How to use transaction by sequelize in my node js - sql

Question

While converting legacy long sql procedure to sequelizer, I met trouble to make transaction to my async functions.
I read sequelizer's transaction documents. But failed to understand clearly.
Here is my code.
const models = require('../models/models.js');
const sequelize = models.Sequelize;
async function isExistFeeHist(dansokSeqNo) {
log.debug("isExistFeeHist()");
let feeHist = await models.FeeHist.findOne({
where: {
DansokSeqNo: dansokSeqNo,
FeeStatus: {[Op.ne]: null}, //is not null
DelYN: false
}
});
return !!feeHist;
}
async function isPaid(dansokSeqNo) {
...
}
async function getNextDansokHistSerialNo(dansokSeqNo) {
...
}
async function getVBankSeqNo(dansokSeqNo) {
...
}
async function updateVBankList(dansokSeqNo, vBankSeqNo) {
...
}
//check if can cancel
async function checkCancelable(dansokSeqNo) {
log.debug("checkCancelable() ", dansokSeqNo);
if (await isExistFeeHist(dansokSeqNo)) {
let e = {status:400, message: 'already imposed dansokSeqNo ' + dansokSeqNo };
return Promise.reject({status:400, message: e.message });
}
if (await isPaid(dansokSeqNo)) {
let e = {status:400, message: 'already paid dansokSeqNo ' + dansokSeqNo };
return Promise.reject({status:400, message: e.message });
}
return Promise.resolve();
}
....
async function doCancel(dansokSeqNo, cancelCauseCode, histMemo) {
try {
await checkCancelable(dansokSeqNo);
//// <== Here I want to start transaction
let nextDansokSerialNo = await getNextDansokHistSerialNo(dansokSeqNo);
let dansokHist = await insertNewDansokHist(dansokSeqNo, nextDansokSerialNo, cancelCauseCode, histMemo);
await updateDansokHist(dansokSeqNo, cancelCauseCode);
let vBankSeqNo = await getVBankSeqNo(dansokSeqNo);
if (vBankSeqNo > 0) {
await updateVBankList(dansokSeqNo, vBankSeqNo);
let vBankList = await getVBankList(dansokSeqNo);
}
// <== Here I want to commit transaction
} catch (e) {
// <== Here I want to rollback transaction
return Promise.reject({status:e.status, message: e.message });
}
}
exports.cancelDansok = function (req, res) {
res.setHeader("Content-Type", "application/json; charset=utf-8");
...
jwtAcessAuth(accessToken)
.then((decoded) => {
log.info("jwt success, ", decoded);
worker = decoded.loginName;
return doCancel(dansokSeqNo, cancelCauseCode, histMemo);
})
.then(() => {
res.status(200).json({ message: 'cancelDansok success.' });
})
.catch(e => {
return res.status(e.status).json(e);
});
};
My function is assembled with several async functions. And it need to bind one transaction.
What is the best practice to use transaction in my several async await functions?

Answer 1

Here is the best example provided by Sequlize for Transaction :
All you need to care is pass transaction to next level of chaining
return sequelize.transaction(function (t) {
// chain all your queries here. make sure you return them.
return User.create({
firstName: 'Abraham',
lastName: 'Lincoln'
}, {transaction: t}).then(function (user) {
return user.setShooter({
firstName: 'John',
lastName: 'Boothe'
}, {transaction: t});
});
}).then(function (result) {
// Transaction has been committed
// result is whatever the result of the promise chain returned to the transaction callback
}).catch(function (err) {
// Transaction has been rolled back
// err is whatever rejected the promise chain returned to the transaction callback
});
For more details : Transactions