137 lines
4.6 KiB
Go
137 lines
4.6 KiB
Go
package dtmcli
|
||
|
||
import (
|
||
"context"
|
||
"database/sql"
|
||
"encoding/json"
|
||
"fmt"
|
||
|
||
"github.com/gin-gonic/gin"
|
||
"github.com/sirupsen/logrus"
|
||
"github.com/yedf/dtm/common"
|
||
)
|
||
|
||
// BusiFunc type for busi func
|
||
type BusiFunc func(db *sql.DB) (interface{}, error)
|
||
|
||
// TransInfo every branch info
|
||
type TransInfo struct {
|
||
TransType string
|
||
Gid string
|
||
BranchID string
|
||
BranchType string
|
||
}
|
||
|
||
func (t *TransInfo) String() string {
|
||
return fmt.Sprintf("transInfo: %s %s %s %s", t.TransType, t.Gid, t.BranchID, t.BranchType)
|
||
}
|
||
|
||
// TransInfoFromReq construct transaction info from request
|
||
func TransInfoFromReq(c *gin.Context) *TransInfo {
|
||
ti := &TransInfo{
|
||
TransType: c.Query("trans_type"),
|
||
Gid: c.Query("gid"),
|
||
BranchID: c.Query("branch_id"),
|
||
BranchType: c.Query("branch_type"),
|
||
}
|
||
if ti.TransType == "" || ti.Gid == "" || ti.BranchID == "" || ti.BranchType == "" {
|
||
panic(fmt.Errorf("invlid trans info: %v", ti))
|
||
}
|
||
return ti
|
||
}
|
||
|
||
// BarrierModel barrier model for gorm
|
||
type BarrierModel struct {
|
||
common.ModelBase
|
||
TransInfo
|
||
}
|
||
|
||
func logExec(tx *sql.Tx, query string, args ...interface{}) (sql.Result, error) {
|
||
logrus.Printf("executing: "+query, args...)
|
||
return tx.Exec(query, args...)
|
||
}
|
||
|
||
func logQueryRow(tx *sql.Tx, query string, args ...interface{}) *sql.Row {
|
||
logrus.Printf("querying: "+query, args...)
|
||
return tx.QueryRow(query, args...)
|
||
}
|
||
|
||
// TableName gorm table name
|
||
func (BarrierModel) TableName() string { return "dtm_barrier.barrier" }
|
||
|
||
func insertBarrier(tx *sql.Tx, transType string, gid string, branchID string, branchType string, reason string) (int64, error) {
|
||
if branchType == "" {
|
||
return 0, nil
|
||
}
|
||
res, err := logExec(tx, "insert ignore into dtm_barrier.barrier(trans_type, gid, branch_id, branch_type, reason) values(?,?,?,?,?)", transType, gid, branchID, branchType, reason)
|
||
if err != nil {
|
||
return 0, err
|
||
}
|
||
return res.RowsAffected()
|
||
}
|
||
|
||
// ThroughBarrierCall 子事务屏障，详细介绍见 https://zhuanlan.zhihu.com/p/388444465
|
||
// db: 本地数据库
|
||
// transInfo: 事务信息
|
||
// bisiCall: 业务函数，仅在必要时被调用
|
||
// 返回值:
|
||
// 如果正常调用，返回bisiCall的结果
|
||
// 如果发生重复调用，则busiCall不会被重复调用，直接对保存在数据库中上一次的结果，进行unmarshal，通常是一个map[string]interface{}，直接作为http的resp
|
||
// 如果发生悬挂，则busiCall不会被调用，直接返回错误 {"dtm_result": "FAILURE"}
|
||
// 如果发生空补偿，则busiCall不会被调用，直接返回 {"dtm_result": "SUCCESS"}
|
||
func ThroughBarrierCall(db *sql.DB, transInfo *TransInfo, busiCall BusiFunc) (res interface{}, rerr error) {
|
||
tx, rerr := db.BeginTx(context.Background(), &sql.TxOptions{})
|
||
if rerr != nil {
|
||
return
|
||
}
|
||
defer func() {
|
||
logrus.Printf("result is %v error is %v", res, rerr)
|
||
if x := recover(); x != nil {
|
||
tx.Rollback()
|
||
panic(x)
|
||
} else if rerr != nil {
|
||
tx.Rollback()
|
||
} else {
|
||
tx.Commit()
|
||
}
|
||
}()
|
||
ti := transInfo
|
||
originType := map[string]string{
|
||
"cancel": "try",
|
||
"compensate": "action",
|
||
}[ti.BranchType]
|
||
originAffected, _ := insertBarrier(tx, ti.TransType, ti.Gid, ti.BranchID, originType, ti.BranchType)
|
||
currentAffected, rerr := insertBarrier(tx, ti.TransType, ti.Gid, ti.BranchID, ti.BranchType, ti.BranchType)
|
||
logrus.Printf("originAffected: %d currentAffected: %d", originAffected, currentAffected)
|
||
if (ti.BranchType == "cancel" || ti.BranchType == "compensate") && originAffected > 0 { // 这个是空补偿，返回成功
|
||
res = common.MS{"dtm_result": "SUCCESS"}
|
||
return
|
||
} else if currentAffected == 0 { // 插入不成功
|
||
var result sql.NullString
|
||
err := logQueryRow(tx, "select result from dtm_barrier.barrier where trans_type=? and gid=? and branch_id=? and branch_type=? and reason=?",
|
||
ti.TransType, ti.Gid, ti.BranchID, ti.BranchType, ti.BranchType).Scan(&result)
|
||
if err == sql.ErrNoRows { // 这个是悬挂操作，返回失败，AP收到这个返回，会尽快回滚
|
||
res = common.MS{"dtm_result": "FAILURE"}
|
||
return
|
||
}
|
||
if err != nil {
|
||
rerr = err
|
||
return
|
||
}
|
||
if result.Valid { // 数据库里有上一次结果，返回上一次的结果
|
||
res = json.Unmarshal([]byte(result.String), &res)
|
||
return
|
||
}
|
||
// 数据库里没有上次的结果，属于重复空补偿，直接返回成功
|
||
res = common.MS{"dtm_result": "SUCCESS"}
|
||
return
|
||
}
|
||
res, rerr = busiCall(db)
|
||
if rerr == nil { // 正确返回了，需要将结果保存到数据库
|
||
sval := common.MustMarshalString(res)
|
||
_, rerr = logExec(tx, "update dtm_barrier.barrier set result=? where trans_type=? and gid=? and branch_id=? and branch_type=?", sval,
|
||
ti.TransType, ti.Gid, ti.BranchID, ti.BranchType)
|
||
}
|
||
return
|
||
}
|