package main

import (
    "fmt"

    "github.com/go-xorm/xorm"

    "github.com/gogap/xorm_ext"
)

type User struct {
    UserName string
    Password string
}

type UserRepo interface {
    GetUser() string
}

type DBUserRepo struct {
    xorm_ext.DBRepo
}

func NewUserRepo(ormEngines map[string]*xorm.Engine) *DBUserRepo {
    repo := new(DBUserRepo)
    repo.SetEngines(ormEngines)
    return repo
}

func (p *DBUserRepo) GetUser() string {
    //p.Session().Query(sqlStr, ...)
    return "unknown"
}

func main() {

    engines := map[string]*xorm.Engine{xorm_ext.REPO_DEFAULT_ENGINE: new(xorm.Engine)}

    userRepo := NewUserRepo(engines)

    dbTXCommitter := new(xorm_ext.DBTXCommiter)

    logicFunc := func(repos []interface{}) (err error) {
        fmt.Println("enter logic")

        var uRepo UserRepo
        for _, repo := range repos {
            switch repo := repo.(type) {
            case UserRepo:
                {
                    //this userRepo is a new instance of DBUserRepo
                    fmt.Println("get new user repo")
                    uRepo = repo
                }
            }
        }

        userName := uRepo.GetUser()
        fmt.Println(userName)

        return
    }

    err := dbTXCommitter.Transaction(logicFunc, userRepo)
    //Or
    //err := dbTXCommitter.TransactionUsing("xormEngineName", userRepo, logicFunc)
    if err != nil {
        fmt.Println(err)
    }
}