runzx / zx-transcation

transcation for mongodb simple service

mongoose 单机 实现 事务处理

1. 主要可靠实现 create, increment, remove
2. 此流程不能锁表, update 在并发时 rollback 回滚 后可能数据不正确 (update 出错到回滚间如并发有修改操作，则会丢失此部分)
3. 事务流程可以记录 在数据库中(TransactionModel), 可通过此回滚
4. modelName 集合要先定义

// test/demo.js
import { Transaction, mongoose, Schema } from "../src/index.js"
const User = mongoose.model(
  "User", // modelName
  new Schema({ name: String, age: Number, points: Number })
)

const uri = "mongodb://centos7:27017/demo"
mongoose.connect(uri, null, () => console.log("mongoose connect:" + uri))
mongoose.connection.on("error", (err) => console.error(err))

const useDB = false
const t = new Transaction(useDB) // false 不记录 事务流程 在数据库中

const zxId = t.insert("User", { name: "zx" })
const mmId = t.insert("User", { name: "mm" })

t.increment("User", zxId, { points: 100 })
t.increment("User", zxId, { points: "-20" })
t.increment("User", mmId, { points: "20.0" })
t.increment("User", "fakeId", { points: "-20" })
try {
  t.run()
} catch (e) {
  t.rollback()
}

从数据库中取记录 重新执行 或 回滚

import { Transaction, mongoose, Schema } from "../src/index.js"
const User = mongoose.model(
  "User",
  new Schema({ name: String, age: Number, points: Number })
)

const uri = "mongodb://centos7:27017/demo"
mongoose.connect(uri, null, () => console.log("mongoose connect:" + uri))
mongoose.connection.on("error", (err) => console.error(err))

async function start() {
  const t = new Transaction(true)
  let res = await t.loadDbTransaction("631c84a3100479a55b692400")
  try {
    res = await t.run()
  } catch (e) {
    res = await t.rollback()
  }
  console.log(res)
}
start()

// 事务记录
const transaction = new Transaction(true)
const transId = await transaction.getTransactionId()
// 保存 记录
const transId = await transaction.saveOperations()
// 读取 记录
await transaction.loadDbTransaction(transId)

operation

Operation = {
  type: "insert", // 'insert', 'update', 'remove', 'increment'
  rollbackType: "remove", // execute for rollback type: 'remove', 'update', 'insert' ('increment' -> 'update')
  model: {}, // mongoose model instance
  modelName: "User", // mongoose model name
  oldModel: null, // 'mongoose model instance beforce transcation if exists',
  findId: "xxx", // ObjectId
  data: {},
  options: {}, // query options, {new: false}
  status: Status.pending,
}

Status = ["Pending", "Success", "Error", "Rollback", "ErrRollback"]

参考

1. "mongoose-transactions"