Packaging Tutorial

Creating a Flatpak of an application that is already packaged in Fedora involves two steps. First you need to create a module for the application. This module will be used to rebuild the application RPM and RPMs. Then you need to create a container out of the module. In the Fedora context, flatpaks are just another form of container, and are handled very similar to the Docker containers used for server applications.

Just as for packages, the instructions for building modules and containers are stored in git on src.fedoraproject.org and builds are coordinated by koji.fedoraproject.org. The flatpak for a an application can be found on src.fedoraprojec.org in the repository modules/<application>; this git