Deploy an web application that does requires no client-side install and does some process on the backend. Make it run on a bare cloud instance start/stoppable with a single command.
This app posts notifications to a page segregated by a logical name... a "room." Messages are appended to previous messages. If there are no updates after about 20 seconds, the state is cleared.
The application has been installed as a systemd service. In the infra directory, there's an ansible script to install it as a systemd service named "cloudservice". There's also terraform to launch an EC2 instance with the systemd service named "app".
The application was packages as a docker image. So the update process is 2 commands:
- sudo docker pull sweeneyb/stomp
- sudo systemctl restart cloudservice
- Change the tag in the user-data in
infra/tf-aws/main.tfand re-apply the terraform. This will create a new instance with the updated code.
I wanted to show a basic framework that was capable of 2 way, asynchronous communication from the client to the server. I also wanted to show how components written in different langauges (java and javascript) can interact. Finally, I wanted to the backend to be easy to manage. Docker + a systemd service seemed like the easiest management after using ansible to get everything ready.
The frontend is written in Vue, but is very basic. Most of it came from https://stackoverflow.com/questions/46818674/spring-stomp-websockets-with-vue-js?rq=1, with some modification to show I can get around. Frontend is definitely my weakest area, so I spent just enough time getting things running. In the future, I'd like to use the Vue router to add new games and the room subscriptions to run multiple instances of games.
The backend is java 8+, but would I think I would have preferred Kotlin. I pulled most of the websocket interaction code from https://spring.io/guides/gs/messaging-stomp-websocket/, but added a few things. There's a REST endpoint that will add a message that isn't coming through the websocket. There's also some abstraction of game creation to demonstrate how multiple game types could be supported. The "games" are event based, which should support a lot of different gameplay flows. The games are also abstracted behind a service, which could easily be moved to a database or redis. Future work is to actually implement game rules and let the frontend create instances of those game flows.
This project isn't big enough for CI/CD, but I do have some helper scripts. See fullBuild.sh. I've also included terraform to create a project & vm in GCP to be used as a dev envionment.
Docker was the obvious packaging, as it makes it easy to run anywhere. If you have an existing cloud instance, there's just enough ansible to get docker installed & a systemd unit file installed. If you want to deploy into a new instance, see the tf-aws folder in infra.