scottyphillips
commented
2 years ago In the old days all the UDP functionality was very inefficient, and did not play nicely with Asyncio event loops at all. Basically I would fire a packet, listen for a response (which involved waiting for 3 seconds and pausing the entire Home Assistant) and then process the packet. It was fine when it was just me and my solo air conditioner but as more people started using the code with multiple devices, what was happening was that it was bogging Home Assistant down listening for messages.
As more people started using the Home Assistant component; and with multiple devices, I needed a better way of processing the packets in a manner that was asyncio friendly, and would work with Home Assistants event loop. To that end I used https://github.com/bashkirtsevich-llc/aioudp which provided a ready to use UDP service that was asyncio friendly. I rewrote the code in about a day.
What aio-udp-server allowed me to do was decouple the transmit and receive functionality, the receive is basically a listener that keeps the socket open at all times and can process any incoming packet that lands on port 3610. The transmit functionality works as UDP is expected to work, which is fire the message and forget. I use the TID to try to have some idea of whether or not packets are getting lost or are being received.
The drama we have is two fold:
- The aio-udp-server library is pretty basic and doesn't really have any coded functionality for listening to multicast.
- The listener (echonetMessageReceived) doesn't have much in the way of logic to process status change announcements.
To fix the first problem, we would probably have to rewrite aio-udp-server to enable a multicast listener (which should be possible, but would take some time). It would probably make sense to move aio-udp-serverinto pychonet and rewrite it as its not a particularly large library...
To fix the second problem we would have to update the listener logic to process any status change property announcements that are received on the multicast address.
Additionally, Home Assistant may or may not be able to listen to multicast; and that will really come down to the installation - if it's running in a Docker container for example it might not be possible to receive multicast packets (not that I am 100% sure).
There is some bare metal python3 socket code here for listening to multicast that I stole from stackoverflow:
import socket
import struct
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind(('', 4242))
mreq = struct.pack("=4sl", socket.inet_aton("224.51.105.104"), socket.INADDR_ANY)
sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
while True:
print sock.recv(10240)
nao-pon
ECHONET Lite can be notified of device changes by listening to UDP port 3610 at the multicast address 224.0.23.0.
For example, turning
0x90to on (0x41) / off (0x42) on a device with0x02-0x72, it will get following data.I think that you can use this to update the device changes immediately. But I'm not sure how to implement as server functionality in Python.
Do we have a chance to implement this?