Add serial connection

Expand dependancy list

rename aioserial_instance to stream

pyproject.toml

@@ -11,6 +11,7 @@ classifiers = [
 ]
 description = "Control system agnostic framework for building Device support in Python that will work for both EPICS and Tango"
 dependencies = [
+    "aioserial",
     "numpy",
     "pydantic",
     "pvi~=0.8.1",

src/fastcs/connections/serial_connection.py

@@ -0,0 +1,52 @@
+import asyncio
+from dataclasses import dataclass
+
+import aioserial
+
+
+class NotOpenedError(Exception):
+    pass
+
+
+@dataclass
+class SerialConnectionSettings:
+    port: str
+    baud: int = 115200
+
+
+class SerialConnection:
+    def __init__(self):
+        self.stream = None
+        self._lock = asyncio.Lock()
+
+    async def connect(self, settings: SerialConnectionSettings) -> None:
+        self.stream = aioserial.AioSerial(port=settings.port, baudrate=settings.baud)
+
+    def ensure_open(self):
+        if self.stream is None:
+            raise NotOpenedError(
+                "Need to call connect() before using SerialConnection."
+            )
+
+    async def send_command(self, message: bytes) -> None:
+        async with self._lock:
+            self.ensure_open()
+            await self._send_message(message)
+
+    async def send_query(self, message: bytes, response_size: int) -> bytes:
+        async with self._lock:
+            self.ensure_open()
+            await self._send_message(message)
+            return await self._receive_response(response_size)
+
+    async def close(self) -> None:
+        async with self._lock:
+            self.ensure_open()
+            self.stream.close()
+            self.stream = None
+
+    async def _send_message(self, message):
+        await self.stream.write_async(message)
+
+    async def _receive_response(self, size):
+        return await self.stream.read_async(size)