kunlaboratorium-aws-lambda-text2speech

This repository contains a number of sequential exercises that leverage AWS to convert text to speech. You will learn about AWS services like S3, Lambda and Polly. You will also touch AWS concepts like roles and events.

When you have finished all exercises, you will have built a system that:

• picks up a textfile in an S3 bucket
• converts the text to speech
• saves the speech as an MP3-file on S3

Exercise 1 - Explore the AWS console

An AWS account has been created for you and will be provided by the Kunlaboratorium hosts.

Go to AWS console and login.

AWS offers a lot of services, grouped into topics like Storage, Compute, ... Take a look around and see if you can find the EC2 service.

Exercise 2 - Explore Polly

• Open the console and locate the Polly service
• Click on the text-to-speech section
• Fill in some text, choose a language and region, choose a voice
• Now you can listen to the speech or download an MP3 file

Exercise 3 - Create a text file in S3

• Open the console and go to the S3 storage service.
• Create a bucket.
• Create a folder (e.g. text)
• Inside the folder, upload a .txt file containing some text.

Source: https://docs.aws.amazon.com/AmazonS3/latest/user-guide/what-is-s3.html

Exercise 4 - Build the project

• Let's first review the codebase together...
• Run ./gradlew clean build to build our project
• A zipfile containing our code is now created in build/distributions
• Later, this has to be uploaded to AWS Lambda...

Exercise 5 - Create a Lambda function

• Open the console and go to the Lambda service.
• Create a function from scratch for the Java 8 runtime
• In the Handler field, fill in be.kunlabora.kunlaboratorium.aws_text_to_speech.MyTextToSpeechFunction::handleRequest
• Upload the zipfile to Lambda and click save
• Create an test event using the Amazon S3 put template
• In the test event, fill in the aws region, bucket name and object key, according to the text file you created earlier
• Save the test event and execute your Lambda by clicking Test
• Your Lambda should fail with an Access denied error...

Exercise 6 - Roles

Why does your Lambda fail with an Access Denied error? Why can't one AWS service just call another one?

• A role has been created automatically for your Lambda function
• Open the role in AWS IAM and attach the AmazonPollyReadOnlyAccess and AmazonS3FullAccess policies
• Try your Lambda again...

Exercise 7 - S3 event

We want our Lambda to be triggered automatically whenever we upload a new text file to our bucket

• Upload a new file to your bucket; is your Lambda triggered?
• In the S3 console, go to your bucket and locate Events in the properties section
• Create a bucket event for .txt files that are created in your bucket
• See if you can wire the event to your lambda function
• Now try to upload a new file again...

Congratulations!