If you're a bit serious you can at least impose date, time to the millisecond, pointer to the source of the log line, level, and a message. Let s be crazy and even say the message could have a structure too, but I can feel the weight of effort on your shoulders and say you ve already saved yourself the embarassement a colleague of mine faced when he realized he couldnt give me millisecond timestamp, rendering a latency calculation in the past impossible.