logger, _ := zap.NewProduction()
defer logger.Sync() // zap底層有緩沖。在任何情況下執(zhí)行 defer logger.Sync() 是一個(gè)很好的習(xí)慣
sugar := logger.Sugar()
sugar.Infow("failed to fetch URL",
 // 字段是松散類型，不是強(qiáng)類型
  "url", url,
  "attempt", 3,
  "backoff", time.Second,
)
sugar.Infof("Failed to fetch URL: %s", url)

logger, _ := zap.NewProduction()
defer logger.Sync()
logger.Info("failed to fetch URL",
  // 字段是強(qiáng)類型，不是松散類型
  zap.String("url", url),
  zap.Int("attempt", 3),
  zap.Duration("backoff", time.Second),
)

// https://github.com/uber-go/zap/blob/v1.24.0/logger.go#L127
func NewExample(options ...Option) *Logger {
	encoderCfg := zapcore.EncoderConfig{
        MessageKey:     "msg",  // 日志內(nèi)容key:val， 前面的key設(shè)為msg
		LevelKey:       "level", // 日志級(jí)別的key設(shè)為level
		NameKey:        "logger", // 日志名
		EncodeLevel:    zapcore.LowercaseLevelEncoder, //日志級(jí)別，默認(rèn)小寫
		EncodeTime:     zapcore.ISO8601TimeEncoder, // 日志時(shí)間
		EncodeDuration: zapcore.StringDurationEncoder,
	}
	core := zapcore.NewCore(zapcore.NewJSONEncoder(encoderCfg), os.Stdout, DebugLevel)
	return New(core).WithOptions(options...)
}

package main

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

func main() {
	logger := zap.NewExample()
	logger.Debug("this is debug message")
	logger.Info("this is info message")
	logger.Info("this is info message with fileds",
		zap.Int("age", 37), 
        zap.String("agender", "man"),
    )
	logger.Warn("this is warn message")
	logger.Error("this is error message")
}

package main

import (
	"time"

	"go.uber.org/zap"
)

func main() {
	logger, _ := zap.NewDevelopment()
	defer logger.Sync()

	logger.Info("failed to fetch url",
		// 強(qiáng)類型字段
		zap.String("url", "http://example.com"),
		zap.Int("attempt", 3),
		zap.Duration("duration", time.Second),
	)

	logger.With(
		// 強(qiáng)類型字段
		zap.String("url", "http://development.com"),
		zap.Int("attempt", 4),
		zap.Duration("duration", time.Second*5),
	).Info("[With] failed to fetch url")
}

package main

import (
	"time"

	"go.uber.org/zap"
)

func main() {
	logger, _ := zap.NewProduction()
	defer logger.Sync()

	url := "http://zap.uber.io"
	sugar := logger.Sugar()
	sugar.Infow("failed to fetch URL",
		"url", url,
		"attempt", 3,
		"time", time.Second,
	)

	sugar.Infof("Failed to fetch URL: %s", url)

	// 或更簡(jiǎn)潔 Sugar() 使用
	// sugar := zap.NewProduction().Sugar()
	// defer sugar.Sync()
}

package main

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

func main() {
	logger, _ := zap.NewProduction(zap.Fields(
		zap.String("log_name", "testlog"),
		zap.String("log_author", "prometheus"),
	))
	defer logger.Sync()

	logger.Info("test fields output")

	logger.Warn("warn info")
}

package main

import (
	"fmt"

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

func main() {
	logger := zap.NewExample(zap.Hooks(func(entry zapcore.Entry) error {
		fmt.Println("[zap.Hooks]test Hooks")
		return nil
	}))
	defer logger.Sync()

	logger.Info("test output")

	logger.Warn("warn info")
}

// 創(chuàng)建 logger
logger := zap.NewExample()
defer logger.Sync()

// 轉(zhuǎn)換 SugaredLogger
sugar := logger.Sugar()

// 轉(zhuǎn)換 logger
plain := sugar.Desugar()

