lumberjack滚动日志

import "gopkg.in/natefinch/lumberjack.v2"

log.SetOutput(&lumberjack.Logger{
    Filename:   "/var/log/myapp/foo.log",
    MaxSize:    500, // megabytes
    MaxBackups: 3,
    MaxAge:     28, //days
    Compress:   true, // disabled by default
})

type Logger struct {
    // Filename is the file to write logs to.  Backup log files will be retained
    // in the same directory.  It uses <processname>-lumberjack.log in
    // os.TempDir() if empty.
    // Filename是日志将要写入的文件的名字。备份的日志文件将会保留在同级目录中。(后面的我没太懂什么意思，就不翻译了)
    Filename string `json:"filename" yaml:"filename"`

    // MaxSize is the maximum size in megabytes of the log file before it gets
    // rotated. It defaults to 100 megabytes.
    // MaxSize是日志文件轮转前的最大尺寸，单位是MB。它默认是100MB。
    MaxSize int `json:"maxsize" yaml:"maxsize"`

    // MaxAge is the maximum number of days to retain old log files based on the
    // timestamp encoded in their filename.  Note that a day is defined as 24
    // hours and may not exactly correspond to calendar days due to daylight
    // savings, leap seconds, etc. The default is not to remove old log files
    // based on age.
    // MaxAge是保留旧文件的最大日期，它基于编码在文件名中的时间戳来实现。注意，一天的定义是24小时，并且由于夏令时，闰秒等原因，可能与日历不对应默认是不移除旧的日志文件。
    MaxAge int `json:"maxage" yaml:"maxage"`

    // MaxBackups is the maximum number of old log files to retain.  The default
    // is to retain all old log files (though MaxAge may still cause them to get
    // deleted.)
    // MaxBackups是最大保存的日志文件数量。默认是保存所有的旧日志。(但MaxAge仍然会使旧文件被删除)
    MaxBackups int `json:"maxbackups" yaml:"maxbackups"`

    // LocalTime determines if the time used for formatting the timestamps in
    // backup files is the computer's local time.  The default is to use UTC
    // time.
    // LocalTime决定了备份日志时的时间戳的格式是否是本机的本地时间。默认是UTC时间。
    LocalTime bool `json:"localtime" yaml:"localtime"`

    // Compress determines if the rotated log files should be compressed
    // using gzip. The default is not to perform compression.
    // Compress决定了旧日志是否需要用gzip压缩。默认是不执行压缩。
    Compress bool `json:"compress" yaml:"compress"`
    // contains filtered or unexported fields
    // 过滤过的或未导出的字段
}

func (l *Logger) Close() error

func (l *Logger) Rotate() error

l := &lumberjack.Logger{}
log.SetOutput(l)
c := make(chan os.Signal, 1)
signal.Notify(c, syscall.SIGHUP)

go func() {
    for {
        <-c
        l.Rotate()
    }
}()

func (l *Logger) Write(p []byte) (n int, err error)

// main.go
package main

import (
	"github.com/sirupsen/logrus"
	"gray-ice.com/test/hooks"
)

func main() {
	// 新建logger
	logger := logrus.New()

	// 设置logger为JSON格式
	logger.SetFormatter(&logrus.JSONFormatter{})

	// 添加钩子
	logger.AddHook(&hooks.InfoHook{})

	// 循环打印
	for i := 0; i < 100*10000; i++ {
		logger.Info("Info output!")
		logger.Warn("Warn output!")
	}
}

// gray-ice.com/test/hooks/hooks.go
package hooks

import (
	"github.com/sirupsen/logrus"
	lj "gopkg.in/natefinch/lumberjack.v2"
)

var info_logger = &lj.Logger{
	Filename: "./log/info.log",
	MaxSize:  100,
	MaxAge:   1,
	Compress: false,
}

// 定义Info钩子
type InfoHook struct{}

// 实现Levels方法
func (h *InfoHook) Levels() []logrus.Level {
	return []logrus.Level{logrus.InfoLevel}
}

// 实现Fire方法
func (h *InfoHook) Fire(e *logrus.Entry) error {
	// 设置输出为Logger
	e.Logger.SetOutput(info_logger)
	return nil
}