docker-compose.yaml

services:
   shiny:
      build:
         context: .
         dockerfile: DOCKERFILE
      container_name: fe_shiny
      restart: always
      ports:
         - "3838:3838"
      volumes:
         - "./shiny-data:/srv/shiny-server/survey"
      command: ["R", "--vanilla", "-e", "shiny::runApp('/srv/shiny-server/survey', host='0.0.0.0', port=3838)"]

   postgres:
      # a name, e.g.,  db_container is instrumental to be
      # called as host from the shiny app
      container_name: db_container
      image: postgres:15-alpine
      restart: always
      environment:
         - POSTGRES_USER=postgres
         - POSTGRES_PASSWORD=postgres # Don't use passwords like this in production
      # This port mapping is only necessary to connect from the host,
      # not to let containers talk to each other.
      # port-forwarding: from host port:to docker port -> mapping
      ports:
         - "1111:5432"
      # if container killed, then data is still stored in volume (locally)
      volumes:
         - "./pgdata:/var/lib/postgresql/data"