Structured, pluggable logging for Go.
Logstash - transport and process your logs, events, or other data
Never use print for debugging again
Blazing fast, structured, leveled logging in Go.
A fast & simple, yet powerful & flexible logging framework for Mac and iOS
Like Prometheus, but for logs.
Fluentd: Unified Logging Layer (project under CNCF)
Fast C++ logging library.