带有Google Flex env的端点

There is bit of a confusion, wondering if somebody can help me with this.

Here is an example which is a year old and uses goapp with polymer and endpoint https://github.com/googlesamples/cloud-polymer-go

Here is a recent example using gcloud https://github.com/GoogleCloudPlatform/golang-samples/tree/master/appengine_flexible/endpoints

Both are different as google changed its approach.

As per second example, I am able to create endpoint functions which uses json for input and output. However there are 2 problems

1st. It is throwing error if I put functions in different file under same package. It works when I run go run .go. but then I dont understand how app.yaml come into picture. I think this url /_ah/spi/. should work

2nd. I am using postman app to check the request and response from endpoint. Is there a better way? I thought google does provide a platform to test endpoint.

Is there any example which implements examples similar to 1st one with new libraries?

looking forward for your help. Thanks.