现代微服务分布式事务完全指南 2026：Saga 模式 vs TCC vs XA + DTM 实战

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package main
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import (
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  "database/sql"
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  "net/http"
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  "github.com/dtm-labs/client/dtmcli"
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  "github.com/gin-gonic/gin"
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  _ "github.com/lib/pq"
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)
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var db *sql.DB
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func init() {
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  var err error
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  db, err = sql.Open("postgres", "postgres://postgres:postgres123@localhost:5432/business_db?sslmode=disable")
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  if err != nil {
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    panic(err)
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  }
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}
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func main() {
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  r := gin.Default()
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  // 1. 扣减库存正向操作 (Action)
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  r.POST("/api/stock/deduct", func(c *gin.Context) {
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    barrier, err := dtmcli.BarrierFromQuery(c.Request.URL.Query())
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    if err != nil {
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      c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
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      return
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    }
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    // 核心：在子事务屏障保护下执行扣库存
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    err = barrier.CallWithDB(db, func(tx *sql.Tx) error {
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      _, e := tx.Exec("UPDATE inventory SET stock = stock - 1 WHERE product_id = 'prod_01' AND stock >= 1")
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      return e
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    })
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    if err != nil {
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      c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
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      return
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    }
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    c.JSON(http.StatusOK, gin.H{"status": "SUCCESS"})
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  })
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  // 2. 恢复库存逆向补偿 (Compensate)
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  r.POST("/api/stock/compensate", func(c *gin.Context) {
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    barrier, _ := dtmcli.BarrierFromQuery(c.Request.URL.Query())
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    err := barrier.CallWithDB(db, func(tx *sql.Tx) error {
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      _, e := tx.Exec("UPDATE inventory SET stock = stock + 1 WHERE product_id = 'prod_01'")
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      return e
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    })
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    if err != nil {
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      c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
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      return
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    }
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    c.JSON(http.StatusOK, gin.H{"status": "SUCCESS"})
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  })
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  r.Run(":8081")
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}

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package main
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import (
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  "fmt"
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  "github.com/dtm-labs/client/dtmcli"
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)
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func main() {
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  dtmServer := "http://localhost:36789/api/dtmsvr"
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  gid := dtmcli.MustGenGid(dtmServer)
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  // 构建 Saga 全局事务
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  saga := dtmcli.NewSaga(dtmServer, gid).
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    // 步骤 1: 扣减库存 (正向 Action + 逆向 Cancel)
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    Add("http://localhost:8081/api/stock/deduct", "http://localhost:8081/api/stock/compensate", nil).
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    // 步骤 2: 扣减账户余额 (正向 Action + 逆向 Cancel)
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    Add("http://localhost:8082/api/account/deduct", "http://localhost:8082/api/account/compensate", nil)
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  // 提交 Saga 事务
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  err := saga.Submit()
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  if err != nil {
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    fmt.Printf("❌ Saga global transaction failed: %v\n", err)
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    return
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  }
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  fmt.Printf("✅ Saga global transaction submitted successfully! GID: %s\n", gid)
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}