Transaction is not working

[alickmail]

I am not able to use transaction for model update, the transaction.commit().then() is fired, but the data on google console did not updated.

I have tried the Model.update function without using transaction, the data on google console is updated successfully

i am following the example from gitbook:
Link

Here is update model code:

function transferCoins(fromUser, toUser, coins) {
  return new Promise((resolve, reject) => {
    let fromUserObj = fromUser.plain();
    let toUserObj = toUser.plain();

    let transaction = gstore.transaction();
    transaction.run().then(() => {
      User.update(fromUserObj.id, {
        name : 'asdsadfssssf',
        coins: fromUserObj.coins - 1000
      }, null, null, transaction);

      transaction.commit().then((x) => {
        resolve();
      }).catch(err => {
        console.log({err});
      });

      // User.update(toUserObj.id, toUserObj.coins + 1000, null, null, transaction);
    }).catch(err => {
      transaction.rollback();
      reject(err);
    });
  });
}

Here is the model file

const gstore = require('gstore-node')();
const Schema = gstore.Schema;
const Joi = require('joi');

const userSchema = new Schema({
  name        : {joi: Joi.string().required()},
  lastname    : {joi: Joi.string()},
  password    : {joi: Joi.string()},
  coins       : {joi: Joi.number().integer().min(0)},
  email       : {joi: Joi.string().email()},
  createdAt   : {joi: Joi.date()},
  access_token: {joi: [Joi.string(), Joi.number()]},
  birthyear   : {joi: Joi.number().integer().min(1900).max(2013)},
}, {joi: true});


const User = gstore.model('User', userSchema);

module.exports = User;

Please help, thanks!

[sebelga]

Hello,
Thanks for reporting, your code looks ok so I will try to reproduce and let you know.
cheers

[sebelga]

Hi @alickmail

I just released v5.0.0 that should fix this bug. There was indeed a bug in the Model.update() method when using transaction.

Once you update the gstore version (make sure you update how you instantiate gstore, there is a breaking change), you will need to make a small change in your code:

...
function transferCoins(fromUser, toUser, amount) {
    const transaction = gstore.transaction();
    return transaction.run()
        .then(async () => {
            await User.update(fromUser.entityKey.id, {
                coins: fromUser.coins - amount,
            }, null, null, transaction);

            await User.update(toUser.entityKey.id, {
                coins: toUser.coins + amount,
            }, null, null, transaction);

            return transaction.commit();
        }).catch((err) => {
            transaction.rollback();
            throw err;
        });
}


// ----------------------------
// Or without "async" and "waiting" if you already have fetched the entity data previously

function transferCoins(fromUser, toUser, amount) {
    const transaction = gstore.transaction();
    return transaction.run()
        .then(() => {
            const fromUserUpdated = new User({
                ...fromUser.entityData,
                coins: fromUser.coins - amount},
                fromUser.entityKey.id
            );

            const toUserUpdated = new User({
                ...toUser.entityData,
                coins: toUser.coins + amount},
                toUser.entityKey.id
            );

            fromUserUpdated.save(transaction);
            toUserUpdated.save(transaction);

            return transaction.commit();
        }).catch((err) => {
            transaction.rollback();
            throw err;
        });
}

[sebelga]

You use case made me think that it'd be useful to add a sort of updater() or increment functionality to dyncamically update a value.

Be careful that you might run in a race condition if 2 requests fetch the fromUser entity at the same time, (so they both have the same initial "coins" value) and then try to update the same user at slightly different times...
You might want to think in a way to "lock" an entity when fetching the user so when a second request tries to update the user and the lock version mismatch you cancel the second request.

Closing the issue. Feel free to reopen if you still have a problem.