Metrics

I was working on a logger that writes metrics every time a warning or an error is logged. I tried to provide additional metric tags depending on the log annotations. And it didn't work. I was adding an annotation and I could see its value somewhere deep in the stack trace but the annotations value was empty.

Turned out that ZIO has two log annotation mechanisms that work in parallel.

This post is a confession about multiple overlapping mistakes we made when trying to measure API request times. These errors went unnoticed for months because wrong statistics still look realistic. Hopefully, this post will help you avoid such fails.