The following environment variables are set by the runtime environment:

Environment variable Description
GAE_INSTANCE The name of the current instance.
GAE_MEMORY_MB The amount of memory available to the application process.
GAE_SERVICE The service name specified in your application’s app.yaml file, or if no service name is specified, it is set to default.
GAE_VERSION The version label of the current application.
GOOGLE_CLOUD_PROJECT The Project ID associated with your application, which is visible in the Google Cloud Platform Console
NODE_ENV When your app is deployed, the value is production.
PORT The port that will receive HTTP requests. Set to 8080.

노드에선 아래와 같이 참조