Go 语言之自定义 zap 日志
zap 日志：https://github.com/uber-go/zap
一、日志写入文件
zap.NewProduction、zap.NewDevelopment是预设配置好的。zap.New可自定义配置
zap.New源码
这是构造Logger最灵活的方式，但也是最冗长的方式。
对于典型的用例，高度固执己见的预设(NewProduction、NewDevelopment和NewExample)或Config结构体更方便。
// New constructs a new Logger from the provided zapcore.Core and Options. If
// the passed zapcore.Core is nil, it falls back to using a no-op
// implementation.
//
// This is the most flexible way to construct a Logger, but also the most
// verbose. For typical use cases, the highly-opinionated presets
// (NewProduction, NewDevelopment, and NewExample) or the Config struct are
// more convenient.
//
// For sample code, see the package-level AdvancedConfiguration example.
func New(core zapcore.Core, options ...Option) *Logger {
if core == nil {
return NewNop()
}
log := &Logger{
core: core,
errorOutput: zapcore.Lock(os.Stderr),
addStack: zapcore.FatalLevel + 1,
clock: zapcore.DefaultClock,
}
return log.WithOptions(options...)
}
zapcore.Core 源码
// Core is a minimal, fast logger interface. It's designed for library authors
// to wrap in a more user-friendly API.
type Core interface {
LevelEnabler
// With adds structured context to the Core.
With([]Field) Core
// Check determines whether the supplied Entry should be logged (using the
// embedded LevelEnabler and possibly some extra logic). If the entry
// should be logged, the Core adds itself to the CheckedEntry and returns
// the result.
//
// Callers must use Check before calling Write.
Check(Entry, *CheckedEntry) *CheckedEntry
// Write serializes the Entry and any Fields supplied at the log site and
// writes them to their destination.
//
// If called, Write should always log the Entry and Fields; it should not
// replicate the logic of Check.
Write(Entry, []Field) error
// Sync flushes buffered logs (if any).
Sync() error
}
zapcore.AddSync(file) 源码解析
func AddSync(w io.Writer) WriteSyncer {
switch w := w.(type) {
case WriteSyncer:
return w
default:
return writerWrapper{w}
}
}
type writerWrapper struct {
io.Writer
}
func (w writerWrapper) Sync() error {
return nil
}
type WriteSyncer interface {
io.Writer
Sync() error
}
日志级别
// A Level is a logging priority. Higher levels are more important.
type Level int8
const (
// DebugLevel logs are typically voluminous, and are usually disabled in
// production.
DebugLevel Level = iota - 1
// InfoLevel is the default logging priority.
InfoLevel
// WarnLevel logs are more important than Info, but don't need individual
// human review.
WarnLevel
// ErrorLevel logs are high-priority. If an application is running smoothly,
// it shouldn't generate any error-level logs.
ErrorLevel
// DPanicLevel logs are particularly important errors. In development the
// logger panics after writing the message.
DPanicLevel
// PanicLevel logs a message, then panics.
PanicLevel
// FatalLevel logs a message, then calls os.Exit(1).
FatalLevel
_minLevel = DebugLevel
_maxLevel = FatalLevel
// InvalidLevel is an invalid value for Level.
//
// Core implementations may panic if they see messages of this level.
