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Discussion on: AWS Lambda SQS events with Serverless Framework

 
kbariotis profile image
Kostas Bariotis

Ah no I wasn't talking about order but rather the regulation flow. So I want the messages to wait in the queue until the worker can process them but with SQS/Lambda the messages won't wait since they are experiencing throttling and will fail and will either be removed or go to the DLQ.

But I liked you technique on preserving order. I haven't tried it, maybe I will in the future.

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piczmar_0 profile image
Marcin Piczkowski

Hmm.. I see. So maybe you could try the same technique here. When throttled message goes to DLQ you have a lambda function running in some scheduled interval which you set by experimenting with throttle rate, and this lambda will forward the message from DLQ back to original queue from which it could possibly be processed again and hopefully not throttled again.

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kbariotis profile image
Kostas Bariotis

I just created this repo and remembered of our discussion. This is how I managed to create a sequential processing pipeline with AWS SQS and Lambda on a Serverless project.

Let me know what you think! Thank you.

github.com/kbariotis/sqs-lambda-co...

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piczmar_0 profile image
Marcin Piczkowski

Nice :) I like it.

I tried to find out what happens to the CloudWatch event which is throttled, if it is retried or dropped but I could not see in docs, but I suppose it is more a problem of AWS what to do with high number of cumulated CloudWatch events which are continuously retried, rather than your problem, since setting of concurrency limit on Lambda to 1 provides that no more than 1 instance of this function will execute at certain time.

Nice wrap up. Thanks.