Python logging trap: The Log Line That Tells You Nothing

The alert fires at 2am. You ssh in, open the logs, and find this: ERROR myapp: connection pool exhausted One line. The error itself, and nothing else. You know what broke. You have no idea why. Was it a sudden traffic spike? A query that held a connection too long? A retry loop that ran away? The answer was in the DEBUG logs — but you turned those off six months ago because the noise was unbearable. Then there's the other version of this problem. A teammate pings you: "hey, can you send me t...