Introduction

OpenBSD 7.6 has ports for Radicale 1.x and 2.x but not for 3.x. Given the recent fairly active development of Radicale a port for Radicale 3.x would become outdated rapidly. As an alternative here are step-by-step instructions for installing Radicale 3.x on OpenBSD 7.6.

Update: Also works on OpenBSD 7.7

Limitations:

These instructions only cover the OpenBSD specific issues of installing Radicale itself. You may also want to set up TLS and/or a reverse proxy, authentication, etc. Please refer to the Radicale documentation, such as https://radicale.org/v3.html or other parts of this wiki, for these aspects of setting up the service.
At the original time of writing Radicale 3.3.0 was the latest version. Radicale 3.5.2 also seems to work fine. Other versions are untested.
Use at your own risk.

Prerequisites

A fresh installation of OpenBSD 7.6 or OpenBSD 7.7 is assumed.
The OpenBSD host needs to be able to access the Internet to install ports and to access the pip repository.
Sufficient disk space to install Python, the virtual Python environment and Radicale is assumed. (The needed space is not excessive, so in most cases this will be a non-issue.)
You will need access as root, either directly or by using doas(1) on the host. These instructions assume direct root access as indicated by the # prompt. A $ prompt indicates that no root access is required for the command.
A text editor of your choice or the capability to edit files elsewhere and transfer them to the host are also required. vi(1) and mg(1) are included in the OpenBSD base installation and other editors such as Emacs or nano are available as ports. (In theory you could get by without an editor. But that would involve complicated and tedious alternatives.) Note that text files follow the *NIX line ending convention, i.e. ending lines with a single LF (ASCII/UTF-8 0x0a, U+000a) character. The character encoding should be ASCII or UTF-8 (which are identical for anything described here).

These instructions may also work on OpenBSD 7.5 and on future versions. But this is untested.

Installing Radicale

Add the ports for Python and pip (unless they are already installed):
# pkg_add python py3-pip
Create a virtual Python environment to avoid mixing pkg_add(1) and pip managed code:
# python3 -m venv /usr/local/lib/radicale
[Optional] Update pip in the virtual Python environment to silence warnings when using pip:
# /usr/local/lib/radicale/bin/pip install --upgrade pip
Install Radicale into the virtual Python environment:
# /usr/local/lib/radicale/bin/pip install radicale
Create a user and group for running Radicale:
# useradd -g =uid -L daemon -c 'Radicale user' -s /sbin/nologin -u 672 -d /nonexistent _radicale
Note: This is the same user and group that is installed by the Radicale 2.x port. If you feel that it is too dangerous to reuse the same name and UID/GID then feel free to use different values, but make sure you adjust the following instructions accordingly.
Create a directory for the Radicale configuration:
# mkdir /etc/radicale
Create at least a minimal configuration file /etc/radicale/config to override the default storage location /var/lib/… which doesn't exist on OpenBSD:

[storage]
filesystem_folder = /var/db/radicale/collections

Of course you will probably want to add your own configuration settings to this file as well.

Create the storage location and set its owner/group to the user/group created above:
# install -o _radicale -g _radicale -d /var/db/radicale
Create an rc.d(8) service script for Radicale as /etc/rc.d/radicale3 and make it executable:

#!/bin/ksh
 
daemon='/usr/local/lib/radicale/bin/radicale'
daemon_user='_radicale'
daemon_logger='daemon.info'
 
. /etc/rc.d/rc.subr
 
pexp=".* ${daemon}.*"
rc_reload=NO
rc_configtest=NO
rc_bg=YES
 
rc_cmd $1

# chmod 755 /etc/rc.d/radicale3

[Optional] Enable the service to start at system boot:
# rcctl enable radicale3
Start the Radicale service:
# rcctl start radicale3

Logging

Radicale logs can be found in /var/log/daemon. You can configure syslogd(8) to place the logs into their own log file, e.g. by following these additional steps:

Add the following to the top of /etc/syslogd.conf:

!!radicale3
daemon.info						/var/log/radicale
!*

Create the log file:
# touch /var/log/radicale
Reload the syslogd(8) configuration:
# rcctl reload syslogd
[Optional] Set up log rotation for the Radicale log file by adding something like the following to /etc/newsyslog.conf:
/var/log/radicale 644 7 250 * Z

Note: The OpenBSD syslog(3) mechanism mangles UTF-8 characters outside the 7-bit ASCII range. It is unknown whether that would be an issue for Radicale?

Managing the service

FYI only (this is general OpenBSD knowledge, not specific to Radicale). See rcctl(8) for details.

Stop the service

# rcctl stop radicale3

Check the service

# rcctl check radicale3

# rcctl ls started

Restart the service/reload the configuration

# rcctl restart radicale3

Disable launching the service a system boot

# rcctl disable radicale3

Updating Radicale

Once installed as described above there may come a time when you want to update Radicale to the newest version.

Stop the Radicale service:
# rcctl stop radicale3
Update Radicale in the virtual Python environment:
# /usr/local/lib/radicale/bin/pip install --upgrade radicale
Make any required changes to the configuration if the new version requires any changes.
Start the Radicale service:
# rcctl start radicale3

Updates to Python (or to OpenBSD)

Whenever Python is updated (which often happens when OpenBSD is updated) the virtual Python environment does not automatically reflect all of these changes. (I think only changes of the x.x version are relevant, not the x.x.x minor updates. But I could be wrong.)

Updating the virtual Python environment essentially means creating a new one.

Note: This also updates Radicale to the newest version.

Stop the Radicale service:
# rcctl stop radicale3
[Optional] Make a backup of the existing virtual Python environment, e.g. by renaming it:
# mv /usr/local/lib/radicale /usr/local/lib/radicale-backup
Recreate the virtual Python environment as described above:
- Create a virtual Python environment to avoid mixing pkg_add(1) and pip managed code:
  # python3 -m venv /usr/local/lib/radicale
- [Optional] Update pip in the virtual Python environment to silence warnings when using pip:
  # /usr/local/lib/radicale/bin/pip install --upgrade pip
- Install Radicale into the virtual Python environment:
  # /usr/local/lib/radicale/bin/pip install radicale
Make any required changes to the configuration if the new version of Radicale requires any changes.
Start the Radicale service:
# rcctl start radicale3
[Optional] Remove the backup created in step 2 when everything is working as expected:
# rm -rf /usr/local/lib/radicale-backup

Other

Check which version of Radicale is installed:
$ /usr/local/lib/radicale/bin/pip show radicale