[系列] - go-gin-api 路由中间件 - 日志记录（三）

概述

首先同步下项目概况：

上篇文章分享了，规划项目目录和参数验证，其中参数验证使用的是 validator.v8 版本，现已更新到 validator.v9 版本，最新代码查看 github 即可。

这篇文章咱们分享：路由中间件 - 日志记录。

日志是特别重要的一个东西，方便我们对问题进行排查，这篇文章我们实现将日志记录到文本文件中。

这是我规划的，需要记录的参数：

- request 请求数据
    - request_time
    - request_method
    - request_uri
    - request_proto
    - request_ua
    - request_referer
    - request_post_data
    - request_client_ip

- response 返回数据
    - response_time
    - response_code
    - response_msg
    - response_data

- cost_time 花费时间

Gin 框架中自带 Logger 中间件，我们了解下框架中自带的 Logger 中间件是否满足我们的需求？

gin.Logger()

我们先使用 gin.Logger() 看看效果。

在 route.go SetupRouter 方法中增加代码：

engine.Use(gin.Logger())

运行后多请求几次，日志输出在命令行中：

[GIN] 2019/08/30 - 21:24:16 | 200 |     178.072µs |             ::1 | GET      /ping
[GIN] 2019/08/30 - 21:24:27 | 200 |     367.997µs |             ::1 | POST     /product
[GIN] 2019/08/30 - 21:24:28 | 200 |    2.521592ms |             ::1 | POST     /product

先解决第一个问题，怎么将日志输出到文本中？

在 route.go SetupRouter 方法中增加代码：

f, _ := os.Create(config.AppAccessLogName)
gin.DefaultWriter = io.MultiWriter(f)
engine.Use(gin.Logger())

运行后多请求几次，日志输出在文件中：

[GIN] 2019/08/30 - 21:36:07 | 200 |     369.023µs |             ::1 | GET      /ping
[GIN] 2019/08/30 - 21:36:08 | 200 |      27.585µs |             ::1 | GET      /ping
[GIN] 2019/08/30 - 21:36:10 | 200 |      14.302µs |             ::1 | POST     /product

虽然记录到文件成功了，但是记录的参数不是我们想要的样子。

怎么办呢？

我们需要自定义一个日志中间件，按照我们需要的参数进行记录。

自定义 Logger()

middleware/logger/logger.go

package logger

import (
    "bytes"
    "encoding/json"
    "fmt"
    "github.com/gin-gonic/gin"
    "go-gin-api/app/config"
    "go-gin-api/app/util"
    "log"
    "os"
)

type bodyLogWriter struct {
    gin.ResponseWriter
    body *bytes.Buffer
}
func (w bodyLogWriter) Write(b []byte) (int, error) {
    w.body.Write(b)
    return w.ResponseWriter.Write(b)
}
func (w bodyLogWriter) WriteString(s string) (int, error) {
    w.body.WriteString(s)
    return w.ResponseWriter.WriteString(s)
}

func SetUp() gin.HandlerFunc {
    return func(c *gin.Context) {
        bodyLogWriter := &bodyLogWriter{body: bytes.NewBufferString(""), ResponseWriter: c.Writer}
        c.Writer = bodyLogWriter

        //开始时间
        startTime := util.GetCurrentMilliTime()

        //处理请求
        c.Next()

        responseBody := bodyLogWriter.body.String()

        var responseCode int
        var responseMsg  string
        var responseData interface{}

        if responseBody != "" {
            response := util.Response{}
            err := json.Unmarshal([]byte(responseBody), &response)
            if err == nil {
                responseCode = response.Code
                responseMsg  = response.Message
                responseData = response.Data
            }
        }

        //结束时间
        endTime := util.GetCurrentMilliTime()

        if c.Request.Method == "POST" {
            c.Request.ParseForm()
        }

        //日志格式
        accessLogMap := make(map[string]interface{})

        accessLogMap["request_time"]      = startTime
        accessLogMap["request_method"]    = c.Request.Method
        accessLogMap["request_uri"]       = c.Request.RequestURI
        accessLogMap["request_proto"]     = c.Request.Proto
        accessLogMap["request_ua"]        = c.Request.UserAgent()
        accessLogMap["request_referer"]   = c.Request.Referer()
        accessLogMap["request_post_data"] = c.Request.PostForm.Encode()
        accessLogMap["request_client_ip"] = c.ClientIP()

        accessLogMap["response_time"] = endTime
        accessLogMap["response_code"] = responseCode
        accessLogMap["response_msg"]  = responseMsg
        accessLogMap["response_data"] = responseData

        accessLogMap["cost_time"] = fmt.Sprintf("%vms", endTime - startTime)

        accessLogJson, _ := util.JsonEncode(accessLogMap)

        if f, err := os.OpenFile(config.AppAccessLogName, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0666); err != nil {
            log.Println(err)
        } else {
            f.WriteString(accessLogJson + "\n")
        }
    }
}

运行后多请求几次，日志输出在文件中：

{"cost_time":"0ms","request_client_ip":"::1","request_method":"GET","request_post_data":"","request_proto":"HTTP/1.1","request_referer":"","request_time":1567172568233,"request_ua":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36","request_uri":"/ping","response_code":1,"response_data":null,"response_msg":"pong","response_time":1567172568233}
{"cost_time":"0ms","request_client_ip":"::1","request_method":"GET","request_post_data":"","request_proto":"HTTP/1.1","request_referer":"","request_time":1567172569158,"request_ua":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36","request_uri":"/ping","response_code":1,"response_data":null,"response_msg":"pong","response_time":1567172569158}
{"cost_time":"0ms","request_client_ip":"::1","request_method":"POST","request_post_data":"name=admin","request_proto":"HTTP/1.1","request_referer":"","request_time":1567172629565,"request_ua":"PostmanRuntime/7.6.0","request_uri":"/product","response_code":-1,"response_data":null,"response_msg":"Key: 'ProductAdd.Name' Error:Field validation for 'Name' failed on the 'NameValid' tag","response_time":1567172629565}