add terminator helpers, add remote

carbus_async/remote/client.py

@@ -0,0 +1,42 @@
+from __future__ import annotations
+
+import asyncio
+import json
+from typing import Optional
+
+from carbus_async.device import CarBusDevice
+
+
+async def open_remote_device(
+    host: str,
+    port: int,
+    *,
+    serial: str,
+    password: str,
+    use_can: bool = True,
+    use_lin: bool = False,
+) -> CarBusDevice:
+    reader, writer = await asyncio.open_connection(host, port)
+
+    hello = {"role": "client", "serial": str(serial), "password": str(password)}
+    writer.write((json.dumps(hello) + "\n").encode("utf-8"))
+    await writer.drain()
+
+    line = await asyncio.wait_for(reader.readline(), timeout=10.0)
+    resp = json.loads(line.decode("utf-8", errors="ignore") or "{}")
+    if not resp.get("ok"):
+        writer.close()
+        try:
+            await writer.wait_closed()
+        except Exception:
+            pass
+        raise RuntimeError(f"relay refused client: {resp}")
+
+    dev = await CarBusDevice.open_stream(
+        reader,
+        writer,
+        logical_port=f"remote://{host}:{port}/{serial}",
+        use_can=use_can,
+        use_lin=use_lin,
+    )
+    return dev