How to use golang to use mysql database

1. Dependency package

import (
    "database/sql"
    "fmt"
    _ "github.com/go-sql-driver/mysql"
)

If you forget to import the mysql dependency package, mysql will not open

2.main.go

package main

import (
    _ "container_cloud/pkg/config"
    "container_cloud/pkg/utils/httputil"
    "container_cloud/routers"
    "database/sql"
    "fmt"
    _ "github.com/go-sql-driver/mysql"
    "net/http"
    "time"
)

func init() {
    httputil.InitHttpTool()
}

// mysql
const (
    USERNAME = "root"
    PASSWORD = "Admin123"
    NETWORK  = "tcp"
    // TODO  本地调试时放开
    /*SERVER   = "192.168.103.48"
    PORT     = 43306*/

    // TODO 部署到环境时放开
    SERVER   = "192.168.66.4"
    PORT     = 3306
    DATABASE = "container_cloud"
)

func main() {
    var err error
    dsn := fmt.Sprintf("%s:%s@%s(%s:%d)/%s?parseTime=1&multiStatements=1&charset=utf8mb4&collation=utf8mb4_unicode_ci", USERNAME, PASSWORD, NETWORK, SERVER, PORT, DATABASE)

    db, err := sql.Open("mysql", dsn)
    if err != nil {
        fmt.Printf("Open mysql failed,err:%v\n", err)
        return
    }
    //最大连接周期，超过时间的连接就close
    db.SetConnMaxLifetime(100 * time.Second)
    //设置最大连接数
    db.SetMaxOpenConns(100)
    //设置闲置连接数
    db.SetMaxIdleConns(16)

    defer db.Close()

    container := routers.InitApiRouter(db)
    server := &http.Server{Addr: ":8090", Handler: container}
    server.ListenAndServe()
}

Some settings of the database

3.db object injection into ApiRouter

Modules that need to use the database need to be passed db object

4. The register layer passes the db to the controller

package v1alpha1

import (
    "container_cloud/pkg/api"
    "container_cloud/pkg/apiserver/query"
    "container_cloud/pkg/apiserver/runtime"
    "container_cloud/pkg/controller"
    "container_cloud/pkg/domain"
    "database/sql"
    "github.com/emicklei/go-restful"
    "k8s.io/apimachinery/pkg/runtime/schema"
    "net/http"
)

const (
    GroupName = "order.ictnj.io"
    Version   = "v1alpha1"
)

var GroupVersion = schema.GroupVersion{Group: GroupName, Version: Version}

func AddToContainer(db *sql.DB) *restful.WebService{
    ws := runtime.NewWebService(GroupVersion)
    orderController := controller.NewOrderController(db)

    // 创建订单接口，pvc创建、负载创建的时候，是在特定命名空间下。（其实请求入参中也有命名空间字段，资源创建的时候也可以从入参中获取）
    ws.Route(ws.POST("/namespaces/{namespace}/orders").
        To(orderController.CreateOrder).
        Param(ws.PathParameter("namespace", "namespace name")).
        Returns(http.StatusOK, api.StatusOK, map[string]string{}).
        Doc("create order."))

    return ws
}

5. The controller layer passes the db to the service or mapper

type orderController struct {
    Db *sql.DB
}

func NewOrderController(db *sql.DB) *orderController{
    return &orderController{Db: db}
}

// 再创建订单
    orderService := service.NewOrderService(o.Db)
    orderService.CreateOrder(order)
    result := map[string]string{"message": "success"}
    response.WriteEntity(result)

6. Architecture analysis diagram

When the logic is relatively simple, you can directly skip the service, and the controller directly calls mapper

