text: # -*- coding: utf-8 -*-
  # Copyright (c) 2018-2020 Christiaan Frans Rademan <chris@fwiw.co.za>. David Kruger.
  # All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are met:
  #
  # * Redistributions of source code must retain the above copyright notice, this
  #   list of conditions and the following disclaimer.
  #
  # * Redistributions in binary form must reproduce the above copyright notice,
  #   this list of conditions and the following disclaimer in the documentation
  #   and/or other materials provided with the distribution.
  #
  # * Neither the name of the copyright holders nor the names of its
  #   contributors may be used to endorse or promote products derived from
  #   this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  # ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  # THE POSSIBILITY OF SUCH DAMAGE.
  import functools
  import time
  from queue import Queue
  from multiprocessing import current_process
  
  from luxon import g
  from luxon.core.logger import GetLogger
  from luxon.utils.rmq import Rmq
  from luxon.exceptions import MessageBusError
  from luxon.utils.multiproc import ProcessManager
  from luxon.utils.multithread import ThreadManager
  
  log = GetLogger(__name__)
  
  
  def rmq():
      kwargs = g.app.config.kwargs('rabbitmq')
      return Rmq(**kwargs)
  
  
  class MBClient(object):
      def __init__(self, queue):
          self._queue = queue
          self._rmq = None
  
      def send(self, func, msg):
          if self._rmq is not None:
              msg = {'type': func,
                     'msg': msg}
              self._rmq.distribute(self._queue, **msg)
          else:
              raise MessageBusError('MBClient connection closed' +
                                    '/ use enter context')
  
      def __enter__(self):
          self._rmq = rmq()
          return self
  
      def __exit__(self, type, value, traceback):
          self._rmq.close()
  
      def close(self):
          if self._rmq is not None:
              self._rmq.close()
  
  
  class MBServer(object):
      def __init__(self, queue, funcs, procs=1, threads=1, process_manager=None,
                   retry=60):
          self._funcs = funcs
          self._procs = procs
          self._threads = threads
          self._queue = queue
          self._retry = retry
          if process_manager:
              self._pm = process_manager
              self._pmi = False
          else:
              self._pm = ProcessManager()
              self._pmi = True
  
      def start(self):
          for mp in range(self._procs):
              self._pm.new(self._messagebus_proc,
                           'MB-%s' % (mp+1,),
                           restart=True)
  
          if self._pmi:
              self._pm.start()
  
      def _messagebus_proc(self):
          proc_name = current_process().name
          tm = ThreadManager()
          queue = Queue(maxsize=self._threads * 2)
  
          def ack_message(ch, delivery_tag):
              if ch.is_open:
                  ch.basic_ack(delivery_tag=delivery_tag)
              else:
                  pass
  
          def reject_message(ch, delivery_tag, requeue=False):
              if ch.is_open:
                  ch.basic_reject(delivery_tag=delivery_tag,
                                  requeue=requeue)
              else:
                  pass
  
          def _messagebus_thread():
              while True:
                  connection, ch, method, properties, msg = queue.get()
                  msg_type = msg.get('type')
                  message = msg.get('msg')
                  dtag = method.delivery_tag
                  if msg_type in self._funcs:
                      if message is not None:
                          try:
                              if self._funcs[msg_type](message):
                                  msg_ack = functools.partial(ack_message, ch,
                                                              dtag)
                                  connection.add_callback_threadsafe(msg_ack)
                              else:
                                  msg_ack = functools.partial(reject_message, ch,
                                                              dtag,
                                                              False)
                                  connection.add_callback_threadsafe(msg_ack)
                          except Exception as e:
                              log.critical('Message failed to process' +
                                           ' type %s' % msg_type +
                                           ': Thread ended due to Exception'
                                           ' (%s)' % e)
                              log.critical('Sleeping %ss before re-queueing and'
                                           ' re-raising' % self._retry)
                              time.sleep(self._retry)
                              msg_ack = functools.partial(reject_message, ch,
                                                          dtag,
                                                          True)
                              connection.add_callback_threadsafe(msg_ack)
                              # Reraising so that we can get the full Traceback
                              # to see what caused the thread to end.
                              raise
                      else:
                          msg_ack = functools.partial(reject_message, ch,
                                                      method.delivery_tag,
                                                      False)
                          connection.add_callback_threadsafe(msg_ack)
                          log.critical('Message failed to process' +
                                       ' type %s' % msg_type +
                                       ' with empty body')
                  else:
                      msg_ack = functools.partial(reject_message, ch,
                                                  method.delivery_tag,
                                                  False)
                      connection.add_callback_threadsafe(msg_ack)
                      log.critical('Message failed to process' +
                                   ' unknown func/type %s' % msg_type)
  
          def _thread_receiver():
              def callback(connection, ch, method, properties, msg):
                  queue.put((connection, ch, method, properties, msg))
  
              with rmq() as mb:
                  mb.receiver(self._queue, callback,
                              acks=False, prefetch=self._threads)
  
          tm.new(_thread_receiver, '%s-Receiver', restart=True)
          for thread in range(self._threads):
              tm.new(_messagebus_thread,
                     '%s-%s' % (proc_name,
                                thread+1,),
                     restart=True)
          tm.start()
  