feat: improve handling of out of esp32 proxy connection slots (#56)

src/bleak_retry_connector/__init__.py

@@ -40,6 +40,7 @@
 # to run their cleanup callbacks or the
 # retry call will just fail in the same way.
 BLEAK_DBUS_BACKOFF_TIME = 0.25
+BLEAK_OUT_OF_SLOTS_BACKOFF_TIME = 1.5
 BLEAK_BACKOFF_TIME = 0.1
 
 
@@ -91,6 +92,8 @@
 
 DEVICE_MISSING_ERRORS = {"org.freedesktop.DBus.Error.UnknownObject"}
 
+OUT_OF_SLOTS_ERRORS = {"available connection", "connection slot"}
+
 # Currently the same as transient error
 ABORT_ERRORS = TRANSIENT_ERRORS
 
@@ -104,6 +107,11 @@
     "The device disappeared; " "Try restarting the scanner or moving the device closer"
 )
 
+OUT_OF_SLOTS_ADVICE = (
+    "The proxy/adapter is out of connection slots; "
+    "Add additional proxies near this device"
+)
+
 
 class BleakNotFoundError(BleakError):
     """The device was not found."""
@@ -117,6 +125,10 @@ class BleakAbortedError(BleakError):
     """The connection was aborted."""
 
 
+class BleakOutOfConnectionSlotsError(BleakError):
+    """The proxy/adapter is out of connection slots."""
+
+
 class BleakClientWithServiceCache(BleakClient):
     """A BleakClient that implements service caching."""
 
@@ -183,6 +195,8 @@ def address_to_bluez_path(address: str, adapter: str | None = None) -> str:
 
 def calculate_backoff_time(exc: Exception) -> float:
     """Calculate the backoff time based on the exception."""
+    if isinstance(exc, BleakOutOfConnectionSlotsError):
+        return BLEAK_OUT_OF_SLOTS_BACKOFF_TIME
     if isinstance(
         exc, (BleakDBusError, EOFError, asyncio.TimeoutError, BrokenPipeError)
     ):
@@ -431,14 +445,15 @@ def _raise_if_needed(name: str, description: str, exc: Exception) -> None:
         # Sure would be nice if bleak gave us typed exceptions
         if isinstance(exc, asyncio.TimeoutError) or "not found" in str(exc):
             raise BleakNotFoundError(msg) from exc
-        if isinstance(exc, BleakError) and any(
-            error in str(exc) for error in ABORT_ERRORS
-        ):
-            raise BleakAbortedError(f"{msg}: {ABORT_ADVICE}") from exc
-        if isinstance(exc, BleakError) and any(
-            error in str(exc) for error in DEVICE_MISSING_ERRORS
-        ):
-            raise BleakNotFoundError(f"{msg}: {DEVICE_MISSING_ADVICE}") from exc
+        if isinstance(exc, BleakError):
+            if any(error in str(exc) for error in ABORT_ERRORS):
+                raise BleakAbortedError(f"{msg}: {ABORT_ADVICE}") from exc
+            if any(error in str(exc) for error in DEVICE_MISSING_ERRORS):
+                raise BleakNotFoundError(f"{msg}: {DEVICE_MISSING_ADVICE}") from exc
+            if any(error in str(exc) for error in OUT_OF_SLOTS_ERRORS):
+                raise BleakOutOfConnectionSlotsError(
+                    f"{msg}: {OUT_OF_SLOTS_ADVICE}"
+                ) from exc
         raise BleakConnectionError(msg) from exc
 
     create_client = True

tests/test_init.py

@@ -13,11 +13,13 @@
 from bleak_retry_connector import (
     BLEAK_BACKOFF_TIME,
     BLEAK_DBUS_BACKOFF_TIME,
+    BLEAK_OUT_OF_SLOTS_BACKOFF_TIME,
     MAX_TRANSIENT_ERRORS,
     BleakAbortedError,
     BleakClientWithServiceCache,
     BleakConnectionError,
     BleakNotFoundError,
+    BleakOutOfConnectionSlotsError,
     ble_device_has_changed,
     calculate_backoff_time,
     establish_connection,
@@ -434,6 +436,37 @@ async def disconnect(self, *args, **kwargs):
     )
 
 
+@pytest.mark.asyncio
+async def test_establish_connection_out_of_slots_advice():
+    class FakeBleakClient(BleakClient):
+        def __init__(self, *args, **kwargs):
+            pass
+
+        async def connect(self, *args, **kwargs):
+            raise BleakError("out of connection slots")
+
+        async def disconnect(self, *args, **kwargs):
+            pass
+
+    try:
+        await establish_connection(
+            FakeBleakClient,
+            BLEDevice("aa:bb:cc:dd:ee:ff", "name", {"path": "/dev/1"}),
+            "test",
+        )
+    except BleakError as e:
+        exc = e
+
+    assert isinstance(exc, BleakOutOfConnectionSlotsError)
+    assert str(exc) == (
+        "test - /dev/1: "
+        "Failed to connect: "
+        "out of connection slots: "
+        "The proxy/adapter is out of connection slots; "
+        "Add additional proxies near this device"
+    )
+
+
 @pytest.mark.asyncio
 async def test_device_disappeared_error():
     class FakeBleakClient(BleakClient):
@@ -1443,6 +1476,10 @@ def test_calculate_backoff_time():
         calculate_backoff_time(BleakDBusError(MagicMock(), MagicMock()))
         == BLEAK_DBUS_BACKOFF_TIME
     )
+    assert (
+        calculate_backoff_time(BleakOutOfConnectionSlotsError())
+        == BLEAK_OUT_OF_SLOTS_BACKOFF_TIME
+    )
 
 
 @pytest.mark.asyncio