AWS Lambda Serverless Reference Architecture: Web Applications

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Fork of the original version of lambda-refarch-webapp as it was at commit ceda53fc23, which now resides at lambda-refarch-voteapp.

This fork has the following changes:

• uses voting via the web page rather than via SMS
• uses the Python runtime for all Lambda functions
• uses YAML for the CloudFormation templates
• uses the AWS Serverless Application Model
• uses CodePipeline with CodeBuild to automatically package and then deploy the infrastructure with CloudFormation after every push to the repo
• uses a Lambda-backed custom resource to automatically set appropriate values in refresh.js (AWS region, Cognito Identity Pool id, API Gateway endpoint, DynamoDB table name)
• the voting topic has been changed to something much more likely to incite a flame war ;)

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Serverless Reference Architecture illustrating how to build dynamic web applications using AWS Lambda and Amazon API Gateway to authenticate and process API requests.

By combining AWS Lambda with other AWS services, developers can build powerful web applications that automatically scale up and down and run in a highly available configuration across multiple data centers—with zero administrative effort required for scalability, backups, or multi–data center redundancy.

This example looks at using AWS Lambda and Amazon API Gateway to build a dynamic voting application, which receives votes via web requests, aggregates the totals into Amazon DynamoDB, and uses Amazon Simple Storage Service (Amazon S3) to display the results in real time.

A similar architecture to that described in this diagram can be created with AWS CloudFormation templates, one of which uses the AWS Serverless Application Model.

The base template does the following:

• Creates an S3 bucket to hold your web app's static files
• Creates a Route 53 resource record set to point your chosen subdomain to the S3 website endpoint
• Creates an S3 bucket to hold Lambda packages for deployment
• Creates a CodePipeline pipeline to pull this repository from your GitHub, package the Lambda functions etc using CodeBuild, and deploy the following template using CloudFormation

The serverless application template does the following:

• Creates a DynamoDB table to store votes
• Creates a DynamoDB table to aggregate vote totals
• Creates a Lambda function that allows your application to receive votes
• Creates an API Gateway endpoint for votes to be proxied to this Lambda function
• Creates a Lambda function that aggregates the votes from a DynamoDB Stream
• Creates a Cognito Identity Pool and configures it with appropriate IAM Roles
• Creates a Lambda-backed custom resource that automatically sets appropriate values in refresh.js (AWS region, Cognito Identity Pool id, API Gateway endpoint, DynamoDB table name)

Dynamic Dashboard

The services and resources configured by the AWS CloudFormation templates can be tested with the HTML page index.html, which relies on the HTML, JavaScript, and CSS files found in this repo.

Instructions

This example demonstrates receiving votes via a web page and displaying the vote totals.

Step 1 - Fork this GitHub repository

Step 2 - Create a GitHub personal access token with full repo scope for CodePipeline to use.

Step 3 – Create an AWS CloudFormation stack using the base.yaml template in the templates/ directory. You'll need to enter:

• The name of an existing Route 53 hosted zone (e.g. example.com)
• The id of that hosted zone
• The subdomain that you want to use (e.g. for vote.example.com just enter the hostname: 'vote')
• The GitHub personal access token you created in the previous step
• Your GitHub username (so the fork of this repo can be specified)
• The repository name if you have changed it, otherwise leave as default

Congratulations! After a few minutes, the pipeline will have completed (check the CodePipeline console for status), and you should now have a working example of the reference architecture. Now go to the site (e.g. at http://vote.example.com) to see it in action.

You are able to receive votes in real time, tune your DynamoDB table to handle various levels of incoming traffic, and watch your results change on your dashboard in real time!

Any changes that you make to the application or infrastructure will be automatically reflected when you push the changes back to GitHub. (base.yaml is an exception - any changes to this template need to be applied directly to the CloudFormation stack)

Cleanup

To remove all automatically created resources, delete the AWS CloudFormation stacks: *-serverless-application first, then the base stack.

Note: Deletion of the S3 buckets will fail unless all files in the bucket are removed before the base stack is deleted.

License

This reference architecture sample is licensed under Apache 2.0.