To get a consistent development environment, we use Nix to install Python and the project dependencies. The development environment also includes PostgreSQL, linters, a SASS compiler and pytest for running the tests.
The following code snippets are written for ekklesia-portal but also work for ekklesia-voting when you change the project name.
Installation instructions taken from Getting Nix. See the link for other installation methods.
Nix is currently supported on Linux and Mac. The quickest way to install Nix is to open a terminal and run the following command (as a user other than root with sudo permission):
curl -L https://nixos.org/nix/install | sh
Make sure to follow the instructions output by the script. The installation script requires that you have sudo access to root.
A good way to get a development shell is to use
Lorri which improves the builtin
nix-shell command. Another option is to use nix-direnv as described in the next section.
lorri (also works for updates):
nix-env -i lorri
This is enough to use
lorri shell needed for the quick start section
We also recommend using the
direnv integration. This will
automatically enter the development shell when changing to the project
directory. Please follow the Lorri Installation
Setting up nix-direnv
Instead of lorri (described above), you can also use direnv <https://direnv.net>`_ with nix-direnv to get a automatically updating development shell. See the linked pages for instruction on how to set them up.
Setting up the Cachix Binary Cache
To speed up installation, you should add the edemocracy binary cache hosted on Cachix.
If your user can edit Nix config files (when using a single-user installation on a non-NixOS system, for example), just install the Cachix client and add the edemocracy cache:
nix-env -i cachix cachix use edemocracy
If cachix cannot change the config, it will instructions on how to do it.
On NixOS, you have to run cachix as root (
sudo cachix use edemocracy) or another trusted Nix user.
Running PostgreSQL as User
You can run a PostgreSQL database server with your user permissions if you don’t want to use an existing database server. Run the pg_ctl commands from the nix shell.
Run as user:
pg_ctl -D ~/postgresql init postgres -D ~/postgresql -k /tmp -h ''
Create database (in another terminal):
createdb -h /tmp ekklesia_portal
You can connect to the database with psql now:
psql -h /tmp ekklesia_portal
Use the following connection string in the app config file:
database: uri: "postgresql+psycopg2:///ekklesia_portal?host=/tmp"
Updating The Development Environment
lorri shell always installs changed dependencies and tools before
entering the development shell which takes some seconds.
When using the
direnv integration, running
lorri daemon in the
background automatically updates the development shell when something
changes. Press Enter in the development shell to trigger the first
daemon build or to see the changes in the shell made by
You can also trigger an update by running
lorri watch --once if you
don’t want to run
Editor / IDE Integration
Tested with VSCode, Pycharm
Run this to build the environment:
This creates a directory
pyenv that is similar to a Python virtualenv.
The Environment should be picked up by the IDE using the Python interpreter
in the directory. A restart may be required.