// zap v1.24.0
type Config struct {
    // 動(dòng)態(tài)改變?nèi)罩炯?jí)別，在運(yùn)行時(shí)你可以安全改變?nèi)罩炯?jí)別
	Level AtomicLevel `json:"level" yaml:"level"`
    // 將日志記錄器設(shè)置為開發(fā)模式，在 WarnLevel 及以上級(jí)別日志會(huì)包含堆棧跟蹤信息
	Development bool `json:"development" yaml:"development"`
    // 在日志中停止調(diào)用函數(shù)所在文件名、行數(shù)
	DisableCaller bool `json:"disableCaller" yaml:"disableCaller"`
    // 完全禁止自動(dòng)堆棧跟蹤。默認(rèn)情況下，在 development 中，warnlevel及以上日志級(jí)別會(huì)自動(dòng)捕獲堆棧跟蹤信息
    // 在 production 中，ErrorLevel 及以上也會(huì)自動(dòng)捕獲堆棧信息
	DisableStacktrace bool `json:"disableStacktrace" yaml:"disableStacktrace"`
    // 設(shè)置采樣策略。沒(méi)有 SamplingConfing 將禁止采樣
	Sampling *SamplingConfig `json:"sampling" yaml:"sampling"`
    // 設(shè)置日志編碼。可以設(shè)置為 console 和 json。也可以通過(guò) RegisterEncoder 設(shè)置第三方編碼格式
	Encoding string `json:"encoding" yaml:"encoding"`
    // 為encoder編碼器設(shè)置選項(xiàng)。詳細(xì)設(shè)置信息在 zapcore.zapcore.EncoderConfig
	EncoderConfig zapcore.EncoderConfig `json:"encoderConfig" yaml:"encoderConfig"`
    // 日志輸出地址可以是一個(gè) URLs 地址或文件路徑，可以設(shè)置多個(gè)
	OutputPaths []string `json:"outputPaths" yaml:"outputPaths"`
    // 錯(cuò)誤日志輸出地址。默認(rèn)輸出標(biāo)準(zhǔn)錯(cuò)誤信息
	ErrorOutputPaths []string `json:"errorOutputPaths" yaml:"errorOutputPaths"`
    // 可以添加自定義的字段信息到 root logger 中。也就是每條日志都會(huì)攜帶這些字段信息，公共字段
	InitialFields map[string]interface{} `json:"initialFields" yaml:"initialFields"`
}

// zapcore@v1.24.0
type EncoderConfig struct {
    // 為log entry設(shè)置key。如果 key 為空，那么在日志中的這部分信息也會(huì)省略
	MessageKey     string `json:"messageKey" yaml:"messageKey"`//日志信息的健名，默認(rèn)為msg
	LevelKey       string `json:"levelKey" yaml:"levelKey"`//日志級(jí)別的健名，默認(rèn)為level
	TimeKey        string `json:"timeKey" yaml:"timeKey"`//記錄日志時(shí)間的健名，默認(rèn)為time
	NameKey        string `json:"nameKey" yaml:"nameKey"`
	CallerKey      string `json:"callerKey" yaml:"callerKey"`
	FunctionKey    string `json:"functionKey" yaml:"functionKey"`
	StacktraceKey  string `json:"stacktraceKey" yaml:"stacktraceKey"`
	SkipLineEnding bool   `json:"skipLineEnding" yaml:"skipLineEnding"`
	LineEnding     string `json:"lineEnding" yaml:"lineEnding"`
    // 日志編碼的一些設(shè)置項(xiàng)
	EncodeLevel    LevelEncoder    `json:"levelEncoder" yaml:"levelEncoder"`
	EncodeTime     TimeEncoder     `json:"timeEncoder" yaml:"timeEncoder"`
	EncodeDuration DurationEncoder `json:"durationEncoder" yaml:"durationEncoder"`
	EncodeCaller   CallerEncoder   `json:"callerEncoder" yaml:"callerEncoder"`
    // 與其它編碼器不同， 這個(gè)編碼器可選
	EncodeName NameEncoder `json:"nameEncoder" yaml:"nameEncoder"`
    // 配置 interface{} 類型編碼器。如果沒(méi)設(shè)置，將用 json.Encoder 進(jìn)行編碼
	NewReflectedEncoder func(io.Writer) ReflectedEncoder `json:"-" yaml:"-"`
    // 配置 console 中字段分隔符。默認(rèn)使用 tab 
	ConsoleSeparator string `json:"consoleSeparator" yaml:"consoleSeparator"`
}
type Entry struct {
	Level      Level
	Time       time.Time
	LoggerName string
	Message    string
	Caller     EntryCaller
	Stack      string
}

package main

import (
	"encoding/json"