7.mapper example

package service

import (
    "container_cloud/pkg/api"
    "container_cloud/pkg/apiserver/query"
    "container_cloud/pkg/domain"
    "database/sql"
    "encoding/json"
    "fmt"
    "github.com/google/uuid"
    "k8s.io/klog"
    "strings"
    "time"
)

type OrderService struct {
    Db *sql.DB
}

func NewOrderService(db *sql.DB) *OrderService{
    return &OrderService{Db: db}

}
func (o *OrderService) CreateOrder(order domain.Order) {
    order.CreateTime = time.Now()
    var orderType uint8 = 1
    order.OrderType = &orderType
    uuid,_ := uuid.NewRandom()
    order.Id = strings.ReplaceAll(uuid.String(), "-", "")

    jsonbyte, _ := json.Marshal(order.OrderItem)
    order.OrderItemJson = string(jsonbyte)

    o.insertData(order)
}

func (o *OrderService) insertData(order domain.Order) {
    stmt, _ := o.Db.Prepare(`INSERT INTO t_order (id, username, service_type, order_type, status, reason, order_item, create_time) VALUES (?, ?, ?, ?, ?, ?, ?, ?)`)
    defer stmt.Close()

    ret, err := stmt.Exec(order.Id, order.Username, order.ServiceType, order.OrderType, order.Status, order.Reason, order.OrderItemJson, order.CreateTime)
    if err != nil {
        fmt.Printf("insert data error: %v\n", err)
        return
    }
    if LastInsertId, err := ret.LastInsertId(); nil == err {
        fmt.Println("LastInsertId:", LastInsertId)
    }
    if RowsAffected, err := ret.RowsAffected(); nil == err {
        fmt.Println("RowsAffected:", RowsAffected)
    }
}

func (o *OrderService) ListOrders(query *query.Query, username string) (*api.ListResult, error){
    // 查询总数量
    totalRow, err := o.Db.Query("SELECT COUNT(*) FROM t_order WHERE username = ?", username)
    if err != nil {
        klog.Error("query orders count error", err)
        return nil, err
    }
    total := 0
    for totalRow.Next() {
        err := totalRow.Scan(
            &total,
        )
        if err != nil {
            klog.Error("query orders count error", err)
            continue
        }
    }
    totalRow.Close()

    // 查询订单列表
    rows, err := o.Db.Query("select * from t_order where username = ? order by create_time desc limit ? offset ? ", username, query.Pagination.Limit, query.Pagination.Offset)
    defer func() {
        if rows != nil {
            rows.Close()
        }
    }()
    if err != nil {
        klog.Error("query orders error", err)
        return nil, err
    }

    items := make([]interface{}, 0)
    for rows.Next() {
        order := new(domain.Order)
        err = rows.Scan(&order.Id, &order.Username, &order.ServiceType, &order.OrderType, &order.Status, &order.Reason, &order.OrderItemJson, &order.CreateTime)
        if err != nil {
            klog.Error("query orders error", err)
            return nil, err
        }
        order.OrderItemJson = ""
        items = append(items, *order)
    }

    return &api.ListResult{
        TotalItems: total,
        Items:      items,
    }, nil

}

func (o *OrderService) GetOrder(id string) (*domain.Order, error) {
    order := new(domain.Order)
    row := o.Db.QueryRow("select order_item from t_order where id = ?", id)
    if err := row.Scan(&order.OrderItemJson); err != nil {
        klog.Error(err)
        return nil, err
    }
    orderItems := &[]domain.OrderItem{}
    json.Unmarshal([]byte(order.OrderItemJson), orderItems)

    order.OrderItemJson = ""
    order.OrderItem = *orderItems
    return order, nil
}


func (o *OrderService) ListUserOrders(username string) (*[]domain.Order, error){
    // 查询订单列表
    rows, err := o.Db.Query("select * from t_order where username = ? order by create_time desc", username)
    defer func() {
        if rows != nil {
            rows.Close()
        }
    }()
    if err != nil {
        klog.Error("query orders error", err)
        return nil, err
    }
    items :=  make([]domain.Order,0)
    for rows.Next() {
        order := new(domain.Order)
        err = rows.Scan(&order.Id, &order.Username, &order.ServiceType, &order.OrderType, &order.Status, &order.Reason, &order.OrderItemJson, &order.CreateTime)
        if err != nil {
            klog.Error("query orders error", err)
            return nil, err
        }
        order.OrderItemJson = ""
        items = append(items, *order)
    }

    return &items,nil
}

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