Migrating a Production Service from Zap to slog: Notes from the Trenches
log/slog shipped in Go 1.21 in August 2023. It’s now been in the standard library for two years, and most production Go services I encounter are still on zap or zerolog. That’s not inertia — it’s a reasonable position. The third-party loggers are battle-tested and fast, and “the standard library now has one too” is not by itself a reason to migrate a working system. We migrated one of our services anyway. This post is about why, what the migration actually involved, and the honest accounting of what we gained and what we gave up. ...