手把手，带你从零封装Gin框架（十一）：使用文件记录错误日志 & 跨域处理

前言

Gin 框架的日志默认是在控制台输出，本篇将使用 Gin 提供的 RecoveryWithWriter() 方法，封装一个中间件，使用 lumberjack 作为的写入器，将错误日志写入文件中；同时使用 github.com/gin-contrib/cors ，作下跨域处理。

安装

go get -u gopkg.in/natefinch/lumberjack.v2
go get github.com/gin-contrib/cors

Recovery 中间件

在 app/common/response/response.go 文件中，添加 ServerError() 方法，作为 RecoveryFunc

package response

import (
    "github.com/gin-gonic/gin"
    "jassue-gin/global"
    "net/http"
    "os"
)

// ...

func ServerError(c *gin.Context, err interface{}) {
    msg := "Internal Server Error"
    // 非生产环境显示具体错误信息
    if global.App.Config.App.Env != "production" && os.Getenv(gin.EnvGinMode) != gin.ReleaseMode {
        if _, ok := err.(error); ok {
            msg = err.(error).Error()
        }
    }
    c.JSON(http.StatusInternalServerError, Response{
        http.StatusInternalServerError,
        nil,
        msg,
    })
    c.Abort()
}
// ...

新建 app/middleware/recovery.go 文件，编写：

package middleware

import (
    "github.com/gin-gonic/gin"
    "gopkg.in/natefinch/lumberjack.v2"
    "jassue-gin/app/common/response"
    "jassue-gin/global"
)

func CustomRecovery() gin.HandlerFunc {
    return gin.RecoveryWithWriter(
        &lumberjack.Logger{
            Filename:   global.App.Config.Log.RootDir + "/" + global.App.Config.Log.Filename,
            MaxSize:    global.App.Config.Log.MaxSize,
            MaxBackups: global.App.Config.Log.MaxBackups,
            MaxAge:     global.App.Config.Log.MaxAge,
            Compress:   global.App.Config.Log.Compress,
        },
        response.ServerError)
}

CORS 跨域处理

新建 app/middleware/cors.go 文件，编写：

package middleware

import (
    "github.com/gin-contrib/cors"
    "github.com/gin-gonic/gin"
)

func Cors() gin.HandlerFunc {
    config := cors.DefaultConfig()
    config.AllowAllOrigins = true
    config.AllowHeaders = []string{"Origin", "Content-Length", "Content-Type", "Authorization"}
    config.AllowCredentials = true
    config.ExposeHeaders = []string{"New-Token", "New-Expires-In", "Content-Disposition"}

    return cors.New(config)
}

使用中间件

在 bootstrap/router.go 文件，编写：

func setupRouter() *gin.Engine {
    if global.App.Config.App.Env == "production" {
        gin.SetMode(gin.ReleaseMode)
    }
    router := gin.New()
    router.Use(gin.Logger(), middleware.CustomRecovery())

    // 跨域处理
    // router.Use(middleware.Cors())

    // ...
}

测试

为了演示，这里我故意将数据库配置写错，请求登录接口，中间件成功生效

接着查看 storage/logs/app.log 文件，错误信息成功写入到文件，内容如下：

2021/11/21 20:40:18 [Recovery] 2021/11/21 - 20:40:18 panic recovered:
POST /api/auth/login HTTP/1.1
Host: localhost:8888
Accept: */*
Accept-Encoding: gzip, deflate
Cache-Control: no-cache
Connection: keep-alive
Content-Length: 51
Content-Type: application/json
Postman-Token: 30136d3a-9a7d-43ff-bd6e-8f408dd20a7e
User-Agent: PostmanRuntime/7.18.0


runtime error: invalid memory address or nil pointer dereference
/usr/local/go/src/runtime/panic.go:221 (0x104a9c6)
	panicmem: panic(memoryError)
/usr/local/go/src/runtime/signal_unix.go:735 (0x104a996)
	sigpanic: panicmem()
/Users/sjj/go/pkg/mod/gorm.io/gorm@v1.21.16/gorm.go:355 (0x1537ed8)
	(*DB).getInstance: if db.clone > 0 {
/Users/sjj/go/pkg/mod/gorm.io/gorm@v1.21.16/chainable_api.go:146 (0x152efdb)
	(*DB).Where: tx = db.getInstance()
/Users/sjj/go/src/jassue-gin/app/services/user.go:31 (0x17a963e)
	(*userService).Login: err = global.App.DB.Where("mobile = ?", params.Mobile).First(&user).Error
/Users/sjj/go/src/jassue-gin/app/controllers/app/auth.go:37 (0x17aab7b)
	Login: if err, user := services.UserService.Login(form); err != nil {
/Users/sjj/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/context.go:165 (0x1797681)
	(*Context).Next: c.handlers[c.index](c)
/Users/sjj/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/recovery.go:99 (0x179766c)
	CustomRecoveryWithWriter.func1: c.Next()
/Users/sjj/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/context.go:165 (0x17968e6)
	(*Context).Next: c.handlers[c.index](c)
/Users/sjj/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/logger.go:241 (0x17968c9)
	LoggerWithConfig.func1: c.Next()
/Users/sjj/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/context.go:165 (0x1795e1d)
	(*Context).Next: c.handlers[c.index](c)
/Users/sjj/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/gin.go:489 (0x1795aa5)
	(*Engine).handleHTTPRequest: c.Next()
/Users/sjj/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/gin.go:445 (0x1795604)
	(*Engine).ServeHTTP: engine.handleHTTPRequest(c)
/usr/local/go/src/net/http/server.go:2878 (0x129e49a)
	serverHandler.ServeHTTP: handler.ServeHTTP(rw, req)
/usr/local/go/src/net/http/server.go:1929 (0x1299b47)
	(*conn).serve: serverHandler{c.server}.ServeHTTP(w, w.req)
/usr/local/go/src/runtime/asm_amd64.s:1581 (0x1065ac0)
	goexit: BYTE	$0x90	// NOP