To run a local copy of Prometheus that will emit an alert you can build and run the following container:
docker build -t my-prom ./testlocal docker run -p 9090:9090 --net="host" my-prom
Make sure alert-to-pubsub is running locally at port 8000.
Indices are in ../ds/index-skia-public.yaml and can be created using:
gcloud datastore create-indexes index-skia-public.yaml