From Fedora Project Wiki

Hosting metadata for yum/DNF or Flatpak

Metadata for distribution tools and GNOME Software must be refreshed periodically, such as when new versions of packaged applications are released for consumption by users. In many cases, Linux distributions take care of the metadata extraction, generation, and hosting for these purposes. However, this section provides information on how to host your own metadata in case you need to do so.

Install helper utilities

Install the following software to help parse and generate the metadata needed for hosting:

$ sudo dnf install createrepo_c libappstream-glib-builder flatpak-builder 
 Generating yum repository metadata

Run these commands to create the initial metadata for source packages and the standard x86_64 architecture:

$ createrepo_c --no-database --simple-md-filenames SRPMS/
$ createrepo_c --no-database --simple-md-filenames x86_64/
Next, generate the AppStream XML using the appstream-builder tool:
$ appstream-builder				\
	--origin=yourcompanyname		\
	--basename=appstream			\
	--cache-dir=/tmp/asb-cache		\
	--enable-hidpi				\
	--max-threads=1				\
	--min-icon-size=32			\
	--output-dir=/tmp/asb-md		\
	--packages-dir=x86_64/			\
Scanning packages...
Processing packages...
Merging applications...
Writing /tmp/asb-md/appstream.xml.gz...
Writing /tmp/asb-md/appstream-icons.tar.gz...
Writing /tmp/asb-md/appstream-screenshots.tar...

The actual build output will depend on your compose server configuration. At this point you can also verify the application is visible in the yourcompanyname.xml.gz file.

Next, take the generated XML and the tarball of icons and add it to the repomd.xml master document, so that GNOME Software automatically downloads the content for searching:

$ modifyrepo_c					\
	--no-compress				\
	--simple-md-filenames			\
	/tmp/asb-md/appstream.xml.gz		\
$ modifyrepo_c					\
	--no-compress				\
	--simple-md-filenames			\
	/tmp/asb-md/appstream-icons.tar.gz	\

Deploying this metadata allows GNOME Software to add the application metadata the next time the repository is refreshed.

Hosting a DNF repository on Github

While Github isn't ideal for hosting DNF repositories, this method currently works:

Once you've created a local copy of your repository, create a new project on Github. Then use the follow commands to import your repository into Github.

$ cd ~/src/myrepository
$ git init
$ git add -A
$ git commit -a -m "first commit"
$ git remote add origin
$ git push -u origin master

Next, go to the Github web interface and browse down in the file tree until you find the file called repomd.xml, and click on it. You should now see a button in the Github interface called Raw. Click that to get the raw version of the XML file. In the URL bar of your browser you should see a URL like this:

Copy that URL, as you'll need it to create the .repo file that distributions and users use to reach your new repository.

Create a .repo file using this example as a template, and edit it to match your data:

name=Frobnicator 3D generator

For more information on this format, consult the repository options in the DNF configuration documentation.

Copy this file to /etc/yum.repos.d on your computer and load up GNOME Software. Click on the Updates button in GNOME Software, and then select the refresh button in the top left corner to ensure your database is up to date. You should then be able to search in GNOME software and find your new application. Generating Flatpak metadata

The Flatpak application packaging standard is another way to provide metadata for consumers. This guide assumes you are familiar with this standard, along with the manifest and basic build operations required. You can find extensive information on building Flatpaks and on hosting and signing flatpak repostories here.

Create an empty repository in a repo folder with this command:

$ ostree init --mode=archive-z2 --repo=repo

To tell flatpak-builder to import the end result of a build into this repository, pass the --repo option to use the folder you created:

$ flatpak-builder --verbose --force-clean \
        --repo=repo --gpg-homedir=gpg --gpg-sign=$GPG_KEY \
	recipes flatpak/org.example.Frobnicator.json

To generate appstream branches and static deltas in this repository use this command:

$ flatpak build-update-repo --generate-static-deltas \
        --gpg-homedir=gpg --gpg-sign=$GPG_KEY repo

Note that both of these commands take a --gpg-sign argument. Flatpak uses GPG as a means to ensure that the repository can be trusted, so you should sign your public repositories.

To make your application and its Flatpak repository available to users is to publish a flatpakref file:

[Flatpak Ref]
Comment=GNOME loves to Frobnicate

Hosting a Flatpak repository on Github

Github isn't ideal for hosting Flatpak repositories, but this method currently works.

Once you create a local copy of your repository, create a new project on Github, enable Github pages for the project and point it at the master branch.

Next, import your repository into Github.

$ git remote add origin
$ git push -u origin master

Now you should be able to refer to your repo with a URL as shown in the flatpakrepo example above.

A note on third party repositories

For more information on inclusion in Fedora as a third party software repository, consult with the Fedora Workstation working group.