Mohamed Labouardy

@mlabouardy

Building an Alexa-Based GitHub Follower Counter

This post is part of “Alexa” series. I will walk you through how to build an Amazon Alexa Skill with Node.JS and Lambda to get numbers of followers & repositories in GitHub in real-time.

Note: all the code is available in my GitHub.

Amazon Echo will captures voice commands and send them to the Alexa Skill to convert them into structured text commands. A recognized command is sent to an AWS Lambda function that will call GitHub API to get response.

To get started, sign up to Amazon Developer Console, and create a new Alexa Skill:

The invocation name is what user will say to trigger the skill. In our case it will be “github“.

Click on “Next” to bring up the Interaction Model page, use the intent schema below:

Intents will map user’s voice command to services that our Alexa skill can address. For instance, here I defined an intent called GetGithubFollowerCount, which will line up with a portion of code in my Lambda funtion that I leverage in a bit.

The programming languages are defined as a Custom Slot Type, with the following possible values:

Go
Java
Python
C
C++
Javascript
HTML
Scala
Ocaml
NodeJS
Ruby
PHP
CSS
C#
Perl
Shell
Objective C

Now our intents are defined, we need to link them to a human request that will trigger this linkage. To do this multiple sentences (utterances) are listed to make the interaction as natural as possible.

GetGithubFollowerCount how many followers do I have
GetGithubFollowerCount current followers
GetGithubFollowerCount number of followers
GetGithubRepositoryCount how many repositories do I have
GetGithubRepositoryCount number of repositories
GetGithubRepositoryCount current repositories
GetGithubRepositoryCountByLanguage how many {Language} repositories
GetGithubRepositoryCountByLanguage number of {Language} repositories
GetGithubRepositoryCountByLanguage current {Language} repositories

Result:

Click on “Next” and you will move onto a page that allows us to use an ARN (Amazon Resource Name) to link to AWS Lambda.

Before that, let’s create our lambda function, login to AWS Management Console, then navigate to Lambda Dashboard and create a new function from scratch:

Select Alexa Skills Kit as trigger:

I wrote the Lambda functions in Node.JS, although that code isn’t actually that interesting so I won’t go into it in much detail.

This function is fired when there is an incoming request from Alexa. The function will:

  • Process the request
  • Call GitHub API
  • Send the response back to Alexa

Create a zip file consisting of the function above and any dependencies (node_modules). Then, specify the .zip file name as your deployment package at the time you create the Lambda function. Don’t forget to set your GitHub Username as an environment variable:

Back in the Alexa Skill we need to link our Lambda function as our endpoint for the Alexa Skill:

That’s it, let’s test it out using a Service Simulation by clicking on “Next“.

GetFollowerCount Intent :

GetRepositoryCount Intent:

GetGithubRepositoryCountByLanguage Intent:

You can see that the Lambda responds as expected !

Test it now with Amazon Echo, by saying “Alexa, ask GitHub for …” :

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