Please create instructions how to build the projects locally using .gitlab-ci

I see a lot of articles about how to build gnome components using some build systems and stuff. But I think there should be a way to just use the gitlab ci for local building. Instead of configuring and installing the build system to the system you can probably use gitlab ci, like described here: https://stackoverflow.com/a/65920577/7415288

I want to build gnome-control-center using gitlab ci config.

marat@marat-pc:~/Desktop/gnome-control-center$ docker run -v $PWD:$PWD -w $PWD -v /var/run/docker.sock:/var/run/docker.sock gitlab/gitlab-runner exec docker build 
Runtime platform                                    arch=amd64 os=linux pid=7 revision=7a6612da version=13.12.0
Running with gitlab-runner 13.12.0 (7a6612da)
Preparing the "docker" executor
Using Docker executor with image /gnome/gnome-control-center/fedora/rawhide:latest ...
Pulling docker image /gnome/gnome-control-center/fedora/rawhide:latest ...
WARNING: Failed to pull image with policy "always": invalid reference format (manager.go:205:0s)
ERROR: Preparation failed: failed to pull image "/gnome/gnome-control-center/fedora/rawhide:latest" with specified policies [always]: invalid reference format (manager.go:205:0s)
Will be retried in 3s ...
Using Docker executor with image /gnome/gnome-control-center/fedora/rawhide:latest ...
Pulling docker image /gnome/gnome-control-center/fedora/rawhide:latest ...
WARNING: Failed to pull image with policy "always": invalid reference format (manager.go:205:0s)
ERROR: Preparation failed: failed to pull image "/gnome/gnome-control-center/fedora/rawhide:latest" with specified policies [always]: invalid reference format (manager.go:205:0s)
Will be retried in 3s ...
Using Docker executor with image /gnome/gnome-control-center/fedora/rawhide:latest ...
Pulling docker image /gnome/gnome-control-center/fedora/rawhide:latest ...
WARNING: Failed to pull image with policy "always": invalid reference format (manager.go:205:0s)
ERROR: Preparation failed: failed to pull image "/gnome/gnome-control-center/fedora/rawhide:latest" with specified policies [always]: invalid reference format (manager.go:205:0s)
Will be retried in 3s ...
ERROR: Job failed (system failure): failed to pull image "/gnome/gnome-control-center/fedora/rawhide:latest" with specified policies [always]: invalid reference format (manager.go:205:0s)
FATAL: failed to pull image "/gnome/gnome-control-center/fedora/rawhide:latest" with specified policies [always]: invalid reference format (manager.go:205:0s) 
marat@marat-pc:~/Desktop/gnome-control-center

But as you can see I gen an error. I think the way of building the components using .gitlab-ci should become more popularized. Don’t you think?

GNOME Control Center already has a CI pipeline. You cannot just take the CI pipeline off of GitLab and run it yourself, though.

If you want to contribute to GNOME Control Center, using Docker to build it is not a great plan, either. You could try using the Flatpak manifest and GNOME Builder, but remember that the Control Center is not a generic application: it is a core system component, and it is used to talk to various system services.