You could create your own image that:
- Contains your schema
- Checks on the health of your alpha server (http://<server_addr>:8080/health)
- When it’s in a healthy state, update the schema via your preferred programming language (go, python, ts) with network requests. For an example of a go-based schema updater used in testing, check out dgraph-docker-helper/dgraph.go at 47df976ddb6e748ddb2ee71184401fcb7d1037b7 · matthewmcneely/dgraph-docker-helper · GitHub
Also in your docker-compose file, make this image dependent on alpha.