In this lab, you’ll be tasked with deploying an off-the-shelf Cloud Run application that takes headless screenshots of web page URLs. The screenshots are written to a Google Cloud Storage bucket. However, to reduce an attack vector and pass an internal security audit, you must ensure your public web service has no actual access to Google Cloud Storage. To accomplish this, you will deploy a public frontend, which can only speak to the backend. The backend itself must also follow the principle of least privilege. To perform this hands-on lab, you should be familiar with the Cloud Shell and have some experience with Cloud Run.
Learning Objectives
Successfully complete this lab by achieving the following learning objectives:
- Build the Frontend and Backend Container Images
Obtain the code from GitHub:
git clone https://github.com/timhberry/screenshot screenshot-backendCreate a Cloud Storage bucket in your project with the naming convention:
your-project-screenshots.Update
screenshot.jsin the backend application, replacing the values ofGOOGLE_CLOUD_PROJECT_IDandBUCKET_NAMEwith your project ID and the name of the bucket you just created.Use Cloud Build to create container images called
screenshot-frontendandscreenshot-backend, and store them in Container Registry in your project.
- Deploy the Backend Service
Create a service account for the backend service called
backend-identity.Create an IAM policy binding for the project that grants this service account the role of
roles/storage.objectCreator. (Hint: Use thegcloud projects add-iam-policy-bindingcommand.)Deploy the
screenshot-backendservice, using thebackend-identityservice account as its runtime identity. Do not allow unauthenticated invocations, and grant512mebibytes of memory to the service.Test that the service has been deployed successfully with
curlin the Cloud Shell terminal. First, obtain an auth token:TOKEN=$(gcloud auth print-identity-token)Access your service URL, with the token in the header, specifying a further URL to screenshot (in this example, we screenshot google.com):
curl -H "Authorization: Bearer $TOKEN" https://<SCREENSHOT-BACKEND_URL>.run.app/?url=https://www.google.com
- Deploy the Frontend Service
- Create a service account for the frontend service called
frontend-identity. - Create an IAM policy binding that says the
frontend-identityservice account is permitted to invoke thescreenshot-backendservice. (Hint: Use thegcloud run services add-iam-policy-bindingcommand.) - Deploy the
screenshot-frontendservice, using thefrontend-identityservice account as its runtime identity. Allow unauthenticated invocations, and use--set-env-varsto set aBACKEND_URLenvironment variable with thebackend-serviceURL as its value. - If you are successful, you should be able to access your frontend service and provide it with a URL to screenshot, then find that screenshot in your GCS bucket.
- Create a service account for the frontend service called
