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Maycamp Arena


Gemnasium Status Travis CI Status

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The idea of this project is to provide a grading system for competitions in informatics (IOI style). The main target group is high school students.

The system contains two main components:

  • Web part
  • Grader

The web part is a Ruby on Rails application, contained in the app folder.

The grader compiles the source code and runs the binary inside multiple docker containers and feeds each one with the given test cases. It monitors the consumption of the system resources - time limit, memory limit, etc..

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  • Participation in live contests.
  • Practicing old contests.
  • Grouping contests by categories.
  • Grouping problems by categories.
  • Evaluation of regular input/output tasks
  • Answer evaluation using checker
  • Supported programming languages:
  • C/C++
  • Java
  • Python 2 & 3
  • Possibility for integrating more than one grader on different machines.

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The following steps describe how to run the project on a local environment for developing purposes. The best and fastest way to get the project up and running is to use the already configured Vagrant virtual development environment.



  • Git
  • MySQL Server 5.5+ or MariaDB is preferred
  • Ruby 2.1+ (the easiest way is to use RVM or rbenv)


(for the virtual environment)


Web part

Download the project and initialize the virtual environment.

$ git clone
$ cd maycamp_arena
$ vagrant up

This last command may take a while to execute, considering the fact that the proper virtual box binary must be downloaded and provisioned.

Configure the ruby version. Keep in mind that rvm is already installed on the virtual machine.

NB! vm is just a placeholder for vagrant@vagrant-ubuntu-trusty64

$ vagrant ssh
vm$ rvm install 2.1.1
vm$ rvm use 2.1.1
vm$ cd /vagrant

Install the MySQL server. It is recommended to leave the root user without password (blank password), otherwise you should change the configurations.

vm$ sudo apt-get install mysql-server

Install the package dependencies and run the database migrations with:

vm$ bundle install
vm$ bundle exec rake db:create db:setup

After you have successfully completed the installation process of the web application you can start the server with:

$vm /vagrant/bin/rails server -b

and access it in your browser on localhost:3030.


Getting the grader up and running is done with:

vm$ cd /vagrant
vm$ gem install god
vm$ docker build -t grader .
vm$ printf "vagrant-ubuntu-trusty-64:\n rsync: /vagrant/sets" > config/grader.yml

and running it with:

vm$ /home/vagrant/.rvm/bin/rvm 2.1 do bundle exec rake RAILS_ENV=production grader:start

Running the tests

To run the tests execute:

$ bundle exec cucumber


After you have successfully set up the project you can log in with the dummy admin account:

username: root
password: 123123

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Deployment is done using docker stack. Follow these steps:

  • Provision a machine with docker
  • Checkout the code of the repository in /app. This is important as the location of the app in the deployment should be the same as on the host machine.
  • Init docker swarm by running docker swarm init
  • Generate new SECRET_KEY_BASE and SECRET_TOKEN and put them in docker-compose.yaml. Use openssl rand --hex 64 to generate the secrets
  • Change the SIDEKIQ_USERNAME and SIDEKIQ_PASSWORD to something more secure
  • Set the mailgun key and domain so that the system can send emails
  • Generate the docker image used for grading by running docker build -f grader.Dockerfile -t grader .
  • Run docker stack deploy maycamp --compose-file docker-compose.yaml to deploy the app
  • Find the ID of the maycamp_web container by running docker ps and init the DB docker exec <container_id> rake db:setup

The app should be accessible from the IP address of the provisioned machine. By default it binds on port 80.

WARNING: The current deployment has some limitations:

  • It runs only on a single node clusters. This is because it uses shared volumes to communicate between the different services
  • It requires to checkout the code in the /app folder on the host machine. This is because the grader service connects directly to the docker host server and spawns the grading containers with volumes mounted to the host machine. Once the communication between the container based on volumes is removed, this limitation will be removed.


This is the grading system behind It started as a fork of spoj0, but at the end was almost completely reimplemented.






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