1 简介

logrus的优点如下:

完全兼容标准的log库
内置了两种日志格式JSONFormater和TextFormatter
允许使用者通过Hook的方式将日志分发到任意地方
通过Filed机制进行结构化的日志记录

但是它用到了反射, 效率会相对低一点

提供的日志等级有:

logrus.Debug(“Useful debugging information.”)
logrus.Info(“Something noteworthy happened!”), 输出到stdout
logrus.Warn(“You should probably take a look at this.”)
logrus.Error(“Something failed but I’m not quitting.”), 输出到stderr, 还会继续执行
logrus.Panic(“I’m bailing.”) //log之后会panic(), 会退出所有协程
logrus.Fatal(“Bye.”) //log之后会调用os.Exit(1), 强制退出所有协程
2 使用示例
```go package main

import ( log “github.com/sirupsen/logrus” )

func main() { log.Info(“hello”)

log.WithFields(log.Fields{
    "animal": "walrus",
}).Info("a walrus appears")

}

运行结果如下:
```go
INFO[0000] hello                                        
INFO[0000] a walrus appears                              animal=walrus

3 设置log的参数

package main
import (
    log "github.com/sirupsen/logrus"
    "os"
)
func init() {
    log.SetFormatter(&log.JSONFormatter{})
    log.SetOutput(os.Stdout)
    log.SetLevel(log.InfoLevel)
}
func main() {
    log.Info("hello")
}

运行结果如下:

{"level":"info","msg":"hello","time":"2022-01-29T20:15:32+08:00"}

4 输出到文件

package main
import (
    log "github.com/sirupsen/logrus"
    "io"
    "os"
)
func init() {
    log.SetFormatter(&log.JSONFormatter{})
    writer1 := os.Stdout
    writer2, _ := os.OpenFile("log.txt", os.O_WRONLY|os.O_CREATE, 0755)
    // 同时输出到 控制台, 文件
    log.SetOutput(io.MultiWriter(writer1, writer2))
    // 设置日志只记录Info及以上
    log.SetLevel(log.InfoLevel)
}
func main() {
    log.Info("hello")
}

5 hook

hook的原理是，在logrus写入日志时拦截，修改logrus.Entry

package main
import (
    log "github.com/sirupsen/logrus"
    "io"
    "os"
)
type MyFieldHook struct {
}
func (this MyFieldHook) Fire(entry *log.Entry) error {
    entry.Data["tag"] = "ws"
    return nil
}
func (this MyFieldHook) Levels() []log.Level {
    return log.AllLevels
}
func init() {
    log.SetFormatter(&log.JSONFormatter{})
    writer1 := os.Stdout
    writer2, _ := os.OpenFile("log.txt", os.O_WRONLY|os.O_CREATE, 0755)
    log.SetOutput(io.MultiWriter(writer1, writer2))
    log.SetLevel(log.InfoLevel)
    hook := MyFieldHook{}
    log.AddHook(hook)
    log.SetReportCaller(true) // 输出文件名,行号,函数名
}
func main() {
    log.Info("hello")
}

运行结果如下:

{“file”:”/Users/ws/GolandProjects/awesomeProject/main.go:33”,”func”:”main.main”,”level”:”info”,”msg”:”hello”,”tag”:”ws”,”time”:”2022-01-29T20:35:54+08:00”}

6 日志文件切割

通过hook插件file-rotatelogs进行日志本地文件分割
日志轮转相关函数:

WithLinkName() 为最新的日志建立软连接
WithMaxAge() 设置文件清理前的最长保存时间
WithRotationTime() 设置日志分割的时间，隔多久分割一次
WithRotationCount() 设置文件清理前最多保存的个数

注: WithMaxAge 和 WithRotationCount二者只能设置一个

package main
import (
    "time"
    rotatelogs "github.com/lestrrat-go/file-rotatelogs"
    log "github.com/sirupsen/logrus"
)
func init() {
    path := "./log/go.log"
    writer, _ := rotatelogs.New(
        path+".%Y%m%d%H%M",                          // 正在记录的日志文件
        rotatelogs.WithLinkName(path),               // 正在记录的日志文件 对应的软链接(最好用绝对路径)
        rotatelogs.WithMaxAge(180*time.Second),      // 设置文件清理前的最长保存时间
        rotatelogs.WithRotationTime(60*time.Second), // 设置日志分割的时间，隔多久分割一次
    )
    log.SetOutput(writer)
}
func main() {
    for {
        log.Info("hello, world!")
        time.Sleep(2 * time.Second)
    }
}

7 记录到ElasticSearch

import (
    log "github.com/sirupsen/logrus"
    "github.com/olivere/elastic"
    "gopkg.in/sohlich/elogrus"
)
func initLog() {
    client, err := elastic.NewClient(elastic.SetURL("http://localhost:9200"))
    if err != nil {
        log.Panic(err)
    }
    hook, err := elogrus.NewElasticHook(client, "localhost", log.DebugLevel, "mylog")
    if err != nil {
        log.Panic(err)
    }
    log.AddHook(hook)
}

8 记录到Mongo

package main
import (
    log "github.com/sirupsen/logrus"
    "github.com/weekface/mgorus"
)
func main() {
    hook, err := mgorus.NewHooker("localhost:27017", "db", "collection")
    if err != nil {
        panic(err)
    }
    log.AddHook(hook)
    log.WithFields(logrus.Fields{
        "name": "zhangsan",
        "age":  28,
    }).Error("Hello world!")
}

有时会报错: Failed to write to log, invalid argument

Golang

日志高级处理-logrus