aioespnow send method produces error on broadcast send (ValueError: Send timeout on synch.)

[garykuipers]

Greetings: Relatively new to Micropython but knowledgeable about Python. Requesting assistance because I cannot find answers in my searches.

Here is the backtrace:
Traceback (most recent call last):
File "", line 1, in
File "main.py", line 70, in
File "uasyncio/core.py", line 1, in run
File "uasyncio/core.py", line 1, in run_until_complete
File "uasyncio/core.py", line 1, in run_until_complete
File "main.py", line 66, in main
File "uasyncio/funcs.py", line 1, in gather
File "uasyncio/core.py", line 1, in run_until_complete
File "main.py", line 49, in wait_peers
File "comms.py", line 39, in get_peers
File "comms.py", line 79, in register
File "comms.py", line 72, in send_message
ValueError: Send timeout on synch.

I am attaching the two files in the backtrace rather than presuming I know what to present. I appreciate your assistance.
main.py.txt this is the main.py
comms.py.txt this is the comms.py

I found aioespnow.py at https://github.com/glenn20/micropython/blob/espnow-g20/ports/esp32/modules/aioespnow.py
it is attached.

aioespnow.py.txt

The relevant section is:

22    async def asend(self, mac, msg=None, sync=None):
23        if msg is None:
24            msg, mac = mac, None  # If msg is None: swap mac and msg
25        yield uasyncio.core._io_queue.queue_write(self)
26        return self.send(mac, msg, sync)  # type: ignore

[karfas]

This is nothing special, I think.
You get a timeout when sending to to_mac[0] (which is most likely different from to_mac[1] printed) and you don't handle the resulting exception.
Maybe to_mac[0] is not started, disconnected, whatever ?

I don't have enough patience to analyze your whole program (this is your task, anyway).

    async def send_message(self, to_mac, msg: dict):
        msg_str = json.dumps(msg)
        print(f"Comms: send_message: to_mac={to_mac[1]} msg_str={msg_str}")
        await self.e.send(to_mac[0], msg_str.encode('ascii'))

[garykuipers]

That was a giant "DOH!" on my part. Thanks!

[glenn20]

@garykuipers Thanks for the report. As you can see from esp_espnow.c#L504 this exception "should not happen". The ESP-NOW software stack is meant to invoke the send_cb() function (which updates self->tx_responses) when a sent packet is acknowledged by the peer OR after no response has been received (which is usually invoked within 25ms or so). I have never seen this happen, but it is interesting to know that it can.

So, yes, as suggested by @karfas , best to just trap the exception and continue. I'll review my code to see if there is a better way to handle this now that I know it CAN occur or if there is some logic error on my part causing it to occur.

Oh - and if this is happening rarely, it should have little impact on your application, BUT if it happen frequently then you will be carrying the burden of the 250ms timeout whenever this occurs. If that is the case, give me some more details about your device and I will try to test.