There are the main configuration options to set to have nuancier running. These options are all present and described in the nuancier.cfg file.

The secret key

Set in the configuration file under the key SECRET_KEY, this is a unique, random string which is used by Flask to generate the CSRF key unique for each user.

You can easily generate one using pwgen for example to generate a 50 characters long random key

pwgen 50

The database URL

Nuancier uses SQLAlchemy an SQL Toolkit and Object Relationship Mapper in Python, and is used to connect to the database. In order to connect to the database, you need to provide the database name in a URL format under the key DB_URL in the configuration file.

Examples URLs are:



The key sqlalchemy.url of the alembic.ini file should have the same value as the DB_URL described here.

The admin group

Nuancier relies on a group of administrator to create new elections, open or close them for voting and open or close the publication of the results and (re)generate the cache. The ADMIN_GROUP field in the configuration file refers to the FAS group that manages this nuancier instance.

See Usage for details explanations on the different administration layer of nuancier.


Several groups of administrators can be set using either () or [].

The pictures folder

The PICTURE_FOLDER field takes the full path to the folder in which the application will place all the pictures submitted by the candidates (within a folder, specific for each election).

The cache folder

The CACHE_FOLDER field takes the full path to the folder in which the application is allowed to generate the thumbnails of the pictures present in the PICTURE_FOLDER.


This folder should be write-able by the application (ie: apache).

The thumb size

In order to reduce the size(and hence the loading time) of the pages displaying all the pictures submitted by a candidate to an election, nuancier creates thumbnails of these pictures. These thumbnails are generated with anti-aliases to maintain a certain quality.

The THUMB_SIZE is a set of length, width coordinate providing indication to nuancier about the desired size of the thumbnails.

By default THUMB_SIZE is at 256x256.


It is a good practice to have the cookies require a https connection for security reason. However, while developing, this can prevent the authentication from working. So by default this is turned off to provide an out-of-the-box working configuration, however you will want to change it in production.



Change this SESSION_COOKIE_SECURE = True when using the application in a production environment.