mirror of
https://gitee.com/dromara/mayfly-go
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128 lines
3.0 KiB
Go
128 lines
3.0 KiB
Go
package db
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import (
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"database/sql"
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"errors"
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"fmt"
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"mayfly-go/base/model"
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"mayfly-go/models"
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"strings"
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"sync"
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"time"
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_ "github.com/go-sql-driver/mysql"
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)
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var dbCache sync.Map
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// db实例
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type DbInstance struct {
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Id uint64
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Type string
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db *sql.DB
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}
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// 执行查询语句
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func (d *DbInstance) SelectData(sql string) ([]map[string]string, error) {
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sql = strings.Trim(sql, " ")
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if !strings.HasPrefix(sql, "SELECT") && !strings.HasPrefix(sql, "select") {
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return nil, errors.New("该sql非查询语句")
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}
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rows, err := d.db.Query(sql)
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if err != nil {
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return nil, err
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}
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// rows对象一定要close掉，如果出错，不关掉则会很迅速的达到设置最大连接数，
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// 后面的链接过来直接报错或拒绝，实际上也没有起效果
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defer func() {
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if rows != nil {
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rows.Close()
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}
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}()
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cols, _ := rows.Columns()
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// 这里表示一行填充数据
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scans := make([]interface{}, len(cols))
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// 这里表示一行所有列的值，用[]byte表示
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vals := make([][]byte, len(cols))
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// 这里scans引用vals，把数据填充到[]byte里
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for k := range vals {
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scans[k] = &vals[k]
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}
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result := make([]map[string]string, 0)
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for rows.Next() {
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// 不Scan也会导致等待，该链接实际处于未工作的状态，然后也会导致连接数迅速达到最大
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err := rows.Scan(scans...)
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if err != nil {
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return nil, err
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}
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// 每行数据
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rowData := make(map[string]string)
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// 把vals中的数据复制到row中
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for k, v := range vals {
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key := cols[k]
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// 这里把[]byte数据转成string
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rowData[key] = string(v)
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}
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//放入结果集
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result = append(result, rowData)
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}
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return result, nil
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}
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// 执行 update, insert, delete，建表等sql
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//
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// 返回影响条数和错误
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func (d *DbInstance) Exec(sql string) (int64, error) {
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res, err := d.db.Exec(sql)
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if err != nil {
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return 0, err
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}
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return res.RowsAffected()
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}
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// 关闭连接，并从缓存中移除
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func (d *DbInstance) Close() {
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d.db.Close()
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dbCache.Delete(d.Id)
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}
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// 获取dataSourceName
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func getDsn(d *models.Db) string {
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if d.Type == "mysql" {
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return fmt.Sprintf("%s:%s@%s(%s:%d)/%s", d.Username, d.Passowrd, d.Network, d.Host, d.Port, d.Database)
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}
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return ""
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}
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func GetDbInstance(id uint64) *DbInstance {
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// Id不为0，则为需要缓存
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needCache := id != 0
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if needCache {
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load, ok := dbCache.Load(id)
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if ok {
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return load.(*DbInstance)
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}
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}
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d := models.GetDbById(uint64(id))
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model.NotNil(d, "数据库信息不存在")
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DB, err := sql.Open(d.Type, getDsn(d))
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model.ErrIsNil(err, fmt.Sprintf("Open %s failed, err:%v\n", d.Type, err))
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perr := DB.Ping()
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if perr != nil {
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panic(model.NewBizErr(fmt.Sprintf("数据库连接失败: %s", perr.Error())))
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}
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// 最大连接周期，超过时间的连接就close
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DB.SetConnMaxLifetime(100 * time.Second)
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// 设置最大连接数
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DB.SetMaxOpenConns(5)
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// 设置闲置连接数
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DB.SetMaxIdleConns(1)
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dbi := &DbInstance{Id: id, Type: d.Type, db: DB}
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if needCache {
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dbCache.LoadOrStore(d.Id, dbi)
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}
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return dbi
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}
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