golang学习问题记录

1、err:go net bind: address already in use

//服务端设置端口复用+客户端绑定固定端口号
import(
	"syscall"
    "context"
    "golang.org/x/sys/unix" //仅限于Linux
)
cfg := net.ListenConfig{
    Control: func(network, address string, c syscall.RawConn) error {
        return c.Control(func(fd uintptr) {
            syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, unix.SO_REUSEADDR, 1)
            syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, unix.SO_REUSEPORT, 1)
        })
    },
}
tcp, err := cfg.Listen(context.Background(), "tcp", "127.0.0.1:1234")

2、websocket多客户端管理

​ 通过map保存客户端信息，通过ws.RemoteAddr().String()作为key区分不同的websocket连接；再为每一个客户端连接建立一个消息通道；

import (
	"sync"
	"github.com/gorilla/websocket"
)
type Msg struct {
	Data   chan []byte
	...
	Times   int64
}
var (
    Mmessage = make(map[string]Msg)
	Mclient  = make(map[string]*websocket.Conn)
	Mmux     sync.Mutex
)

3、日志按时间(24h)分割zap+file-rotatelogs

import (
	"io"
	rotatelogs "github.com/lestrrat-go/file-rotatelogs"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
)

func getLogWriter() zapcore.WriteSyncer {
    hook, err := rotatelogs.New(
		"./logs/log"+"_%Y-%m-%d %H:%M:%S.log",
		rotatelogs.WithLinkName("./logs/log"),
		rotatelogs.WithMaxAge(time.Hour*24*30),
		rotatelogs.WithRotationTime(time.Hour*24),
		rotatelogs.WithRotationSize(int64(10*1024*1024)),
    )
	if err != nil {
		panic(err)
	}
 	return zapcore.AddSync(hook)
}

4、 将401重定向到首页

import (
	"net/http"
	"github.com/gin-gonic/gin"
)
func main() {
    gin.SetMode(gin.ReleaseMode)
    router := gin.Default()
    router.LoadHTMLGlob("www/index.html") //加载html模板文件
	router.NoRoute(func(c *gin.Context) {
		c.HTML(http.StatusNotFound, "index.html", nil)
	})
    err := router.Run(":8080")
	if err != nil {
		log.Fatalln(err)
	}
}

5、sqlite模式设置

import (
	"log"
	"os"
	"time"

	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

func NewDB() (*gorm.DB) {
	var err error

	file, error := os.OpenFile("./logs/db.log", os.O_RDWR|os.O_CREATE, 0766)
	if error != nil {
	 	log.Println(error)
	}

	MyLog := logger.New(log.New(file, "\r\n", log.LstdFlags), logger.Config{
		SlowThreshold:             200 * time.Millisecond,
		LogLevel:                  logger.Warn,
		IgnoreRecordNotFoundError: true,
		Colorful:                  false,
	})

	mydb, err := gorm.Open(sqlite.Open("mydb.db"), &gorm.Config{
		Logger: MyLog,
		NowFunc: func() time.Time {
			return time.Now().Local()
		},
	})

	if err != nil {
        log.Println("db open err:" + err.Error())
	} else {
		// 启用 WAL 模式
		mydb.Exec("PRAGMA journal_mode=WAL;")
	}
	sqlDB, dbError := mydb.DB()
	if dbError != nil {
	 	log.Println("failed to create sqlDB", dbError.Error())
	}

	// SetMaxIdleConns 设置空闲连接池中连接的最大数量
	sqlDB.SetMaxIdleConns(10)

	// SetMaxOpenConns 设置打开数据库连接的最大数量。
	sqlDB.SetMaxOpenConns(100)

	log.Println("db open success")
	return mydb
}