qthread1.py

from six.moves import queue as thqueue
import json
from Qt import QtCore


class DataRetrievalThread(QtCore.QThread):
    failed = QtCore.Signal(object)
    dataReady = QtCore.Signal(object)

    def __init__(self, job_queue=None, parent=None):
        super(DataRetrievalThread, self).__init__(parent=None)
        self.job_queue = job_queue or thqueue.Queue()
    def run(self):
        while not self.job_queue.empty():
            try:
                self.run_next_job()
            except Exception as e:
                self.failed.emit(str(e))
            finally:
                self.job_queue.task_done()

    def run_next_job(self):
        next_ = json.loads(self.job_queue.get())

        action = next_['action']
        data = next_['data']
        response = next_.copy()

        if action == 'action1':
            self.do_action1(data=data, response=response)

        if action == 'action2':
            self.do_action2(data=data, response=response)

        if action == 'action3':
            self.do_action3(data=data, response=response)

        if action == 'action3':
            self.do_action3(data=data, response=response)

        else:
            raise NotImplementedError('Action "{}" not implemented'
                                      .format(action))

        self.dataReady.emit(json.dumps(response))

qthread2.py

def requestData(self, action, data, callback=None):
    event = {'id': str(uuid.uuid4()),
             'data': data,
             'action': action,
             'callback': callback,
             'source': self._name}
    self.events[event['id']] = event

    serialized_event = event.copy()
    serialized_event.pop('callback')
    self.thread_queue.put(json.dumps(serialized_event))

    if not self.thread.isRunning() and self.thread_ready:
        self.thread.start()

    return event['id']


def onThreadJobFinished(self, event):
    if event['source'] != self._name:
        return

    orig_event = self.events[event['id']]

    if orig_event['callback']:
        orig_event['callback'](event)

    self.events[event['id']]['result'] = event['result']