API Gateway new (beta) http api - amazon-web-services

Question

I have created a sample HTTP API (which is currently in a beta release) using the API gateway. This API does not use any authentication and has a lambda as an integration. The route accepts any HTTP method and I have confirmed that the lambda has the proper API gateway permission. This permission was added when I created the API.
However, when I call the API I receive an HTTP status of 500 and a body of: {"message":"Internal Server Error"}.
This same lambda and API will work if I set it up as a REST API rather than an HTTP API.
Any ideas why this isn't working in the HTTP API?

Answer 1

I had a similar issue with Internal Server Error. I was using the new API Gateway HTTP API (beta) with a nodejs lambda integration. The lambda on its own worked and the REST API worked fine, like you noted.
The 2 issues that cost me 8 hours:
I had to add an async prefix to the handler or use a callback, but I couldn't just return a response without async. See https://docs.aws.amazon.com/lambda/latest/dg/nodejs-prog-model-handler.html
The response structure has to be correct, see this page: https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-create-api-as-simple-proxy-for-lambda.html#api-gateway-proxy-integration-create-lambda-backend, scroll to the example function code and you'll see this:
// The output from a Lambda proxy integration must be
// in the following JSON object. The 'headers' property
// is for custom response headers in addition to standard
// ones. The 'body' property must be a JSON string. For
// base64-encoded payload, you must also set the 'isBase64Encoded'
// property to 'true'.
So my function ended up looking like this, note the async and the proper response structure:
exports.handler = async function(event, context) {
const response = {
statusCode: 200,
body: JSON.stringify('Hello from Lambda!')
};
return response;
}