From 80f60e5468bf62db8c16416fd65fa84715659f14 Mon Sep 17 00:00:00 2001
From: Hongsheng Liu <liuhongsheng4@huawei.com>
Date: Sun, 4 Oct 2026 11:14:08 +0800
Subject: [PATCH] Timestamp the runner log lines
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Diagnosing the dogfood runner's 26-minute 'task listing failed' storm
(348 lines from a transient DB lock) was guesswork because runner.log
carried no timestamps at all. The runner process now configures
WARNING+ logging with asctime — runner.log is the only forensic trail
after a crash, and its lines must be placeable in time.
---
 src/nanodot/cli.py | 16 ++++++++++++++++
 tests/test_cli.py  | 17 +++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/src/nanodot/cli.py b/src/nanodot/cli.py
index 716d955..d14e4a2 100644
--- a/src/nanodot/cli.py
+++ b/src/nanodot/cli.py
@@ -12,6 +12,7 @@
 
 import argparse
 import getpass
+import logging
 import os
 import signal
 import subprocess
@@ -912,6 +913,7 @@ def unwind() -> None:
                         return 0
                     signal.signal(signal.SIGINT, _sigint)
                     signal.signal(signal.SIGTERM, _sigint)
+                    _configure_runner_logging()
                     print("nanodot runner started — Ctrl-C to stop", flush=True)
                     daemon.serve(stop)
                     print("nanodot runner stopped")
@@ -981,6 +983,20 @@ def _run_start(_: argparse.Namespace) -> int:
         return 1
 
 
+_RUNNER_LOG_FORMAT = "%(asctime)s %(levelname)s %(name)s %(message)s"
+
+
+def _configure_runner_logging() -> None:
+    """Timestamped WARNING+ logging for the runner process. runner.log
+    lines are the only forensic trail after a crash; without timestamps a
+    failure storm (e.g. a transient DB lock) cannot be placed in time.
+    Process-local: this is our own process, not a global library policy."""
+    logging.basicConfig(
+        level=logging.WARNING,
+        format=_RUNNER_LOG_FORMAT,
+    )
+
+
 def _runner_alive() -> bool:
     from nanodot.native.runner_control import running_pid
 
diff --git a/tests/test_cli.py b/tests/test_cli.py
index bbb7c76..792e0a3 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -391,3 +391,20 @@ def fake_input(prompt: str = "") -> str:
 
     assert main(["watch", "show", task.id]) == 0
     assert "flaky alerts:" in capsys.readouterr().out
+
+
+def test_runner_logging_is_timestamped() -> None:
+    """runner.log is the post-crash forensic trail; every line must carry
+    a timestamp (found missing while diagnosing the dogfood failure storm)."""
+    import logging
+    import re
+
+    from nanodot.cli import _RUNNER_LOG_FORMAT
+
+    rendered = logging.Formatter(_RUNNER_LOG_FORMAT).format(
+        logging.LogRecord(
+            "nanodot.native.daemon", logging.WARNING, __file__, 1,
+            "task listing failed; will retry next pass", None, None,
+        )
+    )
+    assert re.match(r"^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2},\d{3} ", rendered), rendered