Shield pending commands from cancellation

pytec/pytec/aioclient.py

@@ -74,12 +74,16 @@ class Client:
         chunk = await self._reader.readline()
         return chunk.decode('utf-8', errors='ignore')
 
+    async def _read_write(self, command):
+        self._writer.write(((" ".join(command)).strip() + "\n").encode('utf-8'))
+        await self._writer.drain()
+
+        return await self._read_line()
+
     async def _command(self, *command):
         async with self._command_lock:
-            self._writer.write(((" ".join(command)).strip() + "\n").encode('utf-8'))
-            await self._writer.drain()
-
-            line = await self._read_line()
+            # protect the read-write process from being cancelled midway
+            line = await asyncio.shield(self._read_write(command))
 
         response = json.loads(line)
         logging.debug(f"{command}: {response}")