/xm-battlesnake-java

Primary LanguageJava

xm-battlesnake-java

A simple BattleSnake AI written in Java using Spring Boot, which can easily be deployed to Heroku. Spring Boot provides a simple and easy way to implement rest services required by your snake. This tutorial will help you get started (https://spring.io/guides/gs/actuator-service/).

This application supports the Getting Started with Java on Heroku article - check it out.

Pre-requisite Accounts

Every team must show up with a laptop and create the following accounts in order to use the provided start snake. You are welcome to use existing accounts if you have them already.

Prerequisite Software

You'll need the follwing software on your computer before you can get started with this project:

You'll need the follwing software on your computer if you want to compile and run the application locally. This is completely optional but probably desired since troubleshooting coding errors and testing behaviour will be much easier.

If you have the software installed already, confirm by running the respective commands on the command prompt and check the versions:

  • javac -version
  • mvn --version
  • git --version
  • heroku --version

Preparing your project

DON'T SKIP THIS STEP. You'll need your own copy of this project under your own GitHub account in order to make and publish changes to your snake.

  • Make sure you are signed in to your GitHub account
  • Fork this project

Test Your Environment Setup

At this point, make sure that all of you software is installed, and you've forked this project correctly. Run the following commands:

$ git clone https://github.com/<your account>/xm-battlesnake-java.git
$ cd xm-battlesnake-java
$ mvn install  (or ./mvnw install)
$ heroku local

Your app should now be running on localhost:5000/health.

Testing your local app

You can use curl commands to easily test if you snake is working and responding to end points.

Run it locally using heroku command:

$ heroku local

/start Endpoint

$ curl localhost:5000/start -X POST -H "Content-Type: application/json" -d '{"width":20,"height":20,"game_id":"example-game-id"}'

/move Endpoint

$ curl localhost:5000/move -X POST -H "Content-Type: application/json" -d '{ "you": "2c4d4d70-8cca-48e0-ac9d-03ecafca0c98","width": 2,"turn": 0,"snakes": [{ "taunt": "git gud","name": "my-snake","id": "2c4d4d70-8cca-48e0-ac9d-03ecafca0c98","health_points": 93,"coords": [[0,0],[0,0],[0,0]] },{ "taunt": "gotta go fast","name": "other-snake","id": "c35dcf26-7f48-492c-b7b5-94ae78fbc713","health_points": 50,"coords": [[1,0],[1,0],[1,0]] }],"height": 2,"game_id": "a2facef2-b031-44ba-a36c-0859c389ef96","food": [[1,1]],"dead_snakes": [{ "taunt": "gotta go fast","name": "other-snake","id": "83fdf2b9-c8d0-44f4-acb2-0c506139079e","health_points": 50,"coords": [[5,0],[5,0],[5,0]] }] }'

Deploying to Heroku

You will be provided a heroku project name to deploy your snake to inside your git repo do the following commands

$ heroku git:remote -a [HEROKU_PROJECT_NAME]

then everytime you want to deploy changes you can simply do

 $ git push heroku master

The output should end with the URL endpoint of your snake. Use this URL to add your snake to a game on the server.

remote: -----> Launching...
remote:        Released v3
remote:        https://my-snake.herokuapp.com/ deployed to Heroku
remote:
remote: Verifying deploy... done.

Testing the app

Your app should now be running on https://[HEROKU_PROJECT_NAME].herokuapp.com/health. You can use curl commands to easily test if you snake is working and responding to end points.

/start Endpoint

$ curl https://my-snake.herokuapp.com/start -X POST -H "Content-Type: application/json" -d '{"width":20,"height":20,"game_id":"example-game-id"}'

/move Endpoint

$ curl https://my-snake.herokuapp.com/move -X POST -H "Content-Type: application/json" -d '{ "you": "2c4d4d70-8cca-48e0-ac9d-03ecafca0c98","width": 2,"turn": 0,"snakes": [{ "taunt": "git gud","name": "my-snake","id": "2c4d4d70-8cca-48e0-ac9d-03ecafca0c98","health_points": 93,"coords": [[0,0],[0,0],[0,0]] },{ "taunt": "gotta go fast","name": "other-snake","id": "c35dcf26-7f48-492c-b7b5-94ae78fbc713","health_points": 50,"coords": [[1,0],[1,0],[1,0]] }],"height": 2,"game_id": "a2facef2-b031-44ba-a36c-0859c389ef96","food": [[1,1]],"dead_snakes": [{ "taunt": "gotta go fast","name": "other-snake","id": "83fdf2b9-c8d0-44f4-acb2-0c506139079e","health_points": 50,"coords": [[5,0],[5,0],[5,0]] }] }'

Pushing Updates to Heroku

You have to commit your changes to your git project as part of pushing them to the remote heroku git.

$ git add --all; git commit -m "Updated";
$ git push heroku master

Debugging Logs on Heroku

Once your snake is running, you can tail the logs any time in the console using the command:

$ heroku logs --tail

Local Development

In order to shorten the devlopment cycle, or do step-through debugging, you probably want to develop locally. Firstly, run a game server locally using docker:

$ docker run -it -p 4000:4000 stembolt/battle_snake

Leave this running and go to http://localhost:4000, you should see a grey screen. Meanwhile, you want to get your snake running locally. In your local directory where you checked out the Git project, run...

$ ./mvnw idea:idea
--OR--
$ ./mvnw eclipse:eclipse

... to have maven prepare a project for your IDE. Create a project as you would any Maven project. (Eclipse File -> Import -> Maven -> Existing Maven Projects). You can run / debug the project by running the /src/main/java/com/battlesnake/Main.java as a normal java process. (You can probably turn off heroku local at this point). Mine runs through Heroku on local port 5000, yours might be different.

Now you can try your snake out on your local game server. Since the server is running in a docker container, and your snake is running outside that container, you need to determine your IP address so that the server can talk to your local snake. Maybe use something like ifconfig or check your System Preferences. Once you figure that out, click "New Game" on your game server running at localhost:4000.

You might want a smaller board than 20x20, and a much longer API timeout which will give you time to step-through debug your snake. Enter your snake's location in the Snake's url section using your IP address (e.g. mine is http://10.3.6.123:8080). Play around with the singleplayer / multiplayer Game Mode setting. You can enter multipe versions of your own snake. If you want someone to fight against, my snake is running at https://stk-battlesnake.herokuapp.com

Once you get to the point where you want your real snake (running on Heroku which we will use for the competition) to reflect your local development, go through the "Pushing Updates to Heroku" step above, wait a few seconds, and your new and improved snake will be running up on Heroku.

Documentation

For more information about using Java on Heroku, see these Dev Center articles: