fix(webui): suppress restart handshake noise

nanobot/channels/websocket.py

@@ -7,6 +7,7 @@ import email.utils
 import hmac
 import http
 import json
+import logging
 import mimetypes
 import re
 import secrets
@@ -116,6 +117,45 @@ def _host_for_url(host: str, port: int) -> str:
     return f"{host}:{port}"
 
 
+_OPENING_HANDSHAKE_FAILED_MESSAGE = "opening handshake failed"
+
+
+def _exception_chain_has_disconnect(exc: BaseException | None) -> bool:
+    seen: set[int] = set()
+    while exc is not None:
+        ident = id(exc)
+        if ident in seen:
+            return False
+        seen.add(ident)
+        if isinstance(exc, (
+            BrokenPipeError,
+            ConnectionAbortedError,
+            ConnectionResetError,
+            ConnectionClosed,
+        )):
+            return True
+        exc = exc.__cause__ or exc.__context__
+    return False
+
+
+class _WebSocketHandshakeNoiseFilter(logging.Filter):
+    """Suppress noisy restart-time handshakes where the client already disconnected."""
+
+    def filter(self, record: logging.LogRecord) -> bool:
+        if record.getMessage() != _OPENING_HANDSHAKE_FAILED_MESSAGE:
+            return True
+        exc_info = record.exc_info
+        exc = exc_info[1] if isinstance(exc_info, tuple) and len(exc_info) >= 2 else None
+        return not _exception_chain_has_disconnect(exc)
+
+
+def _websockets_server_logger() -> logging.Logger:
+    ws_logger = logging.getLogger("websockets.server")
+    if not any(isinstance(f, _WebSocketHandshakeNoiseFilter) for f in ws_logger.filters):
+        ws_logger.addFilter(_WebSocketHandshakeNoiseFilter())
+    return ws_logger
+
+
 class WebSocketConfig(Base):
     """WebSocket server channel configuration.
 
@@ -1239,6 +1279,7 @@ class WebSocketChannel(BaseChannel):
         from nanobot.utils.logging_bridge import redirect_lib_logging
 
         redirect_lib_logging("websockets", level="WARNING")
+        ws_logger = _websockets_server_logger()
 
         self._running = True
         self._stop_event = asyncio.Event()
@@ -1290,6 +1331,7 @@ class WebSocketChannel(BaseChannel):
                     max_size=self.config.max_message_bytes,
                     ping_interval=self.config.ping_interval_s,
                     ping_timeout=self.config.ping_timeout_s,
+                    logger=ws_logger,
                 )
                 with suppress(OSError):
                     path_obj.chmod(0o600)
@@ -1303,6 +1345,7 @@ class WebSocketChannel(BaseChannel):
                     ping_interval=self.config.ping_interval_s,
                     ping_timeout=self.config.ping_timeout_s,
                     ssl=ssl_context,
+                    logger=ws_logger,
                 )
             try:
                 assert self._stop_event is not None

tests/channels/test_websocket_channel.py

@@ -3,6 +3,7 @@
 import asyncio
 import functools
 import json
+import logging
 import time
 from typing import Any
 from unittest.mock import AsyncMock, MagicMock
@@ -16,6 +17,7 @@ from websockets.frames import Close
 from nanobot.bus.events import OUTBOUND_META_AGENT_UI, OutboundMessage
 from nanobot.bus.queue import MessageBus
 from nanobot.channels.websocket import (
+    _OPENING_HANDSHAKE_FAILED_MESSAGE,
     WebSocketChannel,
     WebSocketConfig,
     _is_valid_chat_id,
@@ -26,6 +28,7 @@ from nanobot.channels.websocket import (
     _parse_inbound_payload,
     _parse_query,
     _parse_request_path,
+    _WebSocketHandshakeNoiseFilter,
     publish_runtime_model_update,
 )
 from nanobot.config.loader import load_config, save_config
@@ -39,6 +42,18 @@ from nanobot.webui.settings_api import settings_payload, update_provider_setting
 _PORT = 29876
 
 
+def _log_record(message: str, exc: BaseException) -> logging.LogRecord:
+    return logging.LogRecord(
+        name="websockets.server",
+        level=logging.ERROR,
+        pathname=__file__,
+        lineno=1,
+        msg=message,
+        args=(),
+        exc_info=(type(exc), exc, exc.__traceback__),
+    )
+
+
 def _ch(bus: Any, **kw: Any) -> WebSocketChannel:
     cfg: dict[str, Any] = {
         "enabled": True,
@@ -113,6 +128,22 @@ def test_websocket_config_rejects_relative_unix_socket() -> None:
         WebSocketConfig(unix_socket_path="engine.sock")
 
 
+def test_websocket_handshake_noise_filter_suppresses_disconnects() -> None:
+    filter_ = _WebSocketHandshakeNoiseFilter()
+    wrapped = RuntimeError("wrapped")
+    wrapped.__cause__ = BrokenPipeError(32, "Broken pipe")
+
+    assert not filter_.filter(_log_record(_OPENING_HANDSHAKE_FAILED_MESSAGE, BrokenPipeError()))
+    assert not filter_.filter(_log_record(_OPENING_HANDSHAKE_FAILED_MESSAGE, wrapped))
+
+
+def test_websocket_handshake_noise_filter_keeps_real_errors() -> None:
+    filter_ = _WebSocketHandshakeNoiseFilter()
+
+    assert filter_.filter(_log_record(_OPENING_HANDSHAKE_FAILED_MESSAGE, RuntimeError("boom")))
+    assert filter_.filter(_log_record("connection handler failed", BrokenPipeError()))
+
+
 def test_parse_query_extracts_token_and_client_id() -> None:
     query = _parse_query("/?token=secret&client_id=u1")
     assert query.get("token") == ["secret"]