How to pass & accept the http request parameters in server less framework of AWS Lambda?

I am not able to access the http request-parameters passed as a json object in my lambda function. Where is it supposed to be configured? Is it in the template of the serverless.yml?

        template:
          application/json: '#set($allParams = $input.params()) {
                                "id"   : $input.json("id"),
                                "name" : $input.json("name"),

I am running this example as -curl -X GET -u user@xyz.com:password -H "Content-Type: application/json" -d ' { "id": "1", "name": "Tom" }' http://localhost:port/path_in_events_path

I see that there are examples which says $input.json('$') what does the '$' signify? What are the other members of input? I see there are:

1. $input.json()
2. $input.params()

via Sumit Kumar Ghosh