Event is empty in my lambda function when using Rest API

Question

So I have a lambda function that's the following:
def lambda_handler(event, context):
    http = urllib3.PoolManager()
    return {
        "statusCode": 200,
        "headers": {
            "Content-Type": "application/json"
        },
        "body": "{\"message\": \"Hello from Lambda!\"}",
        "test": event
    }

If I test run the event with some event JSON, it returns what I want. But...
when I test to run the lambda through my rest API I created I either get the error 502 when "Use Lambda Proxy integration" is enabled. Or when it's disabled event is always empty. I have tried to setup a link the following way:

https://something.execute-api.eu-north-1.amazonaws.com/test/test/{id}

Where you enter an {id} for example and I can catch it in the event. But how can I fix so event is an actual thing and actually getting any information?
If you feel like im missing some information that might be important just ask, I don't know what could be useful.

Answer

If you're using a non-proxy Lambda integration, you need to craft your payload using a model in the method request in API Gateway. You can see an example of how this works here [1]. If you're using a Lambda proxy integration type and you're getting a 502 error, this would often be a result of your function response being malformed and therefore API Gateway is unable to parse it. The response for a Lambda proxy integration must conform to the format that API Gateway is expecting in order for it to be successfully parsed. You can see the required format here [2]. If you're still having issues I'd recommend setting up execution logs for your API so that you can get more information on the cause of the failure.

Resources:

[1] Tutorial: Build an API Gateway REST API with Lambda non-proxy integration - Create an API with Lambda non-proxy integration - https://docs.aws.amazon.com/apigateway/latest/developerguide/getting-started-lambda-non-proxy-integration.html#getting-started-new-api
[2] Set up Lambda proxy integrations in API Gateway - Output format of a Lambda function for proxy integration - https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html#api-gateway-simple-proxy-for-lambda-output-format

Event is empty in my lambda function when using Rest API

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