	"go.uber.org/zap"
)

// https://pkg.go.dev/go.uber.org/zap@v1.24.0#hdr-Configuring_Zap
func main() {
	// 表示 zap.Config 的 json 原始編碼
	// outputPath: 設(shè)置日志輸出路徑，日志內(nèi)容輸出到標(biāo)準(zhǔn)輸出和文件 logs.log
	// errorOutputPaths：設(shè)置錯(cuò)誤日志輸出路徑
	rawJSON := []byte(`{
      "level": "debug",
      "encoding": "json",
      "outputPaths": ["stdout", "./logs.log"],
      "errorOutputPaths": ["stderr"],
      "initialFields": {"foo": "bar"},
      "encoderConfig": {
        "messageKey": "message-customer",
        "levelKey": "level",
        "levelEncoder": "lowercase"
      }
    }`)

	// 把 json 格式數(shù)據(jù)解析到 zap.Config struct
	var cfg zap.Config
	if err := json.Unmarshal(rawJSON, &cfg); err != nil {
		panic(err)
	}
	// cfg.Build() 為配置對(duì)象創(chuàng)建一個(gè) Logger
	// zap.Must() 封裝了 Logger，Must()函數(shù)如果返回值不是 nil，就會(huì)報(bào) panic。也就是檢查Build是否錯(cuò)誤
	logger := zap.Must(cfg.Build())
	defer logger.Sync()

	logger.Info("logger construction succeeded")
}

/*
Must() 函數(shù)
//  var logger = zap.Must(zap.NewProduction())
func Must(logger *Logger, err error) *Logger {
    if err != nil {
        panic(err)
    }

    return logger
}
*/

package main

import (
	"io"
	"os"

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

func main() {
	// 首先，定義不同級(jí)別日志處理邏輯
	highPriority := zap.LevelEnablerFunc(func(lvl zapcore.Level) bool {
		return lvl >= zapcore.ErrorLevel
	})
	lowPriority := zap.LevelEnablerFunc(func(lvl zapcore.Level) bool {
		return lvl < zapcore.ErrorLevel
	})

	// 假設(shè)有2個(gè)kafka 的 topic，一個(gè) debugging，一個(gè) errors

	// zapcore.AddSync 添加一個(gè)文件句柄。
	topicDebugging := zapcore.AddSync(io.Discard)
	topicErrors := zapcore.AddSync(io.Discard)

	// 如果他們對(duì)并發(fā)使用不安全，我們可以用 zapcore.Lock 添加一個(gè) mutex 互斥鎖。
	consoleDebugging := zapcore.Lock(os.Stdout)
	consoleErrors := zapcore.Lock(os.Stderr)

	// 設(shè)置 kafka 和 console 輸出配置
	kafkaEncoder := zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig())
	consoleEncoder := zapcore.NewConsoleEncoder(zap.NewDevelopmentEncoderConfig())

	// 把上面的設(shè)置加入到 zapcore.NewCore() 函數(shù)里，然后再把他們加入到 zapcore.NewTee() 函數(shù)里
	core := zapcore.NewTee(
		zapcore.NewCore(kafkaEncoder, topicErrors, highPriority),
		zapcore.NewCore(consoleEncoder, consoleErrors, highPriority),
		zapcore.NewCore(kafkaEncoder, topicDebugging, lowPriority),
		zapcore.NewCore(consoleEncoder, consoleDebugging, lowPriority),
	)

	// 最后調(diào)用 zap.New() 函數(shù)
	logger := zap.New(core)
	defer logger.Sync()
	logger.Info("constructed a logger")
}

package main

import (
	"os"

