Go 第三方库之 uber-go/zap

1.简介

zap 是 uber 开源的 Go 高性能日志库，支持不同的日志级别， 能够打印基本信息等，但不支持日志的分割，这里我们可以使用 lumberjack 也是 zap 官方推荐用于日志分割，结合这两个库我们就可以实现以下功能的日志机制：

• 能够将事件记录到文件中，而不是应用程序控制台；
• 日志切割能够根据文件大小、时间或间隔等来切割日志文件；
• 支持不同的日志级别，例如 DEBUG ， INFO ， WARN ， ERROR 等；
• 能够打印基本信息，如调用文件、函数名和行号，日志时间等；
   

2.下载安装使用

使用如下命令进行安装

go get -u go.uber.org/zap

或

go get github.com/uber-go/zap

注意：导入的时候得这样导入

import(
    "go.uber.org/zap"
)

3.zap looger使用

zap 提供了两种类型的日志记录器—和 Logger 和 Sugared Logger 。之间的区别是：

• 在每一微秒和每一次内存分配都很重要的上下文中，使用Logger。它甚至比SugaredLogger更快，内存分配次数也更少，但它只支持强类型的结构化日志记录。
• 在性能很好但不是很关键的上下文中，使用SugaredLogger。它比其他结构化日志记录包快 4-10 倍，并且支持结构化和 printf 风格的日志记录。

一般场景使用 Sugared Logger 就足够了

3.1 Logger

• 创建logger(zap提供了三种方式来创建logger)(zap.NewProduction()/zap.NewDevelopment或za)
• 通过创建的logger调用INFO,ERROR等进行日志输出

3.1.1NewExample

代码示例：

package main

import "go.uber.org/zap"

func main() {
	log := zap.NewExample()
	log.Debug("this is debug message")
	log.Info("this is info message")
	log.Info("this is info message with fileds",
		zap.Int("age", 24), zap.String("agender", "man"))
	log.Warn("this is warn message")
	log.Error("error message")
	log.Panic("panic message")
}

输出结果：

{"level":"debug","msg":"this is debug message"}
{"level":"info","msg":"this is info message"}
{"level":"info","msg":"this is info message with fileds","age":24,"agender":"man"}   
{"level":"warn","msg":"this is warn message"}
{"level":"error","msg":"error message"}
{"level":"panic","msg":"panic message"}
panic: panic message

 3.1.2 NewDevelopment

代码示例：

package main

import "go.uber.org/zap"

func main() {
	log, _ := zap.NewDevelopment()
	log.Debug("this is debug message")
	log.Info("this is info message")
	log.Info("this is info message with fileds",
		zap.Int("age", 24), zap.String("agender", "man"))
	log.Warn("this is warn message")
	log.Error("error message")
	log.Panic("panic message")
}

输出结果：

2021-12-31T14:23:54.919+0800    DEBUG   jwtGoTest/logT.go:7     this is debug message
2021-12-31T14:23:54.928+0800    INFO    jwtGoTest/logT.go:8     this is info message
2021-12-31T14:23:54.929+0800    INFO    jwtGoTest/logT.go:9     this is info message with fileds        {"age": 24, "agender": "man"}
2021-12-31T14:23:54.929+0800    WARN    jwtGoTest/logT.go:11    this is warn message
main.main
        E:/Test/Test/myGitTest/gittest/jwtGoTest/logT.go:11
runtime.main
        C:/Program Files/Go/src/runtime/proc.go:255
2021-12-31T14:23:54.929+0800    ERROR   jwtGoTest/logT.go:12    error message
main.main
        E:/Test/Test/myGitTest/gittest/jwtGoTest/logT.go:12
runtime.main
        C:/Program Files/Go/src/runtime/proc.go:255
2021-12-31T14:23:54.929+0800    PANIC   jwtGoTest/logT.go:13    panic message
main.main
        E:/Test/Test/myGitTest/gittest/jwtGoTest/logT.go:13
runtime.main
        C:/Program Files/Go/src/runtime/proc.go:255
panic: panic message

 3.1.3 NewProduction

代码示例：

package main

import "go.uber.org/zap"

func main() {
	log, _ := zap.NewProduction()
	log.Debug("this is debug message")
	log.Info("this is info message")
	log.Info("this is info message with fileds",
		zap.Int("age", 24), zap.String("agender", "man"))
	log.Warn("this is warn message")
	log.Error("error message")
	log.Panic("panic message")
}

输出结果：

{"level":"info","ts":1640931968.8371582,"caller":"jwtGoTest/logT.go:8","msg":"this is info message"}
{"level":"info","ts":1640931968.8371582,"caller":"jwtGoTest/logT.go:9","msg":"this is info message with fileds","age":24,"agender":"man"}
{"level":"warn","ts":1640931968.8377013,"caller":"jwtGoTest/logT.go:11","msg":"this is warn message"}
{"level":"error","ts":1640931968.8377013,"caller":"jwtGoTest/logT.go:12","msg":"error message","stacktrace":"main.main\n\tE:/Test/Test/myGitTest/gittest/jwtGoTest/logT.go:12\nruntime.main\n\tC:/Program Files/Go/src/runtime/proc.go:255"}
{"level":"panic","ts":1640931968.8377013,"caller":"jwtGoTest/logT.go:13","msg":"panic message","stacktrace":"main.main\n\tE:/Test/Test/myGitTest/gittest/jwtGoTest/logT.go:13\nruntime.main\n\tC:/Program Files/Go/src/runtime/proc.go:255"}
panic: panic message

