Restart pipeline with Python on Error

[jack]

Hello !

I would like to restart a very simple pipeline on error using Python.
I tried but I failed.

My pipeline :

pipeline = Gst.parse_launch('souphttpsrc name=toto location=
http://stream.p-node.org/billiejean.mp3 ! '
                            'decodebin ! '
                            'audioconvert ! '
                            'audioresample ! '
                            'autoaudiosink')


My fist attempt was :

bus.connect("sync-message::error", _on_sync_bus_message_error)
def _on_sync_bus_message_error(bus, message):
    print(f'Error for stream', bus, message)
    print('Restarting')
    pipeline.set_state(Gst.State.NULL)
    pipeline.set_state(Gst.State.PLAYING)

Then i get :

(python:903853): GStreamer-WARNING **: 21:07:57.021: 
Trying to join task 0x166a290 from its thread would deadlock.
You cannot change the state of an element from its streaming
thread. Use g_idle_add() or post a GstMessage on the bus to
schedule the state change from the main thread.


OK, so let's go with "post a GstMessage on the bus to
schedule the state change from the main thread"

Here my second attempt :

bus.connect("sync-message::error", _on_sync_bus_message_error)
def _on_sync_bus_message_error(bus, message):
    print(f'Error for stream', bus, message)
    print('Restarting')
    custom_structure = Gst.Structure.new_empty("iserror")
    custom_message = Gst.Message.new_application(None,
custom_structure)
    bus.post(custom_message)  # here i post message on the bus...


Then I have a loop while to get message on the bus :

while True:
    try:
        message = bus.timed_pop(Gst.SECOND)
        if message == None:
            pass
        elif message.type == Gst.MessageType.APPLICATION:
            if message.get_structure().get_name() == "iserror":
                print('There is an error...')
                pipeline.set_state(Gst.State.NULL)
                pipeline.set_state(Gst.State.PLAYING)
    except KeyboardInterrupt:
        break

I was expecting to have my pipeline to restart but unfortnutely it
didn't.

What is the next step to to restart my pipeline ?
Best!
++

Jack