AWS Lambda function for forwarding Alexa Intent requests to Home Assistant

example_hass_alexa_intents_lambda_function.py

# -*- coding: utf-8 -*-
import os
import json
import logging
import urllib3

_debug = bool(os.environ.get('DEBUG'))

_logger = logging.getLogger('HomeAssistant-Intents')
_logger.setLevel(logging.DEBUG if _debug else logging.INFO)


def lambda_handler(event, context):
    """Handle incoming Alexa directive."""

    _logger.debug('Event: %s', event)

    base_url = os.environ.get('BASE_URL')
    assert base_url is not None, 'Please set BASE_URL environment variable'

    try:
        token = event.get('session', {}).get('user', {}).get('accessToken')
    except AttributeError:
        token = None

    if token is None and _debug:
        token = os.environ.get('LONG_LIVED_ACCESS_TOKEN')

    assert token, 'Could not get access token'

    verify_ssl = not bool(os.environ.get('NOT_VERIFY_SSL'))

    http = urllib3.PoolManager(
        cert_reqs='CERT_REQUIRED' if verify_ssl else 'CERT_NONE',
        timeout=urllib3.Timeout(connect=2.0, read=10.0)
    )

    response = http.request(
        'POST',
        '{}/api/alexa'.format(base_url),
        headers={
            'Authorization': 'Bearer {}'.format(token),
            'Content-Type': 'application/json',
        },
        body=json.dumps(event).encode('utf-8'),
    )
    if response.status >= 400:
        return {
            'event': {
                'payload': {
                    'type': 'INVALID_AUTHORIZATION_CREDENTIAL'
                    if response.status in (401, 403) else 'INTERNAL_ERROR',
                    'message': response.data.decode("utf-8"),
                }
            }
        }
    return json.loads(response.data.decode('utf-8'))

Hello.

I followed this guide: https://github.com/home-assistant/home-assistant.io/blob/current/source/_integrations/alexa.intent.markdown

But I only could get success on linking the account if I remove the 8123 port on all home assistant links, in lambda function and alexa app, and port forward on my router from external 443 to 8123. Otherwise, the lambda function returns:

[ERROR] AssertionError: Could not get access token
Traceback (most recent call last):
  File "/var/task/lambda_function.py", line 29, in lambda_handler
    assert token, 'Could not get access token'

Could you check the code or the guide for this, please?

The guide and docs assume you've got an externally accessible Home Assistant instance, see the third requirement:

The Alexa Custom Skill API also needs your Home Assistant instance can be accessed from Internet. We strongly suggest you host HTTPS server and use validation certificate. Read more on our blog about how to set up encryption for Home Assistant. When running Hass.io using the Duck DNS add-on is the easiest method.

Yes, it's accessible from the internet but it only works if the external port is 443, instead of the 8123 proposed in the tutorial.

Yea, that's an Amazon requirement:

Note that the account linking URL must be a HTTPS URL on port 443, with a certificate from an Amazon approved CA authority (https://ccadb-public.secure.force.com/mozilla/IncludedCACertificateReport).
https://forums.developer.amazon.com/articles/38610/alexa-debugging-account-linking.html

It's actually noted on the Smart Home docs but not on the Custom Intent ones. I've submitted a pull request to clarify that on both.

The NOT_VERIFY_SSL env var doesn't seem to work at all (and I expect the same is true for debug)
It doesn't matter how I set the environment variable it doesn't change the SSL behavior.

My belief based on some googling is that environment variables are NOT booleans as such all this code tests for is the presence of envvar.
But i am not sure and too code illiterate to know how to fix (i tried several of the suggestions in the link)

    verify_ssl = not bool(os.environ.get('NOT_VERIFY_SSL'))

    http = urllib3.PoolManager(
        cert_reqs='CERT_REQUIRED' if verify_ssl else 'CERT_NONE',
        timeout=urllib3.Timeout(connect=2.0, read=10.0)

i worked around this by hard coding it to certs required

#    verify_ssl = not bool(os.environ.get('NOT_VERIFY_SSL'))

    http = urllib3.PoolManager(
        cert_reqs='CERT_REQUIRED',  #if verify_ssl else 'CERT_NONE',
        timeout=urllib3.Timeout(connect=2.0, read=10.0)

---edit-- oh i see
all the code does is detect if the var is present, it doesn't care what it is set to to.
This means the docs at here are wrong.

NOT_VERIFY_SSL (optional): set to True to ignore the SSL issue, if you don’t have a valid SSL certificate or you are using self-signed certificate.
DEBUG (optional): set to True to log debugging messages.

one needs to REMOVE NOT_VERIFY_SSL to turn on SSL checking and add it to turn it off, what ever it is set to is irrelevant (i couldn't for the life of me figure out why when i set to false it did nothing, lol)