Go 语言之在 gin 框架中使用 zap 日志库

gin 框架默认使用的是自带的日志

gin.Default()
func Default() *Engine {
  debugPrintWARNINGDefault()
  engine := New()
  engine.Use(Logger(), Recovery())
  return engine
}
​
// Logger instances a Logger middleware that will write the logs to gin.DefaultWriter.
// By default, gin.DefaultWriter = os.Stdout.
func Logger() HandlerFunc {
  return LoggerWithConfig(LoggerConfig{})
}
​
// Recovery returns a middleware that recovers from any panics and writes a 500 if there was one.
func Recovery() HandlerFunc {
  return RecoveryWithWriter(DefaultErrorWriter)
}
​
// RecoveryWithWriter returns a middleware for a given writer that recovers from any panics and writes a 500 if there was one.
func RecoveryWithWriter(out io.Writer, recovery ...RecoveryFunc) HandlerFunc {
  if len(recovery) > 0 {
    return CustomRecoveryWithWriter(out, recovery[0])
  }
  return CustomRecoveryWithWriter(out, defaultHandleRecovery)
}
​
// CustomRecoveryWithWriter returns a middleware for a given writer that recovers from any panics and calls the provided handle func to handle it.
func CustomRecoveryWithWriter(out io.Writer, handle RecoveryFunc) HandlerFunc {
  var logger *log.Logger
  if out != nil {
    logger = log.New(out, "\n\n\x1b[31m", log.LstdFlags)
  }
  return func(c *Context) {
    defer func() {
      if err := recover(); err != nil {
        // Check for a broken connection, as it is not really a
        // condition that warrants a panic stack trace.
        var brokenPipe bool
        if ne, ok := err.(*net.OpError); ok {
          var se *os.SyscallError
          if errors.As(ne, &se) {
            seStr := strings.ToLower(se.Error())
            if strings.Contains(seStr, "broken pipe") ||
              strings.Contains(seStr, "connection reset by peer") {
              brokenPipe = true
            }
          }
        }
        if logger != nil {
          stack := stack(3)
          httpRequest, _ := httputil.DumpRequest(c.Request, false)
          headers := strings.Split(string(httpRequest), "\r\n")
          for idx, header := range headers {
            current := strings.Split(header, ":")
            if current[0] == "Authorization" {
              headers[idx] = current[0] + ": *"
            }
          }
          headersToStr := strings.Join(headers, "\r\n")
          if brokenPipe {
            logger.Printf("%s\n%s%s", err, headersToStr, reset)
          } else if IsDebugging() {
            logger.Printf("[Recovery] %s panic recovered:\n%s\n%s\n%s%s",
              timeFormat(time.Now()), headersToStr, err, stack, reset)
          } else {
            logger.Printf("[Recovery] %s panic recovered:\n%s\n%s%s",
              timeFormat(time.Now()), err, stack, reset)
          }
        }
        if brokenPipe {
          // If the connection is dead, we can't write a status to it.
          c.Error(err.(error)) //nolint: errcheck
          c.Abort()
        } else {
          handle(c, err)
        }
      }
    }()
    c.Next()
  }
}
​

自定义 Logger(), Recovery()

