In that example we don't need to run the webpack build inside the Docker image when the container is started. There are multiple points in the application deplo

In that example we don't need to run the webpack build inside the Docker image when the container is started. There are multiple points in the application deployment lifecycle where a webpack build could be performed. When you deploy with the gcloud cli a Docker image will be packaged for you and and deployed. You could easily run a webpack build before the image is packaged so the built files get packaged as well, or extend the image with your own Dockerfile to customize the Docker steps, or build the image yourself locally and deploy your already built image, etc...