Slack Tic Tac Toe

Slack tic tac toe service that allows you to play tic tac toe with with someone in any slack channel

Rules

If your unfamiliar with the complex rules of tic tac toe, fret not! this wikipedia article will save your day!

There are a couple other rules when playing Tic Tac Toe in slack

• There can only be 1 game happening at a channel at one time
• Only the members that started the game and end a game
• You MUST play with emojies 😎

Commands

• /ttt challenge [@username] [:emoji:] To challenge a member to a game. Instead of an X, their symbol would be an emoji.
• /ttt accept [:emoji:] To accept a challenge and start a game. Instead of an O, their symbol would be an emoji.
• /ttt move [Cell Name] Place player emoji on a cell.
• /ttt quit Quit the current game on the channel (Either players can quit).
• /ttt status See the Status of the current board and who's turn in is.
• /ttt help See what commands are available.

Architecture

Board

The Architecture for this service is a simple. first we have generic board, player and cell classes that handle maintaining the game board and checking for winners

Game Engine

Then we have the game_engine tic_tac_toe, this class will validate moves, swap players, print the board and map moves.

Commands

Once we have a working game_engine and a board, the only thing left is to build and API that allows us to operate the game. Now, in the case of Slack slash commands, this comes in the form of a command Architecture. Based on the text param and the JSON post, we can parse it and determine which command to run.

Messaging the Slack channel all comes in the form of responses. The only time this services messages the slack room is due to a response of the POST request.

Game Tracker

GameTracker is composed of two global object and a module that maintains them. every active game sits in the global allActiveTicTacToeGames, which is hash where the key is channel_id and value is the game object. If the game object no longer lives in memory then the game doesn't exist any where.

allActiveTicTacToeGames is an object that live in memory, that means should the heroku box running the service where, be terminated, all the games are also lost. Furthermore since this service is deployed on the free tier of Heroku, after a short period of time the Dynos are scaled down to 0 meaning the service is reset. This also means that if a game is abandoned in the middle, the Dyno box will naturally clear out the game state. I call this a feature not a bug :P

GameTracker also handles the broadcasting and accepting of challenges. The process to start a game is

• broadcast a challenge against a user on a channel
• the user has to accept

However, multiple people can broadcast multiple challenges on the same channel. If any one of the challenges gets accepted, all other challenges on that channel get cleared. If the same person is challenged by 2 or more people, when that user accepts, the first challenge is accepted.

Installation

• clone the repo

git clone git@github.com:sh6khan/slack-tic-tac-toe.git
cd slack-tic-tac-toe

• Install the packages locally

npm install

• run the tests

npm test

All the tests are properly mocked, meaning that you wont need internet connection to run them

Deployed on Heroku

Check out getting started with heroku to see how this service is deployed.

This service is deployed on the free tier of Heroku and therefore service is atomically scaled down. This means the first command usually times out because Heroku is busy scaling it back up. 2nd requests and going forward work fine

The initialization of this service is the only time that we pull down the team member data and store in memroy. This means if a new team memeber is added to the slack team, the service will need to be restarted to pull the new team member data

Custom emojies are not supported 😢