log

README

Log

Log is a logging interface for Go. That's it. Pass around the interface.

Rationale

Users want to standardise logging. Sometimes libraries log. We leave the underlying logging implementation to the user while allowing libraries to log by simply expecting something that satisfies the Logger interface. This leaves the user free to pre-configure structure, output, etc.

Interface

The interface is minimalistic on purpose

type Logger interface {
    Log(v ...interface{})
    Logf(format string, v ...interface{})
}

Example

Here's a logger that uses logrus and logs with predefined fields.

import (
	"github.com/go-log/log"
	"github.com/sirupsen/logrus"
)

type logrusLogger struct {
	*logrus.Entry
}

func (l *logrusLogger) Log(v ...interface{}) {
	l.Entry.Print(v...)
}

func (l *logrusLogger) Logf(format string, v ...interface{}) {
	l.Entry.Printf(format, v...)
}

func WithFields(f logrus.Fields) log.Logger {
	return &logrusLogger{logrus.WithFields(f)}	
}

The WithFields func returns a struct that satisfies the Logger interface.

Pre-configure a logger using WithFields and pass it as an option to a library.

import "github.com/lib/foo"

l := mylogger.WithFields(logrus.Fields{
	"library": "github.com/lib/foo",
})

f := foo.New(
	foo.WithLogger(l),
)

Documentation

Overview

Package log provides a log interface

Index

• func Log(v ...interface{})
• func Logf(format string, v ...interface{})
• type Logger

Functions

func Log

func Log(v ...interface{})

Log logs using the default logger

func Logf

func Logf(format string, v ...interface{})

Logf logs formatted using the default logger

Types

type Logger

type Logger interface {
	Log(v ...interface{})
	Logf(format string, v ...interface{})
}

Logger is a generic logging interface

var (
	// The global default logger
	DefaultLogger Logger = &noOpLogger{}
)