Creating a Lobby System using Godot and Quarkus -
James Land - 11 Dec 2022
Introduction
Quick Background on My Choices
I want to write a real quick (ok not that quick) background on what inspired me to create and document this process. Feel free to skip ahead to the Architectures section, my feelings won’t be hurt… too much.
Originally, I wanted to create a simple multiplayer game that was basically a clone of the Secret Hitler boardgame(great game). A friend and I actually did create one using NodeJS and Spring but I wanted to update it to be a little more gamey and have some nicer transactions and animations. And I still wanted to be able to deploy my application to a server that was accessible using a normal browser, so I could play with my friends and they would not have to download anything.
Frontend Choice
While doing some searching online I found Godot, which ended up being almost exactly what I was looking for! It has a fairly nice UI that was not to hard to wrap my head around, and it felt easier to keep my code organized than something like Unity. Plus I was able to build my application using HTML5 which is exactly what I wanted. The one issue I found with it was trying to use it as my backend server. I know that it has a lot of great builtin capabilities as a backend server for a Godot frontend. But I found that trying to code business logic using Godot was a little more cumbersome than I would like. Plus I was having issues setting up connections to the mongo database I wanted to use. For that reason I decided to go with a different solution.
Backend Choice
I have a pretty hefty amount of previous experience using Java in my professional life which is probably why I gravitated to that for my backend. Specifically I have found that the relatively new framework Quarkus works very well as a server and has pretty good documentation online. Full discloser I am a Red Hat Employee (the original developer and main Opensource contributor for Quarkus) but I really do enjoy using it more than Spring at this point. Most importantly though I just find it much easier to organize the code for my business logic than I do in Godot. And it has a lot of existing integration libraries that make things like database connections easier.
Server Choice
I have played around with a couple different Cloud Technologies in the past, and honestly they all work fine. But while developing this application I started to mess around with Digital Ocean and just found it a little easier to parse than some of the other major providers, and the pricing is pretty cheap (it cost about $5 a month to keep up a low powered backend server following this guide. And less if you don’t leave the server up and running all the time).
Communication Choice
The final part I want to mention real quick is the communication between the frontend and backend are done using Websockets. More info about how this works can be found in the READMEs below.
Architectures
Most of the the more technical information can be found in the two repositories README files files. But I want to give a high level architectures picture here.
flowchart LR
subgraph gc[Godot Client]
gLogin(Login Scene)
gLobby(Main/Game Lobby Scene)
gGame(InGame Scene)
end
subgraph qs[Quarkus Server]
qLogin(Login Controller)
qLobby(Lobby Controller)
qGame(Game Controller)
cache[(In-Memory Cache)]
end
gLogin -- 1. User Log's In --> qLogin
gLogin -- 2. Change to Lobby Scene --> gLobby
gLobby -- "3. Show Main Lobby (All Games)" --> qLobby
gLobby -- 4. User Chooses/Creates Game --> qLobby
gLobby -- 5. Show Game Lobby --> qLobby
gLobby -- 6. Host Starts Game --> qLobby
gLobby -- 7. Change to InGame Scene --> gGame
gGame -- "8. InGame Commands (movement, turns, etc..)" --> qGame
style gc fill:#0B8384,stroke:#333,stroke-width:4px
style qs fill:#EE0000,stroke:#333,stroke-width:4px
Note: It is not super important you understand how any of this actually works for deployment purposes
Deployment
Suggested Technologies
All the deployment information is captured in the README files on the repositories which I will link below. My suggestion when trying to deploy these is to deploy locally first. And then try to deploy using Digital Ocean. I would also recommend deploying the backend server first, as the frontend server has some dependencies on it.
Backend Deployment
Information on the backend deployment can be found on the Backend’s Repositories README
Frontend Deployment
Information on the frontend deployment can be found on the Frontend’s Repositories README