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

func main() {
	writetofile()
}

func writetofile() {
	// 設(shè)置一些配置參數(shù)
	config := zap.NewProductionEncoderConfig()
	config.EncodeTime = zapcore.ISO8601TimeEncoder
	fileEncoder := zapcore.NewJSONEncoder(config)
	defaultLogLevel := zapcore.DebugLevel // 設(shè)置 loglevel

	logFile, _ := os.OpenFile("./log-test-zap.json", os.O_WRONLY|os.O_CREATE|os.O_APPEND, 06666)
	// or os.Create()
	writer := zapcore.AddSync(logFile)

	logger := zap.New(
		zapcore.NewCore(fileEncoder, writer, defaultLogLevel),
		zap.AddCaller(),
		zap.AddStacktrace(zapcore.ErrorLevel),
	)
	defer logger.Sync()

	url := "http://www.test.com"
	logger.Info("write log to file",
		zap.String("url", url),
		zap.Int("attemp", 3),
	)
}

package main

import (
	"os"

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

func main() {
	writeToFileWithLogLevel()
}

func writeToFileWithLogLevel() {
	// 設(shè)置配置
	config := zap.NewProductionEncoderConfig()
	config.EncodeTime = zapcore.ISO8601TimeEncoder
	fileEncoder := zapcore.NewJSONEncoder(config)

	logFile, _ := os.OpenFile("./log-debug-zap.json", os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0666) //日志記錄debug信息

	errFile, _ := os.OpenFile("./log-err-zap.json", os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0666) //日志記錄error信息

	teecore := zapcore.NewTee(
		zapcore.NewCore(fileEncoder, zapcore.AddSync(logFile), zap.DebugLevel),
		zapcore.NewCore(fileEncoder, zapcore.AddSync(errFile), zap.ErrorLevel),
	)

	logger := zap.New(teecore, zap.AddCaller())
	defer logger.Sync()

	url := "http://www.diff-log-level.com"
	logger.Info("write log to file",
		zap.String("url", url),
		zap.Int("time", 3),
	)

	logger.With(
		zap.String("url", url),
		zap.String("name", "jimmmyr"),
	).Error("test error ")
}

package main

import (
	"fmt"

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

func main() {
	logger := zap.NewExample(zap.Hooks(func(entry zapcore.Entry) error {
		fmt.Println("[zap.Hooks]test Hooks")
		return nil
	}))
	defer logger.Sync()

	logger.Info("test output")

	logger.Warn("warn info")
}

package main

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

func main() {
	logger := zap.NewExample()
	defer logger.Sync()

	logger.Info("some message",
		zap.Namespace("shop"),
		zap.String("name", "LiLei"),
		zap.String("grade", "No2"),
	)

	logger.Error("some error message",
		zap.Namespace("shop"),
		zap.String("name", "LiLei"),
		zap.String("grade", "No3"),
	)
}

log.SetOutput(&lumberjack.Logger{
    Filename:   "/var/log/myapp/foo.log", // 文件位置
    MaxSize:    500,  // megabytes，M 為單位，達(dá)到這個(gè)設(shè)置數(shù)后就進(jìn)行日志切割
    MaxBackups: 3,    // 保留舊文件最大份數(shù)
    MaxAge:     28,   //days ， 舊文件最大保存天數(shù)
    Compress:   true, // disabled by default，是否壓縮日志歸檔，默認(rèn)不壓縮
})

package main

import (
	"fmt"

	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
	"gopkg.in/natefinch/lumberjack.v2"
)

func main() {
	lumberjacklogger := &lumberjack.Logger{
		Filename:   "./log-rotate-test.json",
		MaxSize:    1, // megabytes
		MaxBackups: 3,
		MaxAge:     28,   //days
		Compress:   true, // disabled by default
	}
	defer lumberjacklogger.Close()

	config := zap.NewProductionEncoderConfig()

	config.EncodeTime = zapcore.ISO8601TimeEncoder // 設(shè)置時(shí)間格式
	fileEncoder := zapcore.NewJSONEncoder(config)

	core := zapcore.NewCore(
		fileEncoder,                       //編碼設(shè)置
		zapcore.AddSync(lumberjacklogger), //輸出到文件
		zap.InfoLevel,                     //日志等級(jí)
	)

	logger := zap.New(core)
	defer logger.Sync()

