CG Arena

Local bot arena similar to CodinGame.

Features

• Web UI
  • Add/Delete bots
  • Check leaderboard
• Matchmaking
• Rating calculation
  • OpenSkill

Installation

You would need cargo installed (here is how to install it).

cargo install cgarena

The same command can be used to update CG Arena to the latest version.

Usage

1. To create a new arena in the current folder run:

   cgarena init
   

2. To run arena previously initialized in the current folder run:

   cgarena run
   
   

Configuration

cgarena init command generates cgarena_config.toml file including default config. You can check the contents of the default config here.

The config file is documented, so read through it and don't forget to restart the arena if you make any changes to the config file.

Worker configuration

Worker configuration has 3 important properties:

• cmd_play_match
• cmd_build
• cmd_run

Here are some good defaults for them:

cmd_play_match = "python play_game.py {SEED} {PLAYERS}"
cmd_build = "sh build.sh {DIR} {LANG}"
cmd_run = "sh run.sh {DIR} {LANG}"

You would also need to create following files in the arena folder:

CodinGame compatible play_game.py (slightly modified version from Psyleague readme)

import sys, subprocess, random, json, tempfile, os
if __name__ == '__main__':
    f, log_file = tempfile.mkstemp(prefix='log_')
    os.close(f)

    n_players = len(sys.argv) - 2
    seed = sys.argv[1]
    # assumes brutaltester-compatible referee.jar is placed in the same folder
    cmd = 'java --add-opens java.base/java.lang=ALL-UNNAMED -jar referee.jar' + ''.join([f' -p{i} "{sys.argv[i + 1]}"' for i in range(1, n_players+1)]) + f' -d seed={seed} -l "{log_file}"'
    task = subprocess.run(cmd, shell=True, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
    with open(log_file, 'r') as f:
        json_log = json.load(f)
    os.remove(log_file)
    p_scores = [int(json_log['scores'][str(i)]) for i in range(n_players)]
    rv = {}
    rv['ranks'] = [sum([int(p_score < p2_score) for p2_score in p_scores]) for p_score in p_scores] # assumes higher score is better
    rv['errors'] = [int(p_score < 0) for p_score in p_scores] # assumes negative score means error
    print(json.dumps(rv))

Generic build.sh which can support multiple programming languages

if [ "$2" = "c++" ]; then
  g++ -std=c++17 -x c++ "$1"/source.txt -o "$1"/a.exe
elif [ "$2" = "python" ]; then
  cp "$1"/source.txt "$1"/a.py
else
  echo "Unsupported language '$2'" >&2
fi

Generic run.sh which can support multiple programming languages

if [ "$2" = "c++" ]; then
  ./"$1"/a.exe
elif [ "$2" = "python" ]; then
  python ./"$1"/a.py
else
  echo "Unsupported language '$2'" >&2
fi

For languages which need project folder (e.g. Rust) you build bot the following way:

• somewhere create single project which has all the dependencies installed
• inside build.sh copy source.txt to that project folder (e.g. main.rs for Rust)
• build the project
• copy the executable from the project build to the bot directory

Building from source

To build CG Arena from source code run the following (make sure cargo and npm are installed):

git clone https://github.com/aangairbender/cgarena.git
cd cgarena
cargo build --release

You can find executable in /target/release folder.