CDK script to deploy the static site to S3 and CloudFront

Overview

The project is a companion to the tutorial on my blog.

We will implement infrastructure for the static website with the following features.

• Host website on Amazon S3 private bucket.
• Use Amazon CloudFront CDN in front of the website to cache the site data and send security headers.
• Support both HTTPS and HTTP protocols with an automatic redirect from HTTP to HTTPS.
• Use AWS CDK to define and deploy the infrastructure.
• Automatically update the infrastructure and deploy the website with GitHub actions.

Prerequisites

We deploy the website in the Amazon AWS public cloud. If you want to follow the tutorial, you might want to create an AWS account. The getting started guide or the CDK Workshop prerequisites section contains everything you need to know.

Please find below a checklist with prerequisites to perform the tutorial.

• Create an IAM user for the AWS account.
• Set up AWS CLI and register the user's credentials with it.
• Install NodeJs on your computer. I recommend the latest stable version (LTS), which is now 16.17.0.
• Register DNS zone for website's domain in the AWS Route 53.

CDK application layout

• .github contains workflow to deploy the stack with GitHub actions.
• .husky contains a GitHook definition to check code formatting on commit.
• cdk.out is the folder where the CDK application keeps its generated code.
• dist is the out directory for the TypeScript compiler, and the CDK application takes scripts from there.
• src/main.ts is the entry point for the CDK application. Please keep in mind that we compile the TypeScript code first. Then we run the JavaScript code from the dist folder.
• cdk.json tells the toolkit how to run the application. In our case, it instructs the toolkit to compile the application and run the JavaScript code.

Basic commands to work with the CDK application

• npm run build compile TypeScript from the src folder to JavaScript in the dist folder.
• npx cdk diff compare deployed stack with the current state.
• npx cdk deploy --all deploy all three stack sto the default AWS account and region from the default profile.
• npm run clean removes all compiled JavaScript code and generated CDK templates.
• npm run format fixes source code formatting and checks the code for the coding standard.
• npm run test does not do any test but only validates code formatting.

Retrieving AWS credentials in GitHub actions

We need AWS credentials to run the CDK deployment in GitHub actions. But we do not want to keep the API credentials in the repository secrets because this would require updating the credentials manually. So instead, the best approach would be to set up IAM permissions, allowing actions in the repository to deploy. Then, we decide which GitHub project can do what by changing the IAM roles.

Luckily, we can configure the OpenID connection in our AWS account for GitHub. So GitHub can obtain temporary AWS credentials by using this connection. And we can decide what role the action can assume. Please check the manual for a detailed explanation.

We should add the GitHub OIDC provider only once to the AWS account and link different roles to it. To achieve this, I extracted the construct for the OpenID connection provider to the dedicated stack. Then, we deploy it with the following command.

npx cdk deploy GithubConnectionStack

We should create a role for the GitHub actions by manually deploying the site stack.

npx cdk deploy SiteStack

Next time we push to the main branch, the GitHub action assumes the role to run the deployment.

Automatic CDK deployment from the GitHub actions

The deployment feels like bliss when we have the AWS credentials in place. Please check the code of the action below.

      - name: Retrieve AWS credentials
        uses: aws-actions/configure-aws-credentials@v1
        with:
          role-to-assume: ${{ secrets.AWS_ROLE_ARN }}
          aws-region: ${{ secrets.AWS_REGION }}

      - name: Deploy site stack
        run: npx cdk deploy --require-approval never SiteStack

We retrieve temporary AWS credentials for the given role. And then, we run the CDK deployment as we do on the local computer.

We now have an empty CDK project with CI we can use as a starting point in the future. Let's add static site resources to it.