EHB participant management system
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EHB Website Server

This is the source code for the application page for the European Harmony Brigade (EHB). It was developed by Alexander Koller for EHB 2015 and 2016, and rewritten from scratch in Python for EHB 2017. It provides the following functionality for the EHB registration process:

  • Participants can submit an application, and later book extras, and pay for both via Paypal.
  • Organizers can display and edit the applications.
  • Organizers can assign participants to rooms with a drag-and-drop room planner.
  • Organizers can generate printable materials, such as name badges and dance cards.


The EHB server requires Python 3. You will also need a working installation of an SQL database that is supported by SQLAlchemy, such as MySQL.

Make sure you have the following Python packages installed (replacing pymysql by the Python library for your database engine, if you use a database engine other than MySQL):

pip install pymysql Flask sqlalchemy Flask-SQLAlchemy-Session wtforms paypalrestsdk XlsxWriter openpyxl tornado flask_login numpy

If you want to generate printable materials, such as name badges, you will also need a reasonably recent and complete installation of LaTeX.

These requirements will be automatically installed if you are using a Docker container (see below).

Configuration files

The configuration for the EHB server is split over two files.

  • ehb-public.conf contains all the information which can safely be shared with the public, such as the event name, room prices, song list, and so on. This file is part of this public repository, and will be a (read-only) part of the Docker image.
  • Sensitive information, such as the details of the database connection, email passwords, and so on, should not be kept in ehb-public.conf. You can either write this information into a file ehb-private.conf, which you do not put under version control. If this file exists, the EHB server will read the information from there. Alternatively, you can set these options through environment variables, which are documented below. This is the most convenient choice for injecting them into a Docker container.

Private options

Here is a list of private options, together with their corresponding environment variables.

Environment variable Section Key
SERVER_SECRET server secret
SERVER_PORT server port
SERVER_BASEURL server base_url
SERVER_TORNADO server use_tornado
SERVER_LOGFILE server logfile
ACCEPT_APPLICATIONS application accept_applications
DB_URL database url
EMAIL_SERVER email server
EMAIL_SENDER email sender
EMAIL_NAME email name
EMAIL_PASSWORD email password
EMAIL_DELAY email delay_between_messages
PAYPAL_MODE paypal mode
PAYPAL_CLIENT_ID paypal client_id
PAYPAL_CLIENT_SECRET paypal client_secret

Furthermore, use environment variables of the following form to define the users who can login to the system:

EHB_USER_1: "organizers, EHB Organizers, orgapassword"

Running as a Docker container

The EHB apply server can be run in a Docker container. An up-to-date image should always be available on Docker Hub. This makes it unnecessary to install Python or any of the requisite libraries spelled out above; all these pieces are automatically part of the Docker image.

The EHB container needs to connect to a container providing a MySQL database over a (possibly Docker-internal) network. The simplest way to start both the MySQL container and the EHB server together is through Docker Compose, using the docker-compose.yml file in this repository. You should take care to choose your own database root password, as well as the MySQL data directory on your local machine (in services/mysql/volumes).

In order for the EHB server to function correctly, you will also need to supply values for the private configuration options (see above). The easiest way to do that is in a second docker-compose file - let's call it docker-compose-private.yml. This file is not part of this repository; it should look as follows:

version: '2'

      SERVER_SECRET: "blabla"
      SERVER_PORT: "5000"
	  ... and so on for the other variables ...

You can start the EHB server from within Docker with the following command:

docker-compose -f docker-compose.yml -f docker-compose-private.yml up

You can then access the EHB server on port 5000 on your local machine.

Initializing the database

The EHB system keeps its data in a MySQL database, which is stored in a subdirectory mysql_data below your main ehb2 directory. This subdirectory is created automatically when you first start the Docker containers as described above, and initially contains a fresh MySQL data directory with no databases. The initial root password is as specified in docker-compose.yml.

After starting the Docker containers, you should navigate to the web interface of the phpMyAdmin container at http://localhost:8080 and log in as root with the initial root password. You can modify the database configuration there, including a new root password (don't forget to also change it in docker-compose.yml if you do this). You can also create or import a database with EHB participant data through this web interface.

Once you have created or imported a database, change the database URL in your docker-compose-private.yml and restart the Docker containers. After this point, you should be able to navigate to the EHB2 admin page and e.g. look at the current participants.

Rebuilding the Docker image for development

If you make local changes to the EHB system (e.g. by editing the Python code) and restart the Docker containers, don't be surprised if your changes don't show up in your system. This is because the docker-compose.yml uses the Docker image akoller/ehb2 from Docker Hub by default, which is built from the latest version on Github.

If you want to test your local changes, you need to rebuild this Docker image locally by running the following command in the main ehb2 directory:

docker build -t akoller/ehb2 .

This will then use your own local code the next time you start the Docker containers.

Once you push to Github, the Docker image on Docker Hub will be automatically rebuilt.


This code uses Thunk by Reitanna, Powerup/Success by GabrielAraujo, and Postit Remove by Ignitor, all from Freesound under a Creative Commons licence.