[Freeswitch-users] Python-ESL: ESLconnection.execute() blocked when handling channel_park under thread

[Mohd Kamal Bin Mustafa]

I have this python code:-

import time
import json
import logging
import threading

from freeswitchESL import ESL

class EventThread(threading.Thread):
    def __init__(self, target, args):
        super(EventThread, self).__init__()
        self.target = target
        self.args = args

    def run(self):
        print("Running target")
        self.target(*self.args)

def on_channel_park(e):
    uuid = e.getHeader('Unique-ID')
    print("Ringing")
    conn.execute('ring_ready ', '', uuid)
    conn.execute('sleep', '5500', uuid)
    conn.execute('answer', '', uuid)
    print("answered, playing media ...")
    media_url = 'http://www.noiseaddicts.com/samples_1w72b820/17.mp3'
    resp = conn.execute("playback", media_url, uuid)
    print(resp.getHeader("Reply-Text"))
    print("playback done")
    print(resp)

if __name__ == '__main__':
    conn = ESL.ESLconnection('127.0.0.1', '8021', 'mypass')
    conn.events('plain', 'all')
    while True:
        e = conn.recvEvent()
        uuid = e.getHeader('Unique-ID')
        events_message = json.loads(e.serialize('json'))
        event_name = events_message['Event-Name'].lower()
        method_name = 'on_%s' % event_name
        print(method_name)

        if event_name == 'channel_park':
            print("spawning thread")
            t = EventThread(on_channel_park, args=(e,))
            t.start()

        if event_name == 'playback_stop':
            conn.execute("hangup", "", uuid)
            print("Hanging up")

Above, the code will stuck at conn.execute('ring_ready ', '', uuid) in
on_channel_park(). It never went pass through until I hangup the call.
In freeswitch log, it stopped at executing park().

But if I moved ring_ready, sleep, answer outside of the thread it will
work, i.e I can hear a playback:-

def on_channel_park(e):
    uuid = e.getHeader('Unique-ID')
    print("answered, playing media ...")
    media_url = 'http://www.noiseaddicts.com/samples_1w72b820/17.mp3'
    resp = conn.execute("playback", media_url, uuid)
    print(resp.getHeader("Reply-Text"))
    print("playback done")
    print(resp)

if __name__ == '__main__':
    conn = ESL.ESLconnection('127.0.0.1', '8021', 'mypass')
    conn.events('plain', 'all')
    while True:
        e = conn.recvEvent()
        uuid = e.getHeader('Unique-ID')
        events_message = json.loads(e.serialize('json'))
        event_name = events_message['Event-Name'].lower()
        method_name = 'on_%s' % event_name
        print(method_name)

        if event_name == 'channel_park':
            print("Ringing")
            conn.execute('ring_ready ', '', uuid)
            conn.execute('sleep', '5500', uuid)
            conn.execute('answer', '', uuid)
            print("spawning thread")
            t = EventThread(on_channel_park, args=(e,))
            t.start()

Any idea why this happen ?