InvalidLevel = _maxLevel + 1
)
实操
package main
import (
"go.uber.org/zap"
"go.uber.org/zap/zapcore"
"net/http"
"os"
)
// 定义一个全局 logger 实例
// Logger提供快速、分级、结构化的日志记录。所有方法对于并发使用都是安全的。
// Logger是为每一微秒和每一个分配都很重要的上下文设计的，
// 因此它的API有意倾向于性能和类型安全，而不是简便性。
// 对于大多数应用程序，SugaredLogger在性能和人体工程学之间取得了更好的平衡。
var logger *zap.Logger
// SugaredLogger将基本的Logger功能封装在一个较慢但不那么冗长的API中。任何Logger都可以通过其Sugar方法转换为sugardlogger。
//与Logger不同，SugaredLogger并不坚持结构化日志记录。对于每个日志级别，它公开了四个方法:
// - methods named after the log level for log.Print-style logging
// - methods ending in "w" for loosely-typed structured logging
// - methods ending in "f" for log.Printf-style logging
// - methods ending in "ln" for log.Println-style logging
// For example, the methods for InfoLevel are:
//
// Info(...any) Print-style logging
// Infow(...any) Structured logging (read as "info with")
// Infof(string, ...any) Printf-style logging
// Infoln(...any) Println-style logging
var sugarLogger *zap.SugaredLogger
func main() {
// 初始化
InitLogger()
// Sync调用底层Core的Sync方法，刷新所有缓冲的日志条目。应用程序在退出之前应该注意调用Sync。
// 在程序退出之前，把缓冲区里的日志刷到磁盘上
defer logger.Sync()
simpleHttpGet("www.baidu.com")
simpleHttpGet("http://www.baidu.com")
}
func InitLogger() {
writeSyncer := getLogWriter()
encoder := getEncoder()
// NewCore创建一个向WriteSyncer写入日志的Core。
// A WriteSyncer is an io.Writer that can also flush any buffered data. Note
// that *os.File (and thus, os.Stderr and os.Stdout) implement WriteSyncer.
// LevelEnabler决定在记录消息时是否启用给定的日志级别。
// Each concrete Level value implements a static LevelEnabler which returns
// true for itself and all higher logging levels. For example WarnLevel.Enabled()
// will return true for WarnLevel, ErrorLevel, DPanicLevel, PanicLevel, and
// FatalLevel, but return false for InfoLevel and DebugLevel.
core := zapcore.NewCore(encoder, writeSyncer, zapcore.DebugLevel)
// New constructs a new Logger from the provided zapcore.Core and Options. If
// the passed zapcore.Core is nil, it falls back to using a no-op
// implementation.
logger = zap.New(core)
// Sugar封装了Logger，以提供更符合人体工程学的API，但速度略慢。糖化一个Logger的成本非常低，
// 因此一个应用程序同时使用Loggers和SugaredLoggers是合理的，在性能敏感代码的边界上在它们之间进行转换。
sugarLogger = logger.Sugar()
}
func getEncoder() zapcore.Encoder {
// NewJSONEncoder创建了一个快速、低分配的JSON编码器。编码器适当地转义所有字段键和值。
// NewProductionEncoderConfig returns an opinionated EncoderConfig for
// production environments.
return zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig())
}
func getLogWriter() zapcore.WriteSyncer {
// Create创建或截断指定文件。如果文件已经存在，它将被截断。如果该文件不存在，则以模式0666(在umask之前)创建。
// 如果成功，返回的File上的方法可以用于IO;关联的文件描述符模式为O_RDWR。如果有一个错误，它的类型将是PathError。
file, _ := os.Create("./test.log")
// AddSync converts an io.Writer to a WriteSyncer. It attempts to be
// intelligent: if the concrete type of the io.Writer implements WriteSyncer,
// we'll use the existing Sync method. If it doesn't, we'll add a no-op Sync.
return zapcore.AddSync(file)
}
func simpleHttpGet(url string) {
// Get向指定的URL发出Get命令。如果响应是以下重定向代码之一，则Get跟随重定向，最多可重定向10个:
// 301 (Moved Permanently)
// 302 (Found)
// 303 (See Other)
// 307 (Temporary Redirect)
// 308 (Permanent Redirect)
// Get is a wrapper around DefaultClient.Get.
// 使用NewRequest和DefaultClient.Do来发出带有自定义头的请求。
resp, err := http.Get(url)
if err != nil {
// Error在ErrorLevel记录消息。该消息包括在日志站点传递的任何字段，以及日志记录器上积累的任何字段。
//logger.Error(
// 错误使用fmt。以Sprint方式构造和记录消息。
sugarLogger.Error(
"Error fetching url..",
zap.String("url", url), // 字符串用给定的键和值构造一个字段。
zap.Error(err)) // // Error is shorthand for the common idiom NamedError("error", err).
} else {
// Info以infollevel记录消息。该消息包括在日志站点传递的任何字段，以及日志记录器上积累的任何字段。
//logger.Info("Success..",
// Info使用fmt。以Sprint方式构造和记录消息。
sugarLogger.Info("Success..",
zap.String("statusCode", resp.Status),
zap.String("url", url))
resp.Body.Close()
}
}
运行
Code/go/zap_demo via
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