 总结

• Example和Production都是以json形式输出，Develpoment使用行的形式输出
• Develpoment打印包/文件/行，以大写形式打印级别名称，以毫秒为单位打印时间戳、
• 调试级别不记录，始终将调用者添加到文件中，以时间戳格式打印日期，以小写形式打印级别名称

3.2 Sugared Logger

使用：

通过主logger的Sugar()方法来获取一个SugaredLogger

示例：

package main

import "go.uber.org/zap"

func main() {
	log, _ := zap.NewDevelopment()
	sugarLog := log.Sugar()
	sugarLog.Debugf("debug message age is %d, agender is %s", 19, "man")
	sugarLog.Info("Info() uses sprint")
	sugarLog.Infof("Infof() uses %s", "sprintf")
	sugarLog.Infow("Infow() allows tags", "name", "Legolas", "type", 1)
}

输出结果：

2021-12-31T14:47:43.705+0800    DEBUG   jwtGoTest/logT.go:8     debug message age is 19, agender is man
2021-12-31T14:47:43.714+0800    INFO    jwtGoTest/logT.go:9     Info() uses sprint
2021-12-31T14:47:43.714+0800    INFO    jwtGoTest/logT.go:10    Infof() uses sprintf
2021-12-31T14:47:43.714+0800    INFO    jwtGoTest/logT.go:11    Infow() allows tags     {"name": "Legolas", "type": 1}

 如果需要，可以调用 Desugar() 方法从 sugar logger 切回到标准记录器

4.将日志写入文件

要将日志写入文件，就必须用zap.New()方法来传递配置，而不能像前面那样用预置方法创建logger

func zap.New(core zapcore.Core, options ...zap.Option) *zap.Logger

zapcore需要三个配置----Encoder,WriteSyncer,LogLevel

Encoder：编码器(如何写入日志)

encoder := zapcore.NewConsoleEncoder(zap.NewDevelopmentEncoderConfig())

WriterSyncer：指定日志将写到哪去。使用zapcore.Addsync()函数将打开的文件句柄传进去

file, _ := os.Create("./test.log") 
writeSyncer := zapcore.AddSync(file)

 或输出到控制台

consoleSyncer := zapcore.AddSync(os.Stdout)

LogLevel:哪种级别的日志将被写入

代码示例：

package main

import (
	"os"

	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
)

func main() {
	encoder := zapcore.NewConsoleEncoder(zap.NewDevelopmentEncoderConfig())
	file, _ := os.Create("./test.log")
	writeSync := zapcore.AddSync(file)
	core := zapcore.NewCore(encoder, writeSync, zap.DebugLevel)
	sugarLogger := zap.New(core, zap.AddCaller()).Sugar()
	sugarLogger.Info("this is info message")
	sugarLogger.Infof("this is %s, %d", "aaa", 1234)
	sugarLogger.Error("this is error message")
	sugarLogger.Info("this is info message")
}

 输出日志文件：

2021-12-31T15:05:14.810+0800	INFO	jwtGoTest/logT.go:16	this is info message
2021-12-31T15:05:14.818+0800	INFO	jwtGoTest/logT.go:17	this is aaa, 1234
2021-12-31T15:05:14.818+0800	ERROR	jwtGoTest/logT.go:18	this is error message
2021-12-31T15:05:14.818+0800	INFO	jwtGoTest/logT.go:19	this is info message

5.使用lumberjack进行日志切割归档

zap本身不支持切割归档日志文件，为了添加日志切割归档功能，使用lumberjack库来完成

5.1 安装lumberjak 

go get github.com/natefinch/lumberjack

5.2 使用

要在zap中加入lumberjack支持，需要修改wrierSync代码

lumberJackLogger := &lumberjack.Logger{
		Filename:   "./lumber.log",
		MaxSize:    10,
		MaxBackups: 5,
		MaxAge:     30,
		Compress:   false,
	}
writerSyncer := zapcore.AddSync(lumberJackLogger)

lumberjack logger属性：

• Filename：日志文件的位置
• Maxsize：在进行切割之前，日志文件的最大大小
• MaxBackups：保留旧文件的最大个数
• MaxAges：保留旧文件的最大天数
• Compress：是否压缩/归档旧文件

代码示例：

package main

import (
	"os"

	"github.com/natefinch/lumberjack"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
)

func main() {
	encoder := zapcore.NewConsoleEncoder(zap.NewDevelopmentEncoderConfig())
	// file, _ := os.Create("./test.log")
	lumberJackLogger := &lumberjack.Logger{
		Filename:   "./lumber.log",
		MaxSize:    10,
		MaxBackups: 5,
		MaxAge:     30,
		Compress:   false,
	}
	writerSyncer := zapcore.AddSync(lumberJackLogger)
	consoleSyncer := zapcore.AddSync(os.Stdout)
	core := zapcore.NewTee(
		zapcore.NewCore(encoder, writerSyncer, zapcore.DebugLevel),
		zapcore.NewCore(encoder, consoleSyncer, zapcore.DebugLevel),
	)
	log := zap.New(core, zap.AddCaller())
	sugarLogger := log.Sugar()
	sugarLogger.Info("this is info message")
	sugarLogger.Infof("this is %s, %d", "aaa", 1234)
	sugarLogger.Error("this is error message")
	sugarLogger.Info("this is info message")
}

日志文件输出结果：

2021-12-31T15:12:29.885+0800	INFO	gittest/logTest.go:29	this is info message
2021-12-31T15:12:29.899+0800	INFO	gittest/logTest.go:30	this is aaa, 1234
2021-12-31T15:12:29.899+0800	ERROR	gittest/logTest.go:31	this is error message
2021-12-31T15:12:29.899+0800	INFO	gittest/logTest.go:32	this is info message