实操

package main
​
import (
  "github.com/gin-gonic/gin"
  "go.uber.org/zap"
  "go.uber.org/zap/zapcore"
  "gopkg.in/natefinch/lumberjack.v2"
  "net"
  "net/http"
  "net/http/httputil"
  "os"
  "runtime/debug"
  "strings"
  "time"
)
​
// 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")
//
//  for i := 0; i < 10000; i++ {
//    logger.Info("test lumberjack for log rotate....")
//  }
//}
​
func main() {
  InitLogger()
  //r := gin.Default()
​
  r := gin.New()
  r.Use(GinLogger(logger), GinRecovery(logger, true))
  r.GET("/hello", func(c *gin.Context) {
    c.String(http.StatusOK, "hello xiaoqiao!")
  })
  r.Run()
}
​
// GinLogger
func GinLogger(logger *zap.Logger) gin.HandlerFunc {
  return func(c *gin.Context) {
    start := time.Now()
    path := c.Request.URL.Path
    query := c.Request.URL.RawQuery
    c.Next() // 执行后续中间件
​
    // Since returns the time elapsed since t.
    // It is shorthand for time.Now().Sub(t).
    cost := time.Since(start)
    logger.Info(path,
      zap.Int("status", c.Writer.Status()),
      zap.String("method", c.Request.Method),
      zap.String("path", path),
      zap.String("query", query),
      zap.String("ip", c.ClientIP()),
      zap.String("user-agent", c.Request.UserAgent()),
      zap.String("errors", c.Errors.ByType(gin.ErrorTypePrivate).String()),
      zap.Duration("cost", cost), // 运行时间
    )
  }
}
​
// GinRecovery
func GinRecovery(logger *zap.Logger, stack bool) gin.HandlerFunc {
  return func(c *gin.Context) {
    defer func() {
      if err := recover(); err != nil {
        // Check for a broken connection, as it is not really a
        // condition that warrants a panic stack trace.
        var brokenPipe bool
        if ne, ok := err.(*net.OpError); ok {
          if se, ok := ne.Err.(*os.SyscallError); ok {
            if strings.Contains(strings.ToLower(se.Error()), "broken pipe") || strings.Contains(strings.ToLower(se.Error()), "connection reset by peer") {
              brokenPipe = true
            }
          }
        }
​
        httpRequest, _ := httputil.DumpRequest(c.Request, false)
        if brokenPipe {
          logger.Error(c.Request.URL.Path,
            zap.Any("error", err),
            zap.String("request", string(httpRequest)),
          )
          // If the connection is dead, we can't write a status to it.
          c.Error(err.(error)) // nolint: errcheck
          c.Abort()
          return
        }
​
        if stack {
          logger.Error("[Recovery from panic]",
            zap.Any("error", err),
            zap.String("request", string(httpRequest)),
            zap.String("stack", string(debug.Stack())),
          )
        } else {
          logger.Error("[Recovery from panic]",
            zap.Any("error", err),
            zap.String("request", string(httpRequest)),
          )
        }
        c.AbortWithStatus(http.StatusInternalServerError)
      }
    }()
    c.Next()
  }
}
​
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.
​
  // AddCaller configures the Logger to annotate each message with the filename,
  // line number, and function name of zap's caller. See also WithCaller.
  logger = zap.New(core, zap.AddCaller())
  // 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())
​
  // NewConsoleEncoder创建一个编码器,其输出是为人类而不是机器设计的。
  // 它以纯文本格式序列化核心日志条目数据(消息、级别、时间戳等),并将结构化上下文保留为JSON。
  encoderConfig := zapcore.EncoderConfig{
    TimeKey:        "ts",
    LevelKey:       "level",
    NameKey:        "logger",
    CallerKey:      "caller",
    FunctionKey:    zapcore.OmitKey,
    MessageKey:     "msg",
    StacktraceKey:  "stacktrace",
    LineEnding:     zapcore.DefaultLineEnding,
    EncodeLevel:    zapcore.LowercaseLevelEncoder,
    EncodeTime:     zapcore.ISO8601TimeEncoder,
    EncodeDuration: zapcore.SecondsDurationEncoder,
    EncodeCaller:   zapcore.ShortCallerEncoder,
  }
​
  return zapcore.NewConsoleEncoder(encoderConfig)
}
​
//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")
//  file, err := os.OpenFile("./test.log", os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
//  if err != nil {
//    log.Fatalf("open log file failed with error: %v", err)
//  }
//  // 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 getLogWriter() zapcore.WriteSyncer {
  // Logger is an io.WriteCloser that writes to the specified filename.
  // 日志记录器在第一次写入时打开或创建日志文件。如果文件存在并且小于MaxSize兆字节,则lumberjack将打开并追加该文件。
  // 如果该文件存在并且其大小为>= MaxSize兆字节,
  // 则通过将当前时间放在文件扩展名(或者如果没有扩展名则放在文件名的末尾)的名称中的时间戳中来重命名该文件。
  // 然后使用原始文件名创建一个新的日志文件。
  // 每当写操作导致当前日志文件超过MaxSize兆字节时,将关闭当前文件,重新命名,并使用原始名称创建新的日志文件。
  // 因此,您给Logger的文件名始终是“当前”日志文件。
  // 如果MaxBackups和MaxAge均为0,则不会删除旧的日志文件。
  lumberJackLogger := &lumberjack.Logger{
    // Filename是要写入日志的文件。备份日志文件将保留在同一目录下
    Filename: "./test.log",
    // MaxSize是日志文件旋转之前的最大大小(以兆字节为单位)。默认为100兆字节。
    MaxSize: 1, // M
    // MaxBackups是要保留的旧日志文件的最大数量。默认是保留所有旧的日志文件(尽管MaxAge仍然可能导致它们被删除)。
    MaxBackups: 5, // 备份数量
    // MaxAge是根据文件名中编码的时间戳保留旧日志文件的最大天数。
    // 请注意,一天被定义为24小时,由于夏令时、闰秒等原因,可能与日历日不完全对应。默认情况下,不根据时间删除旧的日志文件。
    MaxAge: 30, // 备份天数
    // Compress决定是否应该使用gzip压缩旋转的日志文件。默认情况下不执行压缩。
    Compress: false, // 是否压缩
  }
​
  return zapcore.AddSync(lumberJackLogger)
}
​
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()
  }
}
​
Code/go/zap_demo via   v1.20.3 via   base 
➜ go run main.go 
[GIN-debug] [WARNING] Running in "debug" mode. Switch to "release" mode in production.
 - using env:   export GIN_MODE=release
 - using code:  gin.SetMode(gin.ReleaseMode)
​
[GIN-debug] GET    /hello                    --> main.main.func1 (3 handlers)
[GIN-debug] [WARNING] You trusted all proxies, this is NOT safe. We recommend you to set a value.
Please check https://pkg.go.dev/github.com/gin-gonic/gin#readme-don-t-trust-all-proxies for details.
[GIN-debug] Environment variable PORT is undefined. Using port :8080 by default
[GIN-debug] Listening and serving HTTP on :8080
​

test.log

2023-06-17T14:17:08.553+0800  info  zap_demo/main.go:42 test lumberjack for log rotate....
2023-06-17T16:48:25.600+0800  info  zap_demo/main.go:76 /hello  {"status": 200, "method": "GET", "path": "/hello", "query": "", "ip": "::1", "user-agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36", "errors": "", "cost": 0.000057417}
2023-06-17T16:48:25.753+0800  info  zap_demo/main.go:76 /favicon.ico  {"status": 404, "method": "GET", "path": "/favicon.ico", "query": "", "ip": "::1", "user-agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36", "errors": "", "cost": 0.000000541}
​