app.py

import json

def callback(event, context):
    body = {
        "message": "Go Serverless v1.0! Your function executed successfully!",
        "input": event
    }

    response = {
        "statusCode": 200,
        "body": json.dumps(body)
    }

    return response

serverless.yml

service: oauth2cb

provider:
  name: aws
  runtime: python3.6
  stage: prod
  region: us-east-1

functions:
  callback:
    handler: app.callback
    events:
      - http:
          path: oauth2/callback
          method: get