Documentation
Examples
Queue

Queue

Outbound example: one extension calls another through the app. The caller hears hold music (or a message) until a queue slot is free, then we bridge them to the callee. Only one bridge at a time, so you keep control (e.g. one agent per queue).

Example Code

examples/queue.py
"""
Queue example.

One extension calls another via the app: the caller is held (music or message)
until a queue slot is free, then we bridge them to the callee. Only one
bridge at a time so you keep control (e.g. one agent per queue).
"""

import asyncio
import os

from genesis import Outbound, Session, Queue, Channel
from genesis.types import ChannelState

HOST = os.getenv("HOST", "0.0.0.0")
PORT = int(os.getenv("PORT", "9696"))
CALLEE = "user/1001"
HOLD_SOUND = os.getenv("HOLD_SOUND", "local_stream://moh")

queue = Queue()  # in-memory by default


async def handler(session: Session) -> None:
    if session.channel is None:
        return
    await session.channel.answer()
    await session.channel.playback(HOLD_SOUND, block=False)

    async with queue.slot("support"):
        callee = await Channel.create(session, CALLEE)
        await callee.wait(ChannelState.EXECUTE, timeout=30.0)
        await session.channel.bridge(callee)


async def main() -> None:
    server = Outbound(handler=handler, host=HOST, port=PORT)
    await server.start()


if __name__ == "__main__":
    asyncio.run(main())

Flow

FreeSWITCH sends the call

FreeSWITCH sends the call to your app (outbound socket).

Answer and play hold sound

We answer and start playing a hold sound (playback(..., block=False)), so the caller hears it while waiting.

Wait for a queue slot

The handler waits for a slot in the "support" queue (async with queue.slot("support")). If another call is already in the slot, this call waits (caller keeps hearing the hold sound).

Originate callee and bridge

When we get the slot, we originate the callee (Channel.create(session, CALLEE)), wait for them to answer, then bridge the caller to the callee. The bridge replaces the hold playback.

Release the slot

When the handler leaves the async with block, the slot is released and the next waiting caller can be served.

Running the Example

Start FreeSWITCH

Make sure FreeSWITCH is running (see Examples environment).

Run the queue example 

python examples/queue.py

Make test calls

  • You need two SIP clients: caller and callee (user/1001). See Examples environment (Docker includes MOH).
  • Call the number that hits this dialplan. You hear hold music until your turn, then you’re bridged to the callee.
  • Place a second call while the first is still connected: the second caller hears hold music until the first call ends.

View Logs

To see what’s happening in FreeSWITCH:

docker exec -it genesis-freeswitch fs_cli -x "show channels"
docker logs genesis-freeswitch -f

Related

IVRGroup Call