log

log

Here's a simple and extensible logging library for Go.

Features

• Simple API for basic logging
• Data field collecting and json marshaling
• Replaceable underlying implementation

Interface

Level

type Level uint

const (

• DebugLevel Level = iota
• InfoLevel
• WarningLevel
• ErrorLevel
• FatalLevel

)

Logger

type Logger interface {

• Debug(v ...any)
• Info(v ...any)
• Warn(v ...any)
• Error(v ...any)
• Fatal(v ...any) // will cause os.Exit(-1)
• Panic(v ...any) // will throw panic
• Print(v ...any) // use level from WithLevel
• Debugf(format string, v ...any)
• Infof(format string, v ...any)
• Warnf(format string, v ...any)
• Errorf(format string, v ...any)
• Fatalf(format string, v ...any) // will cause os.Exit(-1)
• Panicf(format string, v ...any) // will throw panic
• Printf(format string, v ...any) // use level from WithLevel
• With(v ...field.Field) Logger get cloned Logger with data field
• WithName(name string) Logger get cloned Logger with new name prefix
• WithLevel(level Level) Logger get cloned Logger with new level
• AddDepth(depth int) Logger get cloned Logger with increased caller skip count
• Standard() *log.Logger create a native logger, level comes from WithLevel
• Flush() error force sync buffer now

}

Function

• func Debug(m ...any)
• func Info(m ...any)
• func Warn(m ...any)
• func Error(m ...any)
• func Panic(m ...any)
• func Fatal(m ...any)
• func Debugf(format string, m ...any)
• func Infof(format string, m ...any)
• func Warnf(format string, m ...any)
• func Errorf(format string, m ...any)
• func Panicf(format string, m ...any)
• func Fatalf(format string, m ...any)
• func Printf(format string, m ...any)
• func With(v ...field.Field) Logger // same as Logger.With
• func WithName(name string) Logger // same as Logger.WithName
• func Use(l Logger) // replace global logger ( not thread safe )
• func Current() Logger // clone global logger

Usage

Basic example

package main

import (
  "encoding/json"
  "os"

  "github.com/go-haru/field"
  "github.com/go-haru/log"
)

package func main() {
  // replace logger ( optional, we have inherent implementation )
  log.With( /* your own implementation */)

  // normal text
  log.Info("starting up")

  // export logger
  var logger = log.Current()

  var configData struct{}
  var configFile = "./config.json"

  // add data field
  logger = logger.With(field.String("configFile", configFile))

  // mixed
  if h, err := os.Open(configFile); err != nil {
    logger.With(field.Error("cause", err)).Error("cant open file")
  } else if err = json.NewDecoder(h).Decode(&configData); err != nil {
    // fatal, will cause os.exit(-1)
    logger.With(field.Error("cause", err)).Fatal("cant parse file")
  }
}

Context injection example

as an example, we can make session logger for http request with tracing id:

package main

import (
  "context"
  "net"
  "net/http"

  "github.com/google/uuid"
  "github.com/go-haru/field"

  "github.com/go-haru/log"
)

func main() {
  (&http.Server{
    BaseContext: func(net.Listener) context.Context {
      // make logger
      var logger = log.With(field.Stringer("traceId", uuid.New()))
      // inject context
      return log.Context(context.Background(), logger)
    },
    Handler: http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
      // fetch logger
      var logger = log.C(request.Context())

      logger.Debugf("url: %v", request.URL.String())
    }),
  }).ListenAndServe()
}

Contributing

For convenience of PM, please commit all issue to Document Repo.

License

This project is licensed under the Apache License Version 2.0.

Use and contributions signify your agreement to honor the terms of this LICENSE.

Commercial support or licensing is conditionally available through organization email.