Hands-On: Vehicle Service Mesh

#!/usr/bin/env python3
"""Bridge SOME/IP SpeedService events to Kuksa data broker."""

import asyncio
import struct
import socket
from kuksa_client.grpc import VSSClient, Datapoint

SOMEIP_MULTICAST = "239.192.255.251"
SOMEIP_PORT      = 30490  # SOME/IP SD port
SPEED_SERVICE_ID = 0x0A01
SPEED_EVENT_ID   = 0x0001

def parse_someip_speed(data: bytes) -> float:
    """Parse SOME/IP payload: 4-byte float (big-endian)."""
    if len(data) >= 4:
        return struct.unpack(">f", data[:4])[0]
    return 0.0

async def bridge():
    # UDP socket for SOME/IP multicast receive
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sock.bind(("", SOMEIP_PORT))
    mreq = struct.pack("4sL", socket.inet_aton(SOMEIP_MULTICAST),
                       socket.INADDR_ANY)
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
    sock.setblocking(False)

    loop = asyncio.get_event_loop()

    async with VSSClient("127.0.0.1", 55555) as kuksa:
        print("SOME/IP -> Kuksa bridge active")
        while True:
            try:
                data, _ = await loop.sock_recv(sock, 1024)
                # SOME/IP header is 16 bytes; payload starts at byte 16
                service_id = struct.unpack(">H", data[0:2])[0]
                event_id   = struct.unpack(">H", data[2:4])[0]
                if service_id == SPEED_SERVICE_ID and event_id == SPEED_EVENT_ID:
                    speed = parse_someip_speed(data[16:])
                    await kuksa.set_current_values({
                        "Vehicle.Speed": Datapoint(speed)
                    })
            except Exception:
                await asyncio.sleep(0.001)

asyncio.run(bridge())