Distribute Private Content with CloudFront Signed URLs

Generate a signed URL with a short expiry so a user can download a protected asset without the bucket being public.

~25 mincloudcloudfrontsigned-url

Task

Configure aws cloudfront get-signature --url https://cdn.example.com/file.pdf --key-pair-id $KEY_ID --private-key-file pk.pem so the cloud resource enforces the control automatically without manual console steps.

When to use this

An audit finds that aws cloudfront get-signature --url https://cdn.example.com/file.pdf --key-pair-id $KEY_ID --private-key-file pk.pem was configured manually and drifted, leaving a resource exposed for two weeks.

Prerequisites

Terraform or IaC tooling installed
Cloud provider credentials with target permissions

Steps

1. Configure aws cloudfront get-signature --url https://cdn.example.com/file.pdf --key-pair-id $KEY_ID --private-key-file pk.pem in the project configuration file with the recommended defaults.

aws cloudfront get-signature --url https://cdn.example.com/file.pdf --key-pair-id $KEY_ID --private-key-file pk.pem

Expected output: The configuration is accepted and aws cloudfront get-signature --url https://cdn.example.com/file.pdf --key-pair-id $KEY_ID --private-key-file pk.pem runs without errors on the first invocation.

2. Run the check locally to verify aws cloudfront get-signature --url https://cdn.example.com/file.pdf --key-pair-id $KEY_ID --private-key-file pk.pem produces the expected result before pushing.

pnpm test

Expected output: Local run matches CI behavior; no surprises after push.

3. Add the gate to the CI pipeline so aws cloudfront get-signature --url https://cdn.example.com/file.pdf --key-pair-id $KEY_ID --private-key-file pk.pem blocks merge on failure.

- name: Run add cloudfront signed url
  run: pnpm test

Expected output: Pull requests with failing aws cloudfront get-signature --url https://cdn.example.com/file.pdf --key-pair-id $KEY_ID --private-key-file pk.pem are blocked from merging.

Troubleshooting

Problem

The check passes locally but fails in CI

Solution

Pin dependency versions and the runtime to match CI exactly; reproduce with the same Docker image or act.

Problem

Configuration is rejected with a schema error

Solution

Check the tool version matches the config schema; older versions may not support newer fields.

Limitations

The gate only runs on events that trigger the workflow; locally pushed commits bypass it.
Configuration drift is possible if someone edits settings outside version control.

Codify the control

Start by measuring the problem. Generate a signed URL with a short expiry so a user can download a protected asset without the bucket being public. The most common mistake is adding the gate without first confirming it catches the issue you care about. Run aws cloudfront get-signature –url https://cdn.example.com/file.pdf –key-pair-id $KEY_ID –private-key-file pk.pem against the current codebase and inspect the output before wiring it into CI.

aws cloudfront get-signature --url https://cdn.example.com/file.pdf --key-pair-id $KEY_ID --private-key-file pk.pem

Detect drift

Once the gate is in place, make failures actionable. A failing aws cloudfront get-signature –url https://cdn.example.com/file.pdf –key-pair-id $KEY_ID –private-key-file pk.pem should point to the exact file and line, not a generic error. Pin the tool version in the lockfile so a upstream release does not silently change behavior. Review the gate output in every pull request just like a test result.