    // 測(cè)試分割日志
	for i := 0; i < 8000; i++ {
		logger.With(
			zap.String("url", fmt.Sprintf("www.test%d.com", i)),
			zap.String("name", "jimmmyr"),
			zap.Int("age", 23),
			zap.String("agradege", "no111-000222"),
		).Info("test info ")
	}

}

// https://github.com/uber-go/zap/blob/v1.24.0/global.go

var (
	_globalMu sync.RWMutex
	_globalL  = NewNop()
	_globalS  = _globalL.Sugar()
)

func L() *Logger {
	_globalMu.RLock() // 加了讀鎖，所以并發(fā)使用是安全的
	l := _globalL
	_globalMu.RUnlock()
	return l
}

func S() *SugaredLogger {
	_globalMu.RLock() // 加了讀鎖，所以并發(fā)使用是安全的
	s := _globalS
	_globalMu.RUnlock()
	return s
}

func ReplaceGlobals(logger *Logger) func() {
	_globalMu.Lock()
	prev := _globalL
	_globalL = logger
	_globalS = logger.Sugar()
	_globalMu.Unlock()
	return func() { ReplaceGlobals(prev) } // 返回一個(gè)函數(shù)類型
}

// https://github.com/uber-go/zap/blob/v1.24.0/logger.go#L85

func NewNop() *Logger {
	return &Logger{
		core:        zapcore.NewNopCore(),
		errorOutput: zapcore.AddSync(io.Discard),
		addStack:    zapcore.FatalLevel + 1,
		clock:       zapcore.DefaultClock,
	}
}

package main

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

func main() {
	// 直接調(diào)用是不會(huì)記錄日志信息的，所以下面日志信息不會(huì)輸出
	zap.L().Info("no log info")
	zap.S().Info("no log info [sugared]")

	logger := zap.NewExample()
	defer logger.Sync()

	zap.ReplaceGlobals(logger) // 全局logger，zap.L() 和 zap.S() 需要調(diào)用 ReplaceGlobals 函數(shù)才會(huì)記錄日志信息
	zap.L().Info("log info")
	zap.S().Info("log info [sugared]")
}

package main

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

func main() {
	logger := zap.NewExample()
	defer logger.Sync()

	std := zap.NewStdLog(logger)
	std.Print("standard logger wrapper")
}

NewStdLogAt(l *Logger, level zapcore.Level) (*log.Logger, error)

package main

import (
	"log"

	"go.uber.org/zap"
)

func main() {
	logger := zap.NewExample()
	defer logger.Sync()

	undo := zap.RedirectStdLog(logger)
	log.Print("redirected standard library")
	undo()

	log.Print("this zap logger")
}

func RedirectStdLogAt(l *Logger, level zapcore.Level) (func(), error)

package main

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

func Hello() {
	Warn("hello", zap.String("h", "world"), zap.Int("c", 1))
}

func Warn(msg string, fields ...zap.Field) {
	zap.L().Warn(msg, fields...)
}

func main() {
	logger, _ := zap.NewProduction(zap.AddStacktrace(zapcore.WarnLevel))
	defer logger.Sync()

	zap.ReplaceGlobals(logger)

	Hello()
}

package main

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

func main() {
	logger, _ := zap.NewProduction(zap.AddCaller())
	defer logger.Sync()

	logger.Info("AddCaller：line No and filename")
}

package main

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

func main() {
	logger, _ := zap.NewProduction(zap.AddCaller(), zap.AddCallerSkip(1))
	defer logger.Sync()

	zap.ReplaceGlobals(logger)

	Hello()
}

func Hello() {
	Warn("hello", zap.String("h", "world"), zap.Int("c", 1))
}

func Warn(msg string, fields ...zap.Field) {
	zap.L().Warn(msg, fields...)
}

sugar := logger.Sugar()
sugar.Infow("failed to fetch URL",
            "url", url,
            "attempt", 3,
            "backoff", time.Second,
)

logger.Info("failed to fetch url",
		// 強(qiáng)類型字段
		zap.String("url", "http://example.com"),
		zap.Int("attempt", 3),
		zap.Duration("backoff", time.Second),
)

logger.Info("some message",
    zap.Namespace("shop"),
    zap.String("shopid", "s1234323"),
  )