log

It is a simple structured logging package for Go.

Features

• fast, easy to use, and pretty logging for development
• low to zero allocation
• JSON encoding format
• support multiple output and each output can have their own output level
• colored text for console handler (linux, mac, and windows are supported)
• context.Context integration

Handlers

• console
• gelf (graylog)
• memory (unit test)
• discard (benchmark)

Installation

Use go get

go get -u github.com/jasonsoft/log/v2

Get Started

package main

import (
	"errors"

	"github.com/jasonsoft/log"
	"github.com/jasonsoft/log/handlers/console"
)

func main() {
	// use console handler to log all level logs
	clog := console.New()
	log.AddHandler(clog, log.AllLevels...)

	// print message use DEBUG level
	logger.Debug("hello world")
}

Example

package main

import (
	"errors"

	"github.com/jasonsoft/log"
	"github.com/jasonsoft/log/handlers/console"
)

func main() {
	// use console handler to log all level logs
	clog := console.New()
	log.AddHandler(clog, log.AllLevels...)

	// optional: allow handlers to clear all buffer
	defer log.Flush()

	// use trace to get how long it takes
	defer log.Trace("time to run").Stop()

	logger := log.
		Str("app_id", "santa").
		Str("env", "dev")

	// print message use DEBUG level
	logger.Debug("hello world")

	// log information with custom fileds
	logger.Str("city", "keelung").Info("more info")

	// log error struct and print error message, stack trace will also be recorded
	err := errors.New("something bad happened")
	logger.Err(err).Error("oops...")
}

Output

Field Types

Standard Types

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

Benchmarks

Run on MacBook Pro 15-inch 2018 using go version go1.14.2 windows 10 OS

Using Uber's zap comparison benchmark:

Log a static string, without any context or printf-style templating:

Library	Time	Bytes Allocated	Objects Allocated
jasonsoft log	134 ns/op	0 B/op	0 allocs/op
zerolog	82 ns/op	0 B/op	0 allocs/op
⚡ zap	101 ns/op	0 B/op	0 allocs/op
standard library	339 ns/op	80 B/op	2 allocs/op
⚡ zap (sugared)	187 ns/op	80 B/op	2 allocs/op
go-kit	349 ns/op	640 B/op	11 allocs/op
logrus	3217 ns/op	1195 B/op	24 allocs/op
apex/log	1766 ns/op	344 B/op	6 allocs/op
log15	5157 ns/op	1195 B/op	24 allocs/op

Log a message with a logger that already has 10 fields of context:

Library	Time	Bytes Allocated	Objects Allocated
jasonsoft log	469 ns/op	0 B/op	0 allocs/op
zerolog	78 ns/op	0 B/op	0 allocs/op
⚡ zap	101 ns/op	0 B/op	0 allocs/op
⚡ zap (sugared)	168 ns/op	80 B/op	2 allocs/op
go-kit	5979 ns/op	3793 B/op	58 allocs/op
logrus	25518 ns/op	4186 B/op	68 allocs/op
apex/log	23583 ns/op	3406 B/op	55 allocs/op
log15	21155 ns/op	3446 B/op	72 allocs/op

Log a message and 10 fields:

Library	Time	Bytes Allocated	Objects Allocated
jasonsoft log	7439 ns/op	15086 B/op	42 allocs/op
zerolog	3906 ns/op	2614 B/op	32 allocs/op
⚡ zap	966 ns/op	772 B/op	5 allocs/op
⚡ zap (sugared)	1651 ns/op	1570 B/op	11 allocs/op
go-kit	5367 ns/op	3470 B/op	60 allocs/op
logrus	30444 ns/op	5772 B/op	80 allocs/op
apex/log	25479 ns/op	4363 B/op	67 allocs/op
log15	30315 ns/op	6859 B/op	77 allocs/op