Installation

This guide will help you to install pretalx on a Linux distribution, as long as the prerequisites are present.

We also provide an Ansible role that follows this guide, in case you already have an Ansible-based setup. If you prefer a docker setup, please use our docker-compose setup.

Step 0: Prerequisites

Please set up the following systems beforehand, we’ll not explain them here (but see these links for external installation guides):

  • Python 3.6 or 3.7 and a pip to match. You can use python -V and pip3 -V to check.
  • An SMTP server to send out mails
  • An HTTP reverse proxy, e.g. nginx or Apache to allow HTTPS connections
  • A MySQL (5.6 or higher) or PostgreSQL (9.4 or higher) database server (you can use SQLite, but we strongly recommend not to run SQLite in production)
  • A redis server

We also recommend that you use a firewall, although this is not a pretalx-specific recommendation. If you’re new to Linux and firewalls, we recommend that you start with ufw.

Note

Please do not run pretalx without HTTPS encryption. You’ll handle user data and thanks to Let’s Encrypt, SSL certificates are free these days. We also do not provide support for HTTP-exclusive installations except for evaluation purposes.

Step 1: Unix user

As we do not want to run pretalx as root, we first create a new unprivileged user:

# adduser pretalx --disabled-password --home /var/pretalx

In this guide, all code lines prepended with a # symbol are commands that you need to execute on your server as root user (e.g. using sudo); you should run all lines prepended with a $ symbol as the unprivileged user.

Step 2: Database setup

Having the database server installed, we still need a database and a database user. We recommend using PostgreSQL, although pretalx also works (and is tested against) MariaDB and SQLite. For databases other than PostgreSQL, please refer to their documentation on how to set up a database and a database user with the appropriate permissions:

# sudo -u postgres createuser pretalx -P
# sudo -u postgres createdb -O pretalx pretalx

When using MySQL, make sure you set the character set of the database to utf8mb4, e.g. like this:

mysql > CREATE DATABASE pretix DEFAULT CHARACTER SET utf8mb4 DEFAULT COLLATE utf8mb4_unic

Step 3: Package dependencies

To build and run pretalx, you might need local system packages beyond the dependencies mentioned above. Due to the impossibility of maintaining an up to date list for all Linux flavours out there, we sadly can’t provide one here.

If you’re running Ubuntu or a similar system, you’ll probably want to install packages like build-essential, libssl-dev, and gettext, plus libmysqlclient-dev if you use MariaDB.

Please note that pretalx requires Python 3.6 or Python 3.7 – if your operating system doesn’t come with one of those Python versions, please either find an alternative source for your system, or build it from source.

Note

You may need to replace all following mentions of pip with pip3.6.

Step 4: Configuration

We now create a configuration directory and configuration file for pretalx:

# mkdir /etc/pretalx
# touch /etc/pretalx/pretalx.cfg
# chown -R pretalx:pretalx /etc/pretalx/
# chmod 0600 /etc/pretalx/pretalx.cfg

Fill the configuration file /etc/pretalx/pretalx.cfg with the following content (adjusted to your environment):

[filesystem]
data = /var/pretalx/data
media = /var/pretalx/data/media
logs = /var/pretalx/data/logs

[site]
debug = False
url = https://pretalx.mydomain.com

[database]
backend = postgresql
name = pretalx
user = pretalx
password = pretalx
host = localhost
port = 5432

[mail]
from = admin@localhost
host = localhost
port = 25
user = admin
password = something
tls = False
ssl = True

[celery]
backend = redis://127.0.0.1/1
broker = redis://127.0.0.1/2

Check out Configuration for details on the available configuration options.

Step 5: Installation

Now we will install pretalx itself. Please execute the following steps as the pretalx user. We will install all Python packages, including pretalx, in the user’s Python environment, so that your global Python installation will not know of them:

$ pip install --user -U pip setuptools wheel pretalx gunicorn

pretalx works your choice of database backends – we recommend using PostgreSQL, but MySQL, SQLite, and Oracle work as well. Use the following command to install the database driver (unless you use SQLite, which has its driver built in):

Database pip package
PostgreSQL pip install --user -U psycopg2-binary
MySQL pip install --user -U mysqlclient
Oracle pip install --user -U cx_Oracle

We also need to create a data directory:

$ mkdir -p /var/pretalx/data/media

We compile static files and translation data and create the database structure:

$ python -m pretalx migrate
$ python -m pretalx rebuild

Now, create a user with administrator rights, an organiser and a team by running:

$ python -m pretalx init

Step 6: Starting pretalx as a service

We recommend starting pretalx using systemd to make sure it starts up after a reboot. Create a file named /etc/systemd/system/pretalx-web.service with the following content:

[Unit]
Description=pretalx web service
After=network.target

[Service]
User=pretalx
Group=pretalx
WorkingDirectory=/var/pretalx/.local/lib/python3.6/site-packages/pretalx
ExecStart=/var/pretalx/.local/bin/gunicorn pretalx.wsgi \
                      --name pretalx --workers 4 \
                      --max-requests 1200  --max-requests-jitter 50 \
                      --log-level=info --bind=127.0.0.1:8345
Restart=on-failure

[Install]
WantedBy=multi-user.target

If you decide to use Celery (giving you asynchronous execution for long-running tasks), you’ll also need a second service /etc/systemd/system/pretalx-worker.service with the following content:

[Unit]
Description=pretalx background worker
After=network.target

[Service]
User=pretalx
Group=pretalx
WorkingDirectory=/var/pretalx/.local/lib/python3.6/site-packages/pretalx
ExecStart=/var/pretalx/.local/bin/celery -A pretalx.celery_app worker -l info
WorkingDirectory=/var/pretalx
Restart=on-failure

[Install]
WantedBy=multi-user.target

You can now run the following commands to enable and start the services:

# systemctl daemon-reload
# systemctl enable pretalx-web pretalx-worker
# systemctl start pretalx-web pretalx-worker

Step 7: SSL

The following snippet is an example on how to configure a nginx proxy for pretalx:

server {
    listen 80 default_server;
    listen [::]:80 ipv6only=on default_server;
    server_name pretalx.mydomain.com;
}
server {
    listen 443 default_server;
    listen [::]:443 ipv6only=on default_server;
    server_name pretalx.mydomain.com;

    ssl on;
    ssl_certificate /path/to/cert.chain.pem;
    ssl_certificate_key /path/to/key.pem;

    add_header Referrer-Options same-origin;
    add_header X-Content-Type-Options nosniff;

    location / {
        proxy_pass http://localhost:8345/;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto https;
        proxy_set_header Host $http_host;
    }

    location /media/ {
        alias /var/pretalx/data/media/;
        add_header Content-Disposition 'attachment; filename="$1"';
        expires 7d;
        access_log off;
    }

    location /static/ {
        alias /path/to/static.dist/;
        access_log off;
        expires 365d;
        add_header Cache-Control "public";
    }
}

We recommend reading about setting strong encryption settings for your web server.

You’ve made it! You should now be able to reach pretalx at https://pretalx.yourdomain.com/orga/ and log in as the administrator you configured above. You can now create an event, and off you go!

Step 8: Check the installation

You can make sure the web interface is up and look for any issues with:

# journalctl -u pretalx-web

If you use Celery, you can do the same for the worker processes (for example in case the emails are not sent):

# journalctl -u pretalx-worker

In the start-up output, pretalx also lists its logging directory, which is also a good place to look for the reason for issues.

Next Steps

Check out Configuration for details on the available configuration options.

Have a look at our Maintenance documentation to read about updates, backups, and monitoring.