Raise a proper error when the bridge can't be reached

aiocomfoconnect/bridge.py

@@ -16,6 +16,7 @@
 from .const import VENTILATION_UNIT_PRODUCT_IDS
 from .exceptions import (
     AioComfoConnectNotConnected,
+    AioComfoConnectNotReachable,
     AioComfoConnectTimeout,
     ComfoConnectBadRequest,
     ComfoConnectError,
@@ -189,8 +190,13 @@ async def _open_connection(self, uuid: str):
         try:
             self._reader, self._writer = await asyncio.wait_for(asyncio.open_connection(self.host, self.PORT), TIMEOUT)
         except asyncio.TimeoutError as exc:
+            # Keep this before OSError, since TimeoutError is a subclass of it.
             _LOGGER.warning("Timeout while connecting to bridge %s", self.host)
             raise AioComfoConnectTimeout("Timeout while connecting to bridge") from exc
+        except OSError as exc:
+            # The bridge refused the connection, is gone from the network, or its hostname doesn't resolve.
+            _LOGGER.warning("Could not connect to bridge %s: %s", self.host, exc)
+            raise AioComfoConnectNotReachable(f"Could not connect to bridge: {exc}") from exc
 
         self._reference = itertools.count(1)
         self._local_uuid = uuid

aiocomfoconnect/comfoconnect.py

@@ -31,6 +31,7 @@
 )
 from aiocomfoconnect.exceptions import (
     AioComfoConnectNotConnected,
+    AioComfoConnectNotReachable,
     AioComfoConnectTimeout,
     ComfoConnectNotAllowed,
     VentilationUnitNotFoundException,
@@ -180,6 +181,10 @@ async def _reconnect_loop(self, uuid: str):
                 _LOGGER.warning("Connection timeout, retrying in 5 seconds...")
                 await asyncio.sleep(5)
 
+            except AioComfoConnectNotReachable as exc:
+                _LOGGER.warning("%s. Retrying in 5 seconds...", exc)
+                await asyncio.sleep(5)
+
             except VentilationUnitNotFoundException as exc:
                 _LOGGER.warning("%s, retrying in 5 seconds...", exc)
                 await asyncio.sleep(5)

aiocomfoconnect/exceptions.py

@@ -50,6 +50,10 @@ class AioComfoConnectTimeout(Exception):
     """An error occurred because the bridge didn't reply in time."""
 
 
+class AioComfoConnectNotReachable(Exception):
+    """An error occurred because the bridge could not be reached, for example when it moved to another address."""
+
+
 class BridgeNotFoundException(Exception):
     """Exception raised when no bridge is found."""
 

tests/test_bridge.py

@@ -1,6 +1,7 @@
 """Tests for the Bridge class."""
 
 import asyncio
+import socket
 from unittest.mock import AsyncMock, MagicMock, Mock, patch
 
 import pytest
@@ -14,6 +15,7 @@
 
 from aiocomfoconnect.exceptions import (
     AioComfoConnectNotConnected,
+    AioComfoConnectNotReachable,
     AioComfoConnectTimeout,
     ComfoConnectNotAllowed,
     VentilationUnitNotFoundException,
@@ -151,6 +153,26 @@ async def timeout_coro(*args, **kwargs):
                 await bridge.connect(LOCAL_UUID)
         assert not bridge.is_connected()
 
+    @pytest.mark.asyncio
+    @pytest.mark.parametrize(
+        "error",
+        [
+            OSError(113, "No route to host"),
+            ConnectionRefusedError(111, "Connection refused"),
+            socket.gaierror("Name or service not known"),
+        ],
+    )
+    async def test_connect_not_reachable(self, bridge, error):
+        """Test that a bridge we can't reach doesn't raise a bare OSError."""
+
+        async def error_coro(*args, **kwargs):
+            raise error
+
+        with patch("asyncio.open_connection", side_effect=error_coro):
+            with pytest.raises(AioComfoConnectNotReachable, match="Could not connect to bridge"):
+                await bridge.connect(LOCAL_UUID)
+        assert not bridge.is_connected()
+
     @pytest.mark.asyncio
     async def test_connect_already_connected(self, bridge, mock_connection):
         """Test connecting when already connected."""