fix: prevent infrastructure logs from flooding webhook JSONL files (#1035) (#1037)

## Summary
- Only attach `JsonLogHandler` to the main webhook logger, not
infrastructure loggers (mcp_server, logs_server)
- Filter infrastructure noise entries in log viewer streaming
- Add tests for logging separation and noise filtering

## Problem
Infrastructure loggers (MCP server, log viewer) were writing to
`webhooks_*.json` via `JsonLogHandler`, flooding the file with
context-less entries. When querying via MCP, these noise entries were
the most recent (generated by the MCP call itself), drowning out actual
webhook data and returning 0 useful results.

## Changes
| File | Change |
|---|---|
| `webhook_server/utils/helpers.py` | Only attach `JsonLogHandler` when
no explicit `log_file_name` is provided |
| `webhook_server/web/log_viewer.py` | Add `_is_infrastructure_noise()`
filter for streaming, skip entries from infra loggers with no webhook
context |
| `webhook_server/tests/test_logging_separation.py` | **NEW** — 9 tests
for handler attachment and noise filtering |

## Test plan
- [x] All 1425 tests pass, 90.37% coverage
- [ ] Deploy and verify MCP queries return webhook data
- [ ] Verify `mcpl call github-webhook-logs-myakove get_log_entries
'{"limit": 5}'` returns entries

Closes #1035

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

## Release Notes

* **New Features**
* Webhook log queries now automatically exclude infrastructure and
system noise entries that are not associated with a specific webhook,
providing cleaner and more focused results.

* **Tests**
* Added comprehensive test coverage for logging separation and
infrastructure noise filtering functionality.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: myakove

webhook_server/tests/test_logging_separation.py

@@ -1,11 +1,15 @@
+import datetime
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 
 import webhook_server.app
 from webhook_server.app import get_log_viewer_controller, lifespan
 from webhook_server.libs.config import Config
-from webhook_server.utils.helpers import get_log_file_path
+from webhook_server.libs.log_parser import LogEntry
+from webhook_server.utils.helpers import get_log_file_path, get_logger_with_params
+from webhook_server.utils.json_log_handler import JsonLogHandler
+from webhook_server.web.log_viewer import LogViewerController
 
