Application logging: what to get right first

This is one of those topics that looks small until it costs you something. If you only fix one thing about application logging this quarter, make it the first item below.

The question is rarely whether something can be built, but what it costs to keep running afterwards. If two people in the business would answer this differently, that gap is the actual problem.

Start here

Logs are what you have when something breaks at 2am. That sounds obvious written down. It is still the thing most often skipped. Most teams find the first pass takes an afternoon and the maintenance takes minutes a month.

Then this

Structure them so they can be searched, not just read. The cost of getting this wrong is rarely visible on the day it happens. Doing this properly once is usually cheaper than doing it approximately three times.

Eventually

Never log passwords, tokens, or full card numbers. Where this goes wrong is almost never a lack of knowledge. Most teams find the first pass takes an afternoon and the maintenance takes minutes a month.

How to tell if yours is fine

Most development decisions are really maintenance decisions wearing a different hat. Three things worth confirming about application logging before you move on:

• Someone can say what the current setup is without going to look
• Never log passwords, tokens, or full card numbers — and you know whether that is true here
• There is a way to tell whether the last change to this helped

Worth checking on your own setup before it becomes someone else's problem to fix.