AWS Compute Blog
Hands-Free Slack: AWS Lambda meets Amazon Echo
Tim Wagner, AWS Lambda
Amazon Echo is voice-based home automation. With it, you can listen to music, check the weather, or search the web…just by using your voice. And just like mobile phones and tablets, lots of exciting apps are going to be written for this new platform, using the Alexa Skills Kit (ASK) and AWS Lambda. Together, they offer a completely managed platform for voice recognition and cloud compute.
To demonstrate how easy it is to add completely new experiences to Echo (or any Alexa-powered device), I modified the Alexa “color” demo skill that’s built into the Lambda console to allow me to post messages to a Slack channel using my voice. With a command like, “Alexa, tell Slack to send, ‘The demo is ready!'”, I can send a Slack message hands-free. The following
video illustrates this in action.
Here’s the Alexa “intent schema” that I used:
You’ll also need to enable incoming webhooks (requests) in your Slack channel:
As mentioned in the video, the code is a trivial modification of the “MyColor” skill; I changed the color parameter to a message, and added an HTTP request to Slack at the point where the message is created. If you try this yourself, you’ll have to replace the http “path” option with your own Slack token to get it to work. Finally, testing your code (and Slack integration) from the Lambda console is super useful, but you’ll need to replace the “Color” section in the Alexa sample event (Alexa Event – MyColorIs) with a “Message” equivalent to get it to work with the code below.
var https = require('https');
var options = {
host: 'hooks.slack.com',
port: 443,
path: '/services/[put your own Slack access token here]',
method: 'POST'
};
/**
* This sample shows how to create a simple Lambda function for handling speechlet requests.
*/
// Route the incoming request based on type (LaunchRequest, IntentRequest,
// etc.) The JSON body of the request is provided in the event parameter.
exports.handler = function (event, context) {
try {
console.log("event.session.application=" + event.session.application.applicationId);
/**
* Uncomment this if statement and replace application.id with yours
* to prevent other voice applications from using this function.
*/
/*
if (event.session.application.id !== "amzn1.echo-sdk-ams.app.[your own app id goes here]") {
context.fail("Invalid Application ID");
}
*/
if (event.session.new) {
onSessionStarted({requestId: event.request.requestId}, event.session);
}
if (event.request.type === "LaunchRequest") {
onLaunch(event.request,
event.session,
function callback(sessionAttributes, speechletResponse) {
context.succeed(buildResponse(sessionAttributes, speechletResponse));
});
} else if (event.request.type === "IntentRequest") {
onIntent(event.request,
event.session,
function callback(sessionAttributes, speechletResponse) {
context.succeed(buildResponse(sessionAttributes, speechletResponse));
});
} else if (event.request.type === "SessionEndedRequest") {
onSessionEnded(event.request, event.session);
context.succeed();
}
} catch (e) {
context.fail("Exception: " + e);
}
};
/**
* Called when the session starts.
*/
function onSessionStarted(sessionStartedRequest, session) {
console.log("onSessionStarted requestId=" + sessionStartedRequest.requestId
+ ", sessionId=" + session.sessionId);
}
/**
* Called when the user launches the app without specifying what they want.
*/
function onLaunch(launchRequest, session, callback) {
console.log("onLaunch requestId=" + launchRequest.requestId
+ ", sessionId=" + session.sessionId);
getWelcomeResponse(callback);
}
/**
* Called when the user specifies an intent for this application.
*/
function onIntent(intentRequest, session, callback) {
console.log("onIntent requestId=" + intentRequest.requestId
+ ", sessionId=" + session.sessionId);
var intent = intentRequest.intent;
var intentName = intentRequest.intent.name;
if ("MyMessageIntent" === intentName) {
console.log("MyMessageIntent");
setMessageInSession(intent, session, callback);
} else if ("WhatsMyMessageIntent" === intentName) {
console.log("WhatsMyMessageIntent");
getMessageFromSession(intent, session, callback);
} else {
console.log("Unknown intent");
throw "Invalid intent";
}
}
/**
* Called when the user ends the session.
* Is not called when the app returns shouldEndSession=true.
*/
function onSessionEnded(sessionEndedRequest, session) {
console.log("onSessionEnded requestId=" + sessionEndedRequest.requestId
+ ", sessionId=" + session.sessionId);
}
/**
* Helpers that build all of the responses.
*/
function buildSpeechletResponse(title, output, repromptText, shouldEndSession) {
return {
outputSpeech: {
type: "PlainText",
text: output
},
card: {
type: "Simple",
title: "SessionSpeechlet - " + title,
content: "SessionSpeechlet - " + output
},
reprompt: {
outputSpeech: {
type: "PlainText",
text: repromptText
}
},
shouldEndSession: shouldEndSession
}
}
function buildResponse(sessionAttributes, speechletResponse) {
return {
version: "1.0",
sessionAttributes: sessionAttributes,
response: speechletResponse
}
}
/**
* Functions that control the app's behavior.
*/
function getWelcomeResponse(callback) {
// If we wanted to initialize the session to have some attributes we could add those here.
var sessionAttributes = {};
var cardTitle = "Welcome";
var speechOutput = "Welcome to the Alexa and Lambda demo app, "
+ "You can give me a message to send to our team's Slack channel by saying, "
+ "my message is...";
// If the user either does not reply to the welcome message or says something that is not
// understood, they will be prompted again with this text.
var repromptText = "You can give me your message by saying, "
+ "my message is...";
var shouldEndSession = false;
callback(sessionAttributes,
buildSpeechletResponse(cardTitle, speechOutput, repromptText, shouldEndSession));
}
/**
* Sets the message in the session and prepares the speech to reply to the user.
*/
function setMessageInSession(intent, session, callback) {
var cardTitle = intent.name;
var messageSlot = intent.slots.Message;
var repromptText = "";
var sessionAttributes = {};
var shouldEndSession = false;
var speechOutput = "";
if (messageSlot) {
message = messageSlot.value;
console.log("Message slot contains: " + message + ".");
sessionAttributes = createMessageAttributes(message);
speechOutput = "Your message has been sent. You can ask me to repeat it by saying, "
+ "what's my message?";
repromptText = "You can ask me to repeat your message by saying, what's my message?";
var req = https.request(options, function(res) {
res.setEncoding('utf8');
res.on('data', function (chunk) {
callback(sessionAttributes,
buildSpeechletResponse(cardTitle, speechOutput, repromptText, shouldEndSession));
});
});
req.on('error', function(e) {
console.log('problem with request: ' + e.message);
context.fail(e);
});
req.write('{"channel": "#aws-lambda", "username": "webhookbot", "text": "[via Alexa]: ' + message + '", "icon_emoji": ":ghost:"}');
req.end();
} else {
speechOutput = "I didn't hear your message clearly, please try again";
repromptText = "I didn't hear your message clearly, you can give me your "
+ "message by saying, my message is...";
callback(sessionAttributes,
buildSpeechletResponse(cardTitle, speechOutput, repromptText, shouldEndSession));
}
}
function createMessageAttributes(message) {
return {
message: message
};
}
function getMessageFromSession(intent, session, callback) {
var cardTitle = intent.name;
var message;
var repromptText = null;
var sessionAttributes = {};
var shouldEndSession = false;
var speechOutput = "";
if(session.attributes) {
message = session.attributes.message;
}
if(message) {
speechOutput = "Your message is " + message + ", goodbye";
shouldEndSession = true;
}
else {
speechOutput = "I didn't hear your message clearly. As an example, you can say, My message is 'hello, team!'";
}
// Setting repromptText to null signifies that we do not want to reprompt the user.
// If the user does not respond or says something that is not understood, the app session
// closes.
callback(sessionAttributes,
buildSpeechletResponse(intent.name, speechOutput, repromptText, shouldEndSession));
}
Alexa tell Slack to send, “Thanks for reading and happy Lambda coding!”