Make failure to increase the recv buffer size non-fatal

We now try to set the buffer to
2097152, 1048576, 524288, 262144, 131072

before giving up and logging a warning

aioesphomeapi/connection.pxd

@@ -152,3 +152,5 @@ cdef class APIConnection:
     cdef void _set_fatal_exception_if_unset(self, Exception err)
 
     cdef void _register_internal_message_handlers(self)
+
+    cdef void _increase_recv_buffer_size(self)

aioesphomeapi/connection.py

@@ -62,7 +62,8 @@ else:
 
 _LOGGER = logging.getLogger(__name__)
 
-BUFFER_SIZE = 1024 * 1024 * 2  # Set buffer limit to 2MB
+PREFERRED_BUFFER_SIZE = 2097152  # Set buffer limit to 2MB
+MIN_BUFFER_SIZE = 131072  # Minimum buffer size to use
 
 DISCONNECT_REQUEST_MESSAGE = DisconnectRequest()
 DISCONNECT_RESPONSE_MESSAGES = (DisconnectResponse(),)
@@ -384,9 +385,7 @@ class APIConnection:
         self._socket = sock
         sock.setblocking(False)
         sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
-        # Try to reduce the pressure on esphome device as it measures
-        # ram in bytes and we measure ram in megabytes.
-        sock.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, BUFFER_SIZE)
+        self._increase_recv_buffer_size()
         self.connected_address = sock.getpeername()[0]
 
         if self._debug_enabled:
@@ -397,6 +396,32 @@ class APIConnection:
                 self._params.port,
             )
 
+    def _increase_recv_buffer_size(self) -> None:
+        """Increase the recv buffer size."""
+        if TYPE_CHECKING:
+            assert self._socket is not None
+        new_buffer_size = PREFERRED_BUFFER_SIZE
+        while True:
+            # Try to reduce the pressure on ESPHome device as it measures
+            # ram in bytes and we measure ram in megabytes.
+            try:
+                self._socket.setsockopt(
+                    socket.SOL_SOCKET, socket.SO_RCVBUF, new_buffer_size
+                )
+                return
+            except OSError as err:
+                if new_buffer_size <= MIN_BUFFER_SIZE:
+                    _LOGGER.warning(
+                        "%s: Unable to increase the socket receive buffer size to %s; "
+                        "The connection may not be unstable if the ESPHome device "
+                        "sends at volume (ex. a Bluetooth proxy or camera): %s",
+                        self.log_name,
+                        new_buffer_size,
+                        err,
+                    )
+                    return
+                new_buffer_size //= 2
+
     async def _connect_init_frame_helper(self) -> None:
         """Step 3 in connect process: initialize the frame helper and init read loop."""
         fh: APIPlaintextFrameHelper | APINoiseFrameHelper

tests/test_connection.py

@@ -2,10 +2,11 @@ from __future__ import annotations
 
 import asyncio
 import logging
+import socket
 from datetime import timedelta
 from functools import partial
 from typing import Callable, cast
-from unittest.mock import AsyncMock, MagicMock, call, patch
+from unittest.mock import AsyncMock, MagicMock, call, create_autospec, patch
 
 import pytest
 from google.protobuf import message
@@ -236,6 +237,97 @@ async def test_start_connection_socket_error(
     await asyncio.sleep(0)
 
 
+@pytest.mark.asyncio
+async def test_start_connection_cannot_increase_recv_buffer(
+    conn: APIConnection,
+    resolve_host,
+    aiohappyeyeballs_start_connection: MagicMock,
+    caplog: pytest.LogCaptureFixture,
+):
+    """Test failing to increase the recv buffer."""
+    loop = asyncio.get_event_loop()
+    transport = MagicMock()
+    connected = asyncio.Event()
+    tried_sizes = []
+
+    def _setsockopt(*args, **kwargs):
+        if args[0] == socket.SOL_SOCKET and args[1] == socket.SO_RCVBUF:
+            size = args[2]
+            tried_sizes.append(size)
+            raise OSError("Socket error")
+
+    mock_socket: socket.socket = create_autospec(
+        socket.socket, spec_set=True, instance=True, name="bad_buffer_socket"
+    )
+    mock_socket.type = socket.SOCK_STREAM
+    mock_socket.fileno.return_value = 1
+    mock_socket.getpeername.return_value = ("10.0.0.512", 323)
+    mock_socket.setsockopt = _setsockopt
+    mock_socket.sendmsg.side_effect = OSError("Socket error")
+    aiohappyeyeballs_start_connection.return_value = mock_socket
+
+    with patch.object(
+        loop,
+        "create_connection",
+        side_effect=partial(_create_mock_transport_protocol, transport, connected),
+    ):
+        connect_task = asyncio.create_task(connect(conn, login=False))
+        await asyncio.sleep(0)
+        await connected.wait()
+        protocol = conn._frame_helper
+        send_plaintext_hello(protocol)
+        await connect_task
+
+    assert "Unable to increase the socket receive buffer size to 131072" in caplog.text
+    assert tried_sizes == [2097152, 1048576, 524288, 262144, 131072]
+
+
+@pytest.mark.asyncio
+async def test_start_connection_can_only_increase_buffer_size_to_262144(
+    conn: APIConnection,
+    resolve_host,
+    aiohappyeyeballs_start_connection: MagicMock,
+    caplog: pytest.LogCaptureFixture,
+):
+    """Test the receive buffer can only be increased to 262144."""
+    loop = asyncio.get_event_loop()
+    transport = MagicMock()
+    connected = asyncio.Event()
+    tried_sizes = []
+
+    def _setsockopt(*args, **kwargs):
+        if args[0] == socket.SOL_SOCKET and args[1] == socket.SO_RCVBUF:
+            size = args[2]
+            tried_sizes.append(size)
+            if size != 262144:
+                raise OSError("Socket error")
+
+    mock_socket: socket.socket = create_autospec(
+        socket.socket, spec_set=True, instance=True, name="bad_buffer_socket"
+    )
+    mock_socket.type = socket.SOCK_STREAM
+    mock_socket.fileno.return_value = 1
+    mock_socket.getpeername.return_value = ("10.0.0.512", 323)
+    mock_socket.setsockopt = _setsockopt
+    mock_socket.sendmsg.side_effect = OSError("Socket error")
+    aiohappyeyeballs_start_connection.return_value = mock_socket
+
+    with patch.object(
+        loop,
+        "create_connection",
+        side_effect=partial(_create_mock_transport_protocol, transport, connected),
+    ):
+        connect_task = asyncio.create_task(connect(conn, login=False))
+        await asyncio.sleep(0)
+        await connected.wait()
+        protocol = conn._frame_helper
+        send_plaintext_hello(protocol)
+        await connect_task
+
+    assert "Unable to increase the socket receive buffer size" not in caplog.text
+    assert tried_sizes == [2097152, 1048576, 524288, 262144]
+
+
 @pytest.mark.asyncio
 async def test_start_connection_times_out(
     conn: APIConnection, resolve_host, aiohappyeyeballs_start_connection