I have a large message submitted to a rest service, it could be 100k or 50mb. I need to process it asynchronously, and it looks like the transactional outbox event pattern is suitable for my needs.
Effectively, my service would commit the data to a database, along with an event record in a single transaction. A process would poll for events, and push the event to a message queue. THe event contains a reference to the data in the db, usually through a unique identifier of some sort. The consumer of the queue would query the data from the database, do whatever it needs to do and then remove the event record from the database.
This pattern is well documented. Here and here are two places.
I have a reasonable understanding of how one could implement this on-premis, in a .net/sql server environment that we are familiar with. In azure what would this look like? are there other ways I can transitionally write to the database and a queue that do not require the outbox pattern, or following the outbox pattern, what would be the mechanism that polls for events in the db, and what would provide the queue service?
Usually if you want to use the transactional outbox event pattern in azure you can use a logic app or an azure function to get events in the db and send them to the queue. Doing that would be great if you use cosmos change feed so that your architecture is also reactive and will perform well with less resource consumption.
To avoid this pattern well....you should find a queue in azure that is able to be in transaction with your db and for what I know is not possible at least that you don ' t use a 3rd part queue .