Lambda Gateway API Response

Question

I use the Gateway-to-Lambda API for several microservices, but in at least one case, the service will take 20-30 seconds, so in such cases I would like to send an immediate response to the client, something like:

status: 200 message: { progressId: 1234 } 

and then allow the Lambda Function to continue (and periodically update the "processId" somewhere available to the client. The problem is that if you call context.succeed() , context.fail() or context.done() , which, apparently, the lambda functions are stopping from further execution, and yet this is the only way I know to flush the stdout buffer back to the API gateway.

This led me to a second approach, which I have not yet tried to solve (and for simplicity I would like to avoid), which includes an API gateway that calls the Responder function lambda, which then works asynchronously with Microservice and then immediately responds to the gateway API

I tried to illustrate these two parameters in the sketch format below. I would like to hear how someone was able to solve this problem.

Answer 1

Gateway APIs currently require AWMS Lambda integration to be synchronous. If you want an asynchronous call to your Lambda function, you have 2 options:

• Call Lambda asynchronously, either with AWS integration invoking InvokeAsync on Lambda, or using an intermediate service such as SNS or Kinesis to start the Lambda function.

• You are diagram # 2, using a Lambda synchronous call to initiate an asynchronous call.

Answer 2

As of April 2016, you can create asynchronous Lambda execution through an API gateway using AWS Service Proxy. See http://docs.aws.amazon.com/apigateway/latest/developerguide/integrating-api-with-aws-services-lambda.html

Answer 3

You can send an X-Amz-Invocation-Type header, it supports asynchronous calls using the Event value

You can request asynchronous execution by specifying the event as InvocationType

http://docs.aws.amazon.com/lambda/latest/dg/API_Invoke.html#API_Invoke_RequestSyntax

In addition, if you cannot send it through your microservice, you can configure this header for default transmission using the Execute method → Integration request → HTTP headers in the API gateway resource

This worked for me in the micro-service -> API Gateway -> Lambda script, as indicated in the question.