Blazing fast, structured, leveled logging in Go

 Package zap provides fast, structured, leveled logging.
 .
 For applications that log in the hot path, reflection-based
 serialization and string formatting are prohibitively expensive,
 they're CPU-intensive and make many small allocations. Put
 differently, using json.Marshal and fmt.Fprintf to log tons of
 interface{} makes your application slow.
 .
 Zap takes a different approach. It includes a reflection-free,
 zero-allocation JSON encoder, and the base Logger strives to avoid
 serialization overhead and allocations wherever possible. By
 building the high-level SugaredLogger on that foundation, zap lets
 users choose when they need to count every allocation and when
 they'd prefer a more familiar, loosely typed API.