Home Assistant Proxy for Amazon Alexa

A lightweight Lambda function for proxying requests from an Amazon Alexa skill to Home Assistant.

Requirements

• Amazon Developer account
• AWS Account
• Public Home Assistant URL (must be secured with TLS)
• Home Assistant Alexa Smart Home component configuration

Also see https://developer.amazon.com/de/docs/smarthome/understand-the-smart-home-skill-api.html and https://www.home-assistant.io/components/alexa/#smart-home

Configuration

• HASS_URL: URL to Home Assistant (e.g. https://your-home-assistant-url.io)
• BEARER_TOKEN: Long lived acces token (optional)
• VERIFY_SSL: Has to be false for self signed certificates. (default: true)

Setup

1. Create a new Amazon Alexa skill on https://developer.amazon.com/alexa/console/ask/create-new-skill

   1. Enter a Skill name, e.g. "Home Assistant"
   2. Set your Default language
   3. Select Smart Home as model
   4. Click Create skill

2. Create an AWS Lambda function on https://console.aws.amazon.com/lambda/home#/create in your AWS region

   1. Select Author from scratch
   2. Enter a function name, e.g. "home_assistant_proxy"
   3. Select Python 3.8 as runtime
   4. Select a lambda role, e.g. "lambda_basic_execution"
   5. Click Create function

3. Configure AWS Lambda function

   1. Copy and paste the code from hass_proxy.py into the function code editor and click the "Deploy" button
   2. Add a HASS_URL environment variable which is set to the public base URL of your Home Assistant, e.g. "https://your-home-assistant-url.io"
   3. (optional) If you are using a self signed certificate for your Home Assistant, set the VERIFY_SSL environment variable to false
   4. Add Alexa Smart Home trigger
      1. Enter the Skill ID from your Alex skill in the Application ID field
      2. Select Enable trigger
      3. Click Add

4. Configure Amazon Alexa Skill

   1. Enter the ARN of the AWS Lambda function
   2. Click Save
   3. Click Setup Account Linking
      1. In Authorization URI enter the authorize URI of your Home Assistant, e.g. "https://your-home-assistant-url.io/auth/authorize"
      2. In Access Token URI enter the access token URI of your Home Assistant, e.g. "https://your-home-assistant-url.io/auth/token"
      3. Enter a redirect URL of Amazon Alexa as Client ID, e.g. "https://layla.amazon.com" (see Redirect URLs)
      4. Enter anything in Client Secret (is not used by Home Assistant)
      5. Select "HTTP Basic" as Client Authentication Scheme
      6. Add any Scope, e.g. "API" (is not used by Home Assistant)
      7. Click Save

5. Activate your Skill in the Amazon Alexa app or in the web interface

6. Discover devices

Differences to Haaska

• Makes use of Home Assistant's Authentication API. There is no need to configure an oAuth provider or to create a long lived token.
• No dependencies to additional Python packages. It is not necessary to create a deployment package and upload it to AWS Lambda. Just copy the code from the hass_proxy.py file and paste into the AWS Lambda function editor.
• No config files. All configuration is done using environment variables.