🚀 Installation

$ go get github.com/kataras/golog@latest

package mainimport ("github.com/kataras/golog")funcmain() {// Default Output is `os.Stdout`,// but you can change it:// golog.SetOutput(os.Stderr)// Time Format defaults to: "2006/01/02 15:04"// you can change it to something else or disable it with:// golog.SetTimeFormat("")// Level defaults to "info",// but you can change it:golog.SetLevel("debug")golog.Println("This is a raw message, no levels, no colors.")golog.Info("This is an info message, with colors (if the output is terminal)")golog.Warn("This is a warning message")golog.Error("This is an error message")golog.Debug("This is a debug message")golog.Fatal(`Fatal will exit no matter what,    but it will also print the log message if logger's Level is >=FatalLevel`)// Use any other supported logger through golog, e.g. the new "log/slog":// golog.Install(slog.Default())}

Log Levels

Helpers

// GetTextForLevel returns the level's (rich) text.fatalRichText:=golog.GetTextForLevel(golog.FatalLevel,true)// fatalRichText == "\x1b[41m[FTAL]\x1b[0m"

// ParseLevel returns a Level based on its string name.level:=golog.ParseLevel("debug")// level == golog.DebugLevel

Customization

funcinit() {// Levels contains a map of the log levels and their attributes.errorAttrs:=golog.Levels[golog.ErrorLevel]// Change a log level's text.customColorCode:=156errorAttrs.SetText("custom text",customColorCode)// Get (rich) text per log level.enableColors:=trueerrorRichText:=errorAttrs.Text(enableColors)}

golog.ErrorText("custom text",156)

Integration

opts:=badger.DefaultOptions("./data")opts.Logger=golog.Child("[badger]").DisableNewLine()db,err:=badger.Open(opts)// [...]

Level-based and standard Loggers

// Simulate an slog.Logger preparation.varmyLogger=slog.New(slog.NewJSONHandler(os.Stdout,&slog.HandlerOptions{Level:slog.LevelDebug,}))funcmain() {golog.SetLevel("error")golog.Install(myLogger)golog.Error("error message")}

// Simulate a log.Logger preparation.myLogger:=log.New(os.Stdout,"",0)golog.SetLevel("error")golog.Install(myLogger)golog.Error("error message")

// Simulate a logrus logger preparation.logrus.SetLevel(logrus.InfoLevel)logrus.SetFormatter(&logrus.JSONFormatter{})golog.Install(logrus.StandardLogger())golog.Debug(`this debug message will not be shown,    because the logrus level is InfoLevel`)golog.Error(`this error message will be visible as JSON,    because of logrus.JSONFormatter`)

Output Format

JSON

import"github.com/kataras/golog"funcmain() {golog.SetLevel("debug")golog.SetFormat("json","    ")// < --// main.go#29golog.Debugf("This is a %s with data (debug prints the stacktrace too)","message", golog.Fields{"username":"kataras",    })}

{"timestamp":1591423477,"level":"debug","message":"This is a message with data (debug prints the stacktrace too)","fields": {"username":"kataras"    },"stacktrace": [        {"function":"main.main","source":"C:/example/main.go:29"        }    ]}

Register custom Formatter

golog.RegisterFormatter(new(myFormatter))golog.SetFormat("myformat",options...)

// Formatter is responsible to print a log to the logger's writer.typeFormatterinterface {// The name of the formatter.String()string// Set any options and return a clone,// generic. See `Logger.SetFormat`.Options(opts...any)Formatter// Writes the "log" to "dest" logger.Format(dest io.Writer,log*Log)bool}

Custom Format usingHandler

typeHandlerfunc(value*Log) (handledbool)

import"encoding/json"funcjsonOutput(l*golog.Log)bool {enc:=json.NewEncoder(l.Logger.GetLevelOutput(l.Level.String()))enc.SetIndent("","    ")err:=enc.Encode(l)returnerr==nil}

import"github.com/kataras/golog"funcmain() {golog.SetLevel("debug")golog.Handle(jsonOutput)// main.go#29golog.Debugf("This is a %s with data (debug prints the stacktrace too)","message", golog.Fields{"username":"kataras",    })}

Examples

🔥 Benchmarks

👥 Contributing