 
 def test_get_log_file_path_absolute():
@@ -18,8 +22,8 @@ def test_get_log_file_path_absolute():
 def test_get_log_file_path_relative():
     config = MagicMock(spec=Config)
     config.data_dir = "/tmp/data"
-    # Mock os.makedirs to avoid filesystem side effects
-    with patch("os.makedirs") as mock_makedirs:
+    # Mock os.path.isdir to force makedirs path, and os.makedirs to avoid filesystem side effects
+    with patch("os.path.isdir", return_value=False), patch("os.makedirs") as mock_makedirs:
         path = get_log_file_path(config, "server.log")
         assert path == "/tmp/data/logs/server.log"
         mock_makedirs.assert_called_once_with("/tmp/data/logs", exist_ok=True)
@@ -114,3 +118,102 @@ def test_log_viewer_controller_logging_separation():
         # Verify
         mock_get_logger_params.assert_called_with(log_file_name="logs_server.log")
         MockController.assert_called_with(logger=mock_logger)
+
+
+class TestJsonLogHandlerNotAttachedForInfrastructureLoggers:
+    """Verify that JsonLogHandler is NOT attached when log_file_name is explicit.
+
+    Infrastructure loggers (MCP server, log viewer) use explicit log_file_name
+    parameters. They must not write to webhooks_*.json to avoid polluting
+    webhook log queries with noise entries.
+    """
+
+    def test_no_json_handler_when_log_file_name_explicit(self) -> None:
+        """get_logger_with_params with explicit log_file_name must skip JsonLogHandler."""
+        with (
+            patch("webhook_server.utils.helpers.Config") as MockConfig,
+            patch("webhook_server.utils.helpers.get_logger") as mock_get_logger,
+        ):
+            mock_config_instance = MockConfig.return_value
+            mock_config_instance.data_dir = "/tmp/data"
+            mock_config_instance.get_value.side_effect = lambda value, return_on_none=None: return_on_none
+
+            mock_logger = MagicMock()
+            mock_logger.handlers = []
+            mock_get_logger.return_value = mock_logger
+
+            get_logger_with_params(log_file_name="mcp_server.log")
+
+            # JsonLogHandler must NOT be added
+            mock_logger.addHandler.assert_not_called()
+
+    def test_json_handler_attached_when_log_file_name_default(self) -> None:
+        """get_logger_with_params without log_file_name must attach JsonLogHandler."""
+        with (
+            patch("webhook_server.utils.helpers.Config") as MockConfig,
+            patch("webhook_server.utils.helpers.get_logger") as mock_get_logger,
+            patch("os.path.isdir", return_value=False),
+            patch("os.makedirs"),
+        ):
+            mock_config_instance = MockConfig.return_value
+            mock_config_instance.data_dir = "/tmp/data"
+            # Return a log file config so a file handler exists
+            mock_config_instance.get_value.side_effect = lambda value, return_on_none=None: (
+                "webhook_server.log" if value == "log-file" else return_on_none
+            )
+
+            mock_logger = MagicMock()
+            mock_logger.handlers = []  # No existing handlers
+            mock_get_logger.return_value = mock_logger
+
+            get_logger_with_params()  # No explicit log_file_name
+
+            # JsonLogHandler MUST be added
+            mock_logger.addHandler.assert_called_once()
+
+            added_handler = mock_logger.addHandler.call_args[0][0]
+            assert isinstance(added_handler, JsonLogHandler)
+
+
+class TestIsInfrastructureNoise:
+    """Verify _is_infrastructure_noise correctly identifies noise entries."""
+
+    @staticmethod
+    def _make_entry(logger_name: str, hook_id: str | None = None) -> LogEntry:
+        return LogEntry(
+            timestamp=datetime.datetime.now(tz=datetime.UTC),
+            level="INFO",
+            logger_name=logger_name,
+            message="test message",
+            hook_id=hook_id,
+        )
+
+    def test_mcp_logger_without_hook_id_is_noise(self) -> None:
+        entry = self._make_entry("mcp.server.streamable_http", hook_id=None)
+        assert LogViewerController._is_infrastructure_noise(entry) is True
+
+    def test_logs_server_logger_without_hook_id_is_noise(self) -> None:
+        entry = self._make_entry("logs_server.log", hook_id=None)
+        assert LogViewerController._is_infrastructure_noise(entry) is True
+
+    def test_mcp_server_log_without_hook_id_is_noise(self) -> None:
+        entry = self._make_entry("mcp_server.log", hook_id=None)
+        assert LogViewerController._is_infrastructure_noise(entry) is True
+
+    def test_log_parser_without_hook_id_is_noise(self) -> None:
+        entry = self._make_entry("log_parser", hook_id=None)
+        assert LogViewerController._is_infrastructure_noise(entry) is True
+
+    def test_infra_logger_with_hook_id_is_not_noise(self) -> None:
+        """Infrastructure logger entry WITH hook_id should be preserved."""
+        entry = self._make_entry("mcp.server.streamable_http", hook_id="abc-123")
+        assert LogViewerController._is_infrastructure_noise(entry) is False
+
+    def test_webhook_logger_without_hook_id_is_not_noise(self) -> None:
+        """Non-infrastructure logger without hook_id is kept (could be startup log)."""
+        entry = self._make_entry("GithubWebhook", hook_id=None)
+        assert LogViewerController._is_infrastructure_noise(entry) is False
+
+    def test_webhook_logger_with_hook_id_is_not_noise(self) -> None:
+        entry = self._make_entry("GithubWebhook", hook_id="abc-123")
+        assert LogViewerController._is_infrastructure_noise(entry) is False

webhook_server/utils/helpers.py

@@ -104,11 +104,16 @@ def get_logger_with_params(
     )
 
