Building a Secure and Scalable Serverless Application on AWS with AWS CLI

Serverless architecture on AWS provides a highly scalable, cost-efficient way to build applications without worrying about the underlying infrastructure. In this blog, we’ll guide you through creating a secure and scalable serverless application on AWS using AWS CLI commands.

etting Up the AWS CLI

To interact with AWS services, you’ll need the AWS CLI installed and configured on your system.

1. Install AWS CLI:

pip install awscli

Configure AWS CLI:

aws configure

You’ll be prompted to enter your AWS Access Key, Secret Key, region, and output format.

3. Designing and Deploying a Serverless Application

Architecture Overview

We’ll build a simple serverless web application using AWS Lambda, API Gateway, DynamoDB, and S3.

Creating an S3 Bucket

Store static content like HTML, CSS, and JavaScript files in S3.

aws s3 mb s3://my-serverless-app-bucket

Upload files:

aws s3 cp index.html s3://my-serverless-app-bucket

Creating a DynamoDB Table

Store application data in DynamoDB.

aws dynamodb create-table \
    --table-name Users \
    --attribute-definitions AttributeName=UserID,AttributeType=S \
    --key-schema AttributeName=UserID,KeyType=HASH \
    --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5

Deploying a Lambda Function

Create a Lambda function that handles backend logic.

1. Create a deployment package (ZIP) with your code.

zip function.zip index.js

Create the Lambda function:

aws lambda create-function \
    --function-name MyServerlessFunction \
    --runtime nodejs14.x \
    --role arn:aws:iam::123456789012:role/lambda-ex \
    --handler index.handler \
    --zip-file fileb://function.zip

Setting Up API Gateway

Create an API to expose the Lambda function.

aws apigateway create-rest-api \
    --name 'MyServerlessAPI' \
    --description 'API for my serverless app'

Deploying the Application

Now, deploy the API using AWS CLI.

1. Create a deployment stage:

aws apigateway create-deployment \
    --rest-api-id 1234567890 \
    --stage-name prod

1. Test your API by invoking the endpoint.

curl https://{api-id}.execute-api.{region}.amazonaws.com/prod

Securing the Serverless Application

IAM Roles and Policies

Ensure your Lambda function has the appropriate permissions by attaching a policy to its role.

aws iam attach-role-policy \
    --role-name lambda-ex \
    --policy-arn arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole

Encrypting DynamoDB Data

Enable server-side encryption for your DynamoDB table.

aws dynamodb update-table \
    --table-name Users \
    --sse-specification Enabled=true

Monitoring and Logging

Use AWS CloudWatch for monitoring your Lambda function.

Setting Up CloudWatch Logs

Ensure your Lambda function is logging correctly.

aws logs describe-log-streams --log-group-name /aws/lambda/MyServerlessFunction

Setting Up CloudWatch Alarms

Create an alarm to monitor the invocation errors.

aws cloudwatch put-metric-alarm \
    --alarm-name LambdaErrorAlarm \
    --metric-name Errors \
    --namespace AWS/Lambda \
    --statistic Sum \
    --period 300 \
    --threshold 1 \
    --comparison-operator GreaterThanOrEqualToThreshold \
    --dimensions Name=FunctionName,Value=MyServerlessFunction \
    --evaluation-periods 1 \
    --alarm-actions arn:aws:sns:us-east-1:123456789012:NotifyMe

Regards
osama