Incrementing/decrementing in Collections - avoiding race conditions - Threads

I have a Collection with a list of items and our stock level for them. When someone makes an order, I need to decrement stock, and when new stock is added, I need to increment stock.

The simplest way would be to getDocument, then updateDocument with stock-1, but that would be an issue if there are two orders at the same time.

The only method I can think of to deal with this is: Create a new record in a collection order_updates. Check order_updates for any records created before the one I just created. If there are, wait 0.5 seconds and check again. Once there are no more records before my new one, get the current stock level and update it. Delete the order_updates record.

This seems a bit roundabout, though - does anyone have any better ways to deal with this? TIA!

TL;DR

The user is looking for a way to increment/decrement stock levels in a collection without facing race conditions. Currently, they are using a solution involving creating a new record in a separate collection and checking for any previous records before updating the stock level. However, they are seeking a more efficient approach. Solution: One possible solution is to implement a lock mechanism by creating a separate collection for locks. When a process wants to obtain a lock, it creates a document with the resource's ID. If the document is created successfully, the lock is obtained. If another process tries to obtain the same lock, it will receive an error. Once the process

One way to create a lock is to create a locks collection. A process that wants to obtain a lock will create a document with id == id of the resource. If it can create the document successfully, it has obtained the lock. If any other document tries to obtain a lock, they'll get an error because the document already exists with the same id. When the process that obtained the lock is done, it can delete the lock document to release the lock