     # Attach JsonLogHandler for writing log records to the webhook JSONL file.
-    # Only attach when a log file path is configured (skip console-only loggers)
-    # and only once per logger instance to avoid duplicate handlers.
+    # Only attach when:
+    # - A log file path is configured (skip console-only loggers)
+    # - The logger is for the main webhook log (log_file_name not explicitly set)
+    #   Infrastructure loggers (mcp_server.log, logs_server.log) must NOT write
+    #   to webhooks_*.json because their entries lack webhook context (hook_id,
+    #   event_type, etc.) and pollute the webhook log with noise entries.
+    # - Only once per logger instance to avoid duplicate handlers.
     # Uses _config.data_dir/logs (same directory as StructuredLogWriter) instead
     # of deriving from the text log file path, which may differ for absolute paths.
-    if log_file_path_resolved:
+    if log_file_path_resolved and not log_file_name:
         log_dir = os.path.join(_config.data_dir, "logs")
         with _JSON_HANDLER_LOCK:
             if not any(isinstance(h, JsonLogHandler) and h.log_dir == Path(log_dir) for h in logger.handlers):

webhook_server/web/log_viewer.py

@@ -29,6 +29,17 @@ class LogViewerController:
     # 60 seconds provides a reasonable maximum window for log correlation
     _DEFAULT_STEP_DURATION_MS = 60000
 
+    # Logger names from infrastructure components (MCP server, log viewer itself) that
+    # should be excluded from webhook log queries. These loggers produce high-frequency
+    # noise entries without webhook context (hook_id, event_type are None) and would
+    # drown out actual webhook processing entries in unfiltered queries.
+    _INFRASTRUCTURE_LOGGERS: frozenset[str] = frozenset({
+        "mcp.server.streamable_http",
+        "logs_server.log",
+        "log_parser",
+        "mcp_server.log",
+    })
+
     # Workflow stage patterns for PR flow analysis
     # These patterns match log messages to identify workflow stages and can be updated
     # when log message formats change without modifying the analysis logic
@@ -288,6 +299,26 @@ def _entry_matches_filters(
 
         return True
 
+    @staticmethod
+    def _is_infrastructure_noise(entry: LogEntry) -> bool:
+        """Check if a log entry is infrastructure noise that should be excluded.
+
+        Infrastructure loggers (MCP server, log viewer) produce high-frequency
+        entries without webhook context. These are filtered out to prevent them
+        from drowning actual webhook processing entries in unfiltered queries.
+
+        Only excludes entries that have NO webhook context (hook_id is None),
+        preserving any infrastructure log that happens to correlate with a webhook.
+
+        Args:
+            entry: LogEntry to check
+
+        Returns:
+            True if the entry is infrastructure noise and should be excluded
+
+        """
+        return entry.logger_name in LogViewerController._INFRASTRUCTURE_LOGGERS and entry.hook_id is None
+
     async def export_logs(
         self,
         format_type: str,
@@ -1092,15 +1123,17 @@ def sort_key(f: Path) -> tuple[int, float]:
                     if log_file.suffix == ".json":
                         # JSONL files: one compact JSON object per line
                         # Process both "log_entry" and "webhook_summary" entries
+                        # Skip infrastructure logger entries that lack webhook context
                         async for line in f:
                             entry = self.log_parser.parse_json_log_entry(line)
-                            if entry:
+                            if entry and not LogViewerController._is_infrastructure_noise(entry):
                                 buffer.append(entry)
                     else:
                         # Text log files: parse line by line
+                        # Skip infrastructure logger entries that lack webhook context
                         async for line in f:
                             entry = self.log_parser.parse_log_entry(line)
-                            if entry:
+                            if entry and not LogViewerController._is_infrastructure_noise(entry):
                                 buffer.append(entry)
 
                 for entry in reversed(buffer):
@@ -1162,9 +1195,10 @@ async def _stream_text_log_entries(self, max_files: int = 25, max_entries: int =
                 buffer: deque[LogEntry] = deque(maxlen=remaining_capacity)
 
                 async with aiofiles.open(log_file, encoding="utf-8") as f:
+                    # Skip infrastructure logger entries that lack webhook context
                     async for line in f:
                         entry = self.log_parser.parse_log_entry(line)
-                        if entry:
+                        if entry and not LogViewerController._is_infrastructure_noise(entry):
                             buffer.append(entry)
 
                 for entry in reversed(buffer):