Building-serverless-Text-to-Speech

Building Serverless Text - to - Speech application using Amazon Polly and Amazon Amplify

Creating a Serverless Project/Service

Install serverless framework by with npm and create a new nodejs project/service called backend.

npm install serverless -g

serverless create --template aws-nodejs --path backend

Now replace to serverless.yml file with following code, that creates a lambda function called “speak”.

Creating an S3 Bucket

We need an S3 bucket to store all the voice clips that are returned by AWS Polly. Use AWS console to create the bucket with a unique name. In my case, S3 bucket name is “my-talking-app”.

Create an IAM Role

The serverless framework creates two Lambda functions that interact with AWS Polly and AWS S3 services. In order to communicate with these services, our Lambda function must be assigned an IAM role that has permission to talk to S3 and Polly. So, create an IAM role with a preferred name i.e. “talking-app-role” with the following IAM policy.

{ "Version": "2012-10-17",

"Statement": [

    {
    
        "Sid": "VisualEditor0",
        
        "Effect": "Allow",
        
        "Action": [
        
            "polly:*",
            
            "s3:PutAccountPublicAccessBlock",
            
            "s3:GetAccountPublicAccessBlock",
            
            "s3:ListAllMyBuckets",
            
            "s3:HeadBucket"
        ],
        
        "Resource": "*"
    },
    {
        "Sid": "VisualEditor1",
        
        "Effect": "Allow",
        
        "Action": "s3:*",
        
        "Resource": [
            "arn:aws:s3:::my-talking-app",
            
            "arn:aws:s3:::my-talking-app/*"
            
        ]
    }
]

}

Copy the ARN of the IAM role and add it under the provider section of the serverless.yml file.

provider: name: aws

runtime: nodejs8.10

region: us-east-1

role: arn:aws:iam::885121665536: role/talking-app-role

“Speak” Lambda Function

Speak Lambda function does three main tasks.

Call AWS Polly synthesizeSpeech API and get the audio stream (mp3 format) for text that user entered

Save the above audio stream in the S3 bucket

Get a signed URL for the saved mp3 file in the S3 and send it back to the frontend application First of all, let’s install the required npm modules inside the backend folder.

npm install aws-sdk

npm install uuid

AWS Polly synthesizeSpeech API requires the text input and the voice id to convert the text into speech. Here, we use the voice of “Joanna” to speak the text that is passed from the frontend.

Now, deploy the backend API and the Lambda function

sls deploy

kaviya-sri123 / building-serverless-text-to-speech Goto Github PK