Code samples related to Building Better Bots published on the AI Blog

CoffeeBot is a transactional chat bot that can help one order a mocha (relies on AWS Mobile Hub and Android).

Consider this conversation:

User: May I have a mocha?

CoffeeBot: What size? small, medium, large?

User: small

CoffeeBot: Would you like that iced or hot?

User: hot

CoffeeBot: You'd like me to order a small mocha. Is that right?

User: Make it a large mocha

CoffeeBot: You'd like me to order a large mocha. Is that right?

User: yeah

CoffeeBot: Great! Your mocha will be available for pickup soon. Thanks for using CoffeeBot!

Let's build this voice bot, an Android App that talks to you using Amazon Polly and Amazon Lex. You'll need the following in addition to your AWS account:

• Android development environment (download)
• To test voice (you can use the simulator for text)
  • An Android device
  • A USB cable for USB debugging (more info for Amazon Fire tablets)

First, we'll create the Lex bot. Then, we'll add some Lambda Functions to bring it to life. Finally, we'll put it all together with Mobile Hub and the Lex Android SDK.

Create two IAM roles as described below. For more information, you can use the instructions provided in the Lex documentation.

1.CoffeeBot_app_role - a Service role so Lex can invoke Lambda on your behalf with this custom inline policy (it's easy to start with Lambda and then swap it out with Lex as shown below)

{
	"Version": "2012-10-17",
	"Statement": [
		{
			"Action": [
				"lambda:InvokeFunction",
				"polly:SynthesizeSpeech"
			],
			"Effect": "Allow",
			"Resource": "*"
		}
	]
}

This role also needs to trust the Amazon Lex service principal (lex.amazonaws.com).

{
	"Version": "2012-10-17",
	"Statement": [
		{
			"Effect": "Allow",
			"Principal": {
				"Service": "lex.amazonaws.com"
			},
			"Action": "sts:AssumeRole"
		}
	]
}

2.CoffeeBot_lambda_role - a Lambda Service role so the Lambda fulfillment function can assume the role and write logs (start with this custom inline policy)

{
	"Version": "2012-10-17",
	"Statement": [
		{
			"Effect": "Allow",
			"Action": [
				"logs:CreateLogGroup",
				"logs:CreateLogStream",
				"logs:PutLogEvents"
			],
			"Resource": [
				"*"
			]
		}
	]
}

1. From the Amazon Lex console, create a Custom bot with these settings (you can see these in the "Settings" tab later)

• Bot name: CoffeeBot
• Output voice: Salli
• Session timeout: 10 min
• IAM role: CoffeeBot_app_role

1. Review the Error handling settings

• Prompts: (one prompt) Sorry, can you please repeat that?
• Maximum number of retries: 5
• Hang-up phrase: (one phrase) Sorry, I could not understand. Goodbye.

1. Add the following Slot types so they show up on the left (remember to Save as you go along).

From the left, add a new Intent called cafeOrderBeverageIntent with the following settings and click "Save" to save the Intent

1. Options (leave options unchecked)
2. Fulfillment: choose "Return parameters to client" for now
3. Confirmation prompt: You'd like me to order a {BeverageSize} {BeverageType}. Is that right? to confirm and Okay. Nothing to order this time. See you next time! to cancel.
4. Sample Utterances

I would like a {BeverageSize} {BeverageType}
Can I get a {BeverageType}
May I have a {BeverageSize} {Creamer} {BeverageStrength} {BeverageType}
Can I get a {BeverageSize} {BeverageTemp} {Creamer} {BeverageStrength} {BeverageType}
Let me get a {BeverageSize} {Creamer} {BeverageType}

5. Slots

Build the app and test some of the Utterances in the Test Bot dialog at the bottom right of the Lex Console. For example, if you say May I have a chai?, does Lex correctly map chai to the BeverageType slot?

1. Create the cafeOrderCoffee function by saving cafeOrderCoffee_lambda.js as a Node.js 4.3 function

• (No need to set up a trigger; you can accept default values for most of the configuration)
• Choose CoffeeBot_lambda_role as the IAM role
• Test (see cafeOrderCoffee_test.json)

1. From the Lex Console, select the CoffeeBot bot and choose Latest from the version drop down to make changes
2. Modify the cafeOrderBeverageIntent Intent to associate it with the new cafeOrderCoffee Lambda function; remember to click "Save"

• The Lambda function overrides the "Goodbye message" (so we don't configure it here)

1. Build the app
2. Test using Lex Console; do you see any responses when you ask May I have a mocha?

1. From the Mobile Hub console, create a new project called CoffeeBot.
2. Add the "Conversational Bots" feature to the project. When prompted, import CoffeeBot. Mobile Hub takes care of a number of important details behind the scenes. A new Amazon Cognito Federated Identity Pool is created for this new app along with roles so that the users can interact with Lex (using voice and text).
3. Source code for the new app is immediately available for download.
4. Follow the instructions in the READ_ME/index.html file to setup, compile, and run the app.