(addr[1]) + '] - ' + data)
                  reply = 'OK: ' + data
                  self.socket.sendto(reply.encode(), addr)
              except socket.error as e:
                  print('Running server failed:{}'.format(e))
                  raise
              if not self.persist:
                  break
  
  
  @ttfw_idf.idf_example_test(env_tag='Example_WIFI_Protocols')
  def test_examples_protocol_socket_udpclient(env, extra_data):
      """
      steps:
        1. join AP
        2. have the board connect to the server
        3. send and receive data
      """
      dut1 = env.get_dut('udp_client', 'examples/protocols/sockets/udp_client', dut_class=ttfw_idf.ESP32DUT)
      # check and log bin size
      binary_file = os.path.join(dut1.app.binary_path, 'udp_client.bin')
      bin_size = os.path.getsize(binary_file)
      ttfw_idf.log_performance('udp_client_bin_size', '{}KB'.format(bin_size // 1024))
  
      # start test
      dut1.start_app()
  
      ipv4 = dut1.expect(re.compile(r' IPv4 address: ([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)'), timeout=30)[0]
      ipv6_r = r':'.join((r'[0-9a-fA-F]{4}',) * 8)    # expect all 8 octets from IPv6 (assumes it's printed in the long form)
      ipv6 = dut1.expect(re.compile(r' IPv6 address: ({})'.format(ipv6_r)), timeout=30)[0]
      print('Connected with IPv4={} and IPv6={}'.format(ipv4, ipv6))
  
      # test IPv4
      with UdpServer(PORT, socket.AF_INET):
          server_ip = get_my_ip(netifaces.AF_INET)
          print('Connect udp client to server IP={}'.format(server_ip))
          dut1.write(server_ip)
          dut1.expect(re.compile(r'OK: Message from ESP32'))
      # test IPv6
      with UdpServer(PORT, socket.AF_INET6):
          server_ip = get_my_ip(netifaces.AF_INET6)
          print('Connect udp client to server IP={}'.format(server_ip))
          dut1.write(server_ip)
          dut1.expect(re.compile(r'OK: Message from ESP32'))
  
  
  if __name__ == '__main__':
      if sys.argv[1:] and sys.argv[1].startswith('IPv'):     # if additional arguments provided:
          # Usage: example_test.py <IPv4|IPv6>
          family_addr = socket.AF_INET6 if sys.argv[1] == 'IPv6' else socket.AF_INET
          with UdpServer(PORT, family_addr, persist=True) as s:
              print(input('Press Enter stop the server...'))
      else:
          test_examples_protocol_socket_udpclient()
  