CODEWITHSUNDEEP
amazon-web-servicesaws-lambdaamazon-snsserverless-framework
Avneesh
Avneesh

Reputation: 355

Getting exponential backoff in AWS SNS with AWS Lambda

As it currently stands AWS SNS provides functionality for retrial(Linear, Geometric and Exponential backoff) with HTTP/HTTPS endpoints in case of a 5XX response returned from the endpoint.

Because of this my application architecture changes and I forcefully need to insert a API gateway between my SNS and Lambda so that in case of a failure I can return a 5XX status from the API gateway and utilise the retrial functionality of SNS.

But there is nothing mentioned for retrial mechanism with AWS lambda. Is there any way I can use the SNS retrial facilities for non-HTTP based subscriptions?

Thanks

Upvotes: 3

Views: 1406

Answers (1)

Avneesh
Avneesh

Reputation: 355

After a couple of hours of debugging and going through AWS documentation it seems that there is currently no way of getting exponential back of from AWS SNS for anything else apart from HTTP/HTTPS sources.

You can checkout the this.

As quoted in the documentation:

When a user calls the SNS Publish API on a topic that your Lambda function is subscribed to, Amazon SNS will call Lambda to invoke your function asynchronously. Lambda will then return a delivery status. If there was an error calling Lambda, Amazon SNS will retry invoking the Lambda function up to three times. After three tries, if Amazon SNS still could not successfully invoke the Lambda function, then Amazon SNS will send a delivery status failure message to CloudWatch.

Since there is a async invocation of the Lambda SNS will not care what the exit status of the lambda is. Hence, from the point of view of SNS, a successful invocation of the lambda is success enough and will not provide a failure event, hence no customised back off.

For now it seems, adding an HTTP endpoint is the only option.

Upvotes: 3

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