玩转高性能日志库ZAP(3)

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引言

前几天有朋友问我，zap库是否支持同时打印到多个目标地址，比如1份打印到文件，1份到控制台，1份打印到kafka中。这是所有日志库都会支持的功能，zap当然也不例外。

示例

package main

import (
	"io/ioutil"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
	"gopkg.in/natefinch/lumberjack"
	"os"
)

func main(){
	// First, define our level-handling logic.
	// 仅打印Error级别以上的日志
	highPriority := zap.LevelEnablerFunc(func(lvl zapcore.Level) bool {
		return lvl >= zapcore.ErrorLevel
	})
	// 打印所有级别的日志
	lowPriority := zap.LevelEnablerFunc(func(lvl zapcore.Level) bool {
		return lvl >= zapcore.DebugLevel
	})

	hook := lumberjack.Logger{
		Filename:   "/tmp/abc.log",
		MaxSize:    1024, // megabytes
		MaxBackups: 3,
		MaxAge:     7,    //days
		Compress:   true, // disabled by default
	}


	topicErrors := zapcore.AddSync(ioutil.Discard)
	fileWriter := zapcore.AddSync(&hook)

	// High-priority output should also go to standard error, and low-priority
	// output should also go to standard out.
	consoleDebugging := zapcore.Lock(os.Stdout)

	// Optimize the Kafka output for machine consumption and the console output
	// for human operators.
	kafkaEncoder := zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig())
	consoleEncoder := zapcore.NewConsoleEncoder(zap.NewDevelopmentEncoderConfig())

	// Join the outputs, encoders, and level-handling functions into
	// zapcore.Cores, then tee the four cores together.
	core := zapcore.NewTee(
		// 打印在kafka topic中（伪造的case）
		zapcore.NewCore(kafkaEncoder, topicErrors, highPriority),
		// 打印在控制台
		zapcore.NewCore(consoleEncoder, consoleDebugging, lowPriority),
		// 打印在文件中
		zapcore.NewCore(consoleEncoder, fileWriter, highPriority),
	)

	// From a zapcore.Core, it's easy to construct a Logger.
	logger := zap.New(core)
	defer logger.Sync()
	logger.Info("constructed a info logger", zap.Int("test", 1))
	logger.Error("constructed a error logger", zap.Int("test", 2))
}

输出结果

文件中

2018-09-17T10:16:52.366+0800	ERROR	constructed a error logger	{"test": 2}

控制台

2018-09-17T10:16:52.365+0800	INFO	constructed a info logger	{"test": 1}
2018-09-17T10:16:52.366+0800	ERROR	constructed a error logger	{"test": 2}

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