How to use unmarshal events to AWS defined types in lambda container image for go1.x with provided as base

Question

I use API Gatway to trigger Lambda with proxy integration

I build a lambda container image for Golang from public.ecr.aws/lambda/provided:al2 because of depedency that cannot be installed in public.ecr.aws/lambda/go:latest.

PFB for my Docerfile content

FROM public.ecr.aws/lambda/provided:al2
COPY ./config/yumrepo/dep1.repo /etc/yum.repos.d/dep1.repo
COPY ./config/yumrepo/dep2.repo /etc/yum.repos.d/dep2.repo

RUN yum install -y dep1 dep2

COPY --from=build /main /var/runtime/bootstrap # If I dont copy to bootstrap the lambda is not starting up

CMD [ "handler" ]

The problem I am facing is that the events are in marshalled state. If I make an api call to the lambda the intended function, which expects it as a events.APIGatewayProxyRequest throws error since the input is of type map[string]interface{}.

My guess is that this is someting to do with runtime interface clients and bootstrap. I got the following reference from AWS Lambda guide for the same

AWS does not provide a separate runtime interface client for Go. The aws-lambda-go/lambda package includes an implementation of the runtime interface.

The above image get build and with the following code made the API work.

func (h *Handler) HandleRequest(ctx context.Context, request interface{}) (interface{}, error) {
    requestMap := request.(map[string]interface{})
    _, ok := getMapValue(requestMap, "headers")
    if ok {
        httpMethod, _ := getStringValue(requestMap, "httpMethod")
        resource, _ := getStringValue(requestMap, "resource")
        body, _ := getStringValue(requestMap, "body")
        requestObj := events.APIGatewayProxyRequest{
            Body:            body,
            IsBase64Encoded: false,
            Resource:        resource,
            HTTPMethod:      httpMethod,
        }
        return h.HandleAPIRequest(ctx, requestObj)
    }
    return nil, fmt.Errorf("unknown request type")
}

Is this the proper way to build the image and how to recive event in AWS defined types in my code?

Answer 1

Found the issue

since the handler function expectes interface the request is passed as map[string]interface{} after I changed the type of the request parameter to events.APIGatewayProxyRequest my code automatically started to receive in this type.