Set up with AWS CloudFront

For sites using AWS CloudFront, set up Same-Origin by creating a new origin, behavior, and Lambda@Edge function.

Step 1. Configure the origin

• In the CloudFront console, open your distribution and go to the Origins tab.
• Click Create origin.
• In the Origin domain field, enter your Wascer container domain (for example, sst.yoursite.com.br).
• Select HTTPS only as the protocol.
• Add a custom header: name X-From-Cdn, value cft-wascer.
• Confirm the origin creation.

Step 2. Configure the behavior

• Go to the Behaviors tab and create a new behavior.
• Set the Path pattern to /metrics/* (adjust it for your path).
• Select the origin created in the previous step.
• Under Viewer protocol policy, select HTTPS only.
• Save the configuration.

Step 3. Deploy the Lambda@Edge function

• In the Lambda console, create a new function using the Node.js 22.x runtime.
• For the execution role, select Create from AWS policy templates and choose Basic Lambda@Edge permissions.
• Add function code that rewrites the Host header to the origin domain and removes the /metrics prefix from the URI.
• Deploy the function and, under Actions, select Deploy to Lambda@Edge.
• Select your distribution, the created behavior, and the Origin request event.
• Confirm and wait for the deployment.

To verify, open https://yoursite.com.br/metrics in the browser. A 400 error indicates that the proxy is working correctly.