As part of my work on the Barrier project, we needed a way to build it with the [Qt installer]from an online CI/CD service. On some platforms, such as Appveyor, Qt may be preinstalled. But on some other platforms such as Azure Pipelines, Qt may not be pre-installed. Nor on Travis. Nor on CircleCI. For Linux and macOS, there is a saving grace. The Qt libraries can be installed headlessly from their operating system repositories such as apt or brew. But this luxury does not exist as well on Windows. While Chocolatey does offer some Qt packages, they tend to ancient or non-official.

There is a toolkit called CuteCI that let you use the Qt Installer and script the GUI headlessly. It’s janky and big though. Additionally, to pin versions, you must download 3 to 5 GB of Qt Installer to install a pinned version of Qt.

So, I found this: https://lnj.gitlab.io/post/qli-installer/

Apparently it’s possible to mimic the Qt Installer from a Python script.

To save it from possible bit-rot, I forked it to GitHub. I added parallel downloading, Windows support, and a CI system. I pushed Azure-Pipelines and each commit could cause 100 jobs to run. Across all the various platforms. Azure Pipelines did not break a sweat.

CuteCI is still extremely useful if you must use the official installer with official support. But the speeds with my fork were insane. It would normally take many minutes to install Qt with CuteCI. My QLI-Installer fork? 10 or 20 seconds.

But it turns out there’s an even better installer than mine!

https://github.com/miurahr/aqtinstall/

aqtinstall

• Classy reusable Python structure
• On PyPi. You can do pip install aqtinstall and install aqtinstall for immediate use.

This is also another fork of qli-installer. The CI system was a in a bit of a sorry state though. So I contributed matrix generated jobs to test aqtinstall across Mac, Windows, and Linux. @miurahr was able to dial down the installation and testing madness too and ramp it up in some places. Actual Qt applications are built to test if aqtinstall work. Additionally, there was the insight that mobile platforms generally always require the latest Qt version.

So, if you want a fast and lightweight headless Qt installer that installs from Qt Mirrors and is continually tested, use aqtinstall!