RipZap - The fastest structured, leveled JSON logger for Go zap. Dependency free.

The rz package provides a fast and simple logger dedicated to JSON output avoiding allocations and reflection..

Uber's zap and rs's zerolog libraries pioneered this approach.

ripzap is an update of zerolog taking this concept to the next level with a simpler to use and safer API and even better performance.

To keep the code base and the API simple, ripzap focuses on efficient structured logging only. Pretty logging on the console is made possible using the provided (but inefficient) Formatters.


package main

import (


func main() {

	env := os.Getenv("GO_ENV")
	hostname, _ := os.Hostname()

	// update global logger's context fields
		rz.String("hostname", hostname), rz.String("environment", env),

	if env == "production" {

	log.Info("info from logger", rz.String("hello", "world"))
	// {"level":"info","hostname":"","environment":"","hello":"world","timestamp":"2019-02-07T09:30:07Z","message":"info from logger"}



// Writer update logger's writer.
func Writer(writer io.Writer) LoggerOption {}
// Level update logger's level.
func Level(lvl LogLevel) LoggerOption {}
// Sampler update logger's sampler.
func Sampler(sampler LogSampler) LoggerOption {}
// AddHook appends hook to logger's hook
func AddHook(hook LogHook) LoggerOption {}
// Hooks replaces logger's hooks
func Hooks(hooks ...LogHook) LoggerOption {}
// With replaces logger's context fields
func With(fields func(*Event)) LoggerOption {}
// Stack enable/disable stack in error messages.
func Stack(enableStack bool) LoggerOption {}
// Timestamp enable/disable timestamp logging in error messages.
func Timestamp(enableTimestamp bool) LoggerOption {}
// Caller enable/disable caller field in message messages.
func Caller(enableCaller bool) LoggerOption {}
// Formatter update logger's formatter.
func Formatter(formatter LogFormatter) LoggerOption {}
// TimestampFieldName update logger's timestampFieldName.
func TimestampFieldName(timestampFieldName string) LoggerOption {}
// LevelFieldName update logger's levelFieldName.
func LevelFieldName(levelFieldName string) LoggerOption {}
// MessageFieldName update logger's messageFieldName.
func MessageFieldName(messageFieldName string) LoggerOption {}
// ErrorFieldName update logger's errorFieldName.
func ErrorFieldName(errorFieldName string) LoggerOption {}
// CallerFieldName update logger's callerFieldName.
func CallerFieldName(callerFieldName string) LoggerOption {}
// CallerSkipFrameCount update logger's callerSkipFrameCount.
func CallerSkipFrameCount(callerSkipFrameCount int) LoggerOption {}
// ErrorStackFieldName update logger's errorStackFieldName.
func ErrorStackFieldName(errorStackFieldName string) LoggerOption {}
// TimeFieldFormat update logger's timeFieldFormat.
func TimeFieldFormat(timeFieldFormat string) LoggerOption {}
// TimestampFunc update logger's timestampFunc.
func TimestampFunc(timestampFunc func() time.Time) LoggerOption {}


var (
	// DurationFieldUnit defines the unit for time.Duration type fields added
	// using the Duration method.
	DurationFieldUnit = time.Millisecond

	// DurationFieldInteger renders Duration fields as integer instead of float if
	// set to true.
	DurationFieldInteger = false

	// ErrorHandler is called whenever rz fails to write an event on its
	// output. If not set, an error is printed on the stderr. This handler must
	// be thread safe and non-blocking.
	ErrorHandler func(err error)

Field Types

Standard Types

  • String
  • Bool
  • Int, Int8, Int16, Int32, Int64
  • Uint, Uint8, Uint16, Uint32, Uint64
  • Float32, Float64

Advanced Fields

  • Err: Takes an error and render it as a string using the logger.errorFieldName field name.
  • Error: Adds a field with a error.
  • Timestamp: Insert a timestamp field with logger.timestampFieldName field name and formatted using logger.timeFieldFormat.
  • Time: Adds a field with the time formated with the logger.timeFieldFormat.
  • Duration: Adds a field with a time.Duration.
  • Dict: Adds a sub-key/value as a field of the event.
  • Interface: Uses reflection to marshal the type.