README.md

Word Battle

Multiplayer word guessing game, built with:

• Elixir & Phoenix
• Svelte
• Tailwind

Development

The back-end requires word lists for valid guesses and solutions. By default, these are loaded from ./words/valid_guesses.txt and ./words/solutions.txt. These files are not provided with the repository, so you should create your own word lists there. Each word must be on a separate line:

weary
pilot
pills
blush
focal

After creating the word files, run the following:

mix setup
mix phx.server

Now you can visit localhost:4000 from your browser.

You can also run it as a container:

podman build -t word-battle .
podman run --rm -p 4000:4000 -e SECRET_KEY_BASE=secret -e FLY_APP_NAME=word-battle -e PHX_HOST=localhost word-battle:latest    

Multi-node configuration

The application can run on multiple nodes, which can all be clustered together automatically, allowing the user to pick which node they want to play the game on. You can run the following commands in two different terminals:

REGION=R1 iex --sname r1 -S mix phx.server
REGION=R2 iex --sname r2 -S mix

This will run the application in both terminals, which should automatically connect together. In the game UI, you will then be able to pick between the nodes.

Deployment

For deployment, Mix releases and Docker are used. The Dockerfile handles this automatically:

docker build .

During the Docker build, word lists are automatically copied from ./words/solutions.txt and ./words/valid_guesses.txt and bundled into the image. This allows for an easier deployment without any static storage requirements.

Environment variables

• SOLUTIONS - Required. Path to the file with solution words
• VALID_GUESSES - Required. Path to the file with valid guess words
• WORD_LENGTH - Optional, defaults to 5. Any words that are not this length will be discarded.
• REGION - Optional. The region name for the node. This will be displayed in the node selection. Defaults to $FLY_REGION in deployment.

Back-end architecture

The lifecycle of a player is as follows:

1. The user joins the player:lobby channel
2. Through that channel, the user joins the queue on a node
3. Once the queue fills, a game is created
4. The user receives a token that authenticates them for that game
5. The user joins the channel for that game

Process tree

On the server, the process lifecycle for queueing looks roughly like this: