zing•4d ago

Sequential queue processing with Deno KV listenQueue?

I'm working on an API endpoint that needs to process lots of calls every second. I want to make this call asynchronous so that the API returns fast and I can offload the data to be processed in the background, so I thought of using Deno.kv queues(https://docs.deno.com/deploy/kv/manual/queue_overview/). The only issue is that there is a lot of async code inside the processing jobs, and when I queue up a lot of them they seem to overlap in processing, which causes issues when accessing shared resources(db connections specifically). Is there a way to make kv.listenQueue process each entry in sequence? This is effectively my queue code:

const kv = await Deno.openKv();

kv.listenQueue(async (msg: EvaluateRequest) => { await service.evaluate(msg) })

const kv = await Deno.openKv();

kv.listenQueue(async (msg: EvaluateRequest) => { await service.evaluate(msg) })

1 Reply

eli•20h ago

I have the same question. You may also want to note that the docs explicitly warn about the lack of guaranteed in-order processing, so you could potentially process the requests themselves out of sequence at high throughput, if that matters to you.