How do I make Lex + Lambda ask the user are they ready for fulfillment?

Question

I've got a basic bot set up that asks the user for some input in format such as:

User input: I need information on {policy}

Then a lambda function is executed that validates the policy entered using some basic regex. This all works perfectly and as expected.

Then, it returns the dialogAction to lex, which I have set up as follows:

return {"dialogAction": {
        "type": "ConfirmIntent",
        "fulfillmentState": "ReadyForFulfillment",
        "message": {
            "contentType": "PlainText",
            "content": "Your policy " + policy + " is " + retStr (this just says valid or invalid) + " input."
        }
    }}

Ideally, when tested, I want this to validate the user input with the regex, then the bot to essentially do the ReadyForFulfillment message, but that doesn't work. Instead it crashes and I get:

An error has occurred: The server encountered an error processing the Lambda response

I have logging set up, which I used for other errors but when it errors out for this stuff, it doesn't produce an error in the CloudWatch logs.

I can change fulfillmentState to 'Fulfilled' and type to 'Close' and this will run perfectly. But I want the 'ReadyForFulfillment' option.

Here is my full lambda function:

import json
import logging
import re

logger = logging.getLogger()
logger.setLevel(logging.DEBUG)

def dispatch(event):
    slots = event["currentIntent"]["slots"];
    policy = slots["policy"]

    if re.match(r"policy\.([\w]+\.)+[\w]+(?=[\s]|$)", policy):
        print("Valid input.")
        retStr = "valid"
    else:
        print("Invalid input.")
        retStr = "invalid"

    return {"dialogAction": {
        "type": "ConfirmIntent",
        "fulfillmentState": "ReadyForFulfillment",
        "message": {
            "contentType": "PlainText",
            "content": "Your policy " + policy + " is " + retStr + " input."
        }
    }}


def lambda_handler(event, context):
    
    logger.debug('event={}'.format(event))
    response = dispatch(event)
    logger.debug(response)
    return response

Answer 1

Have you tried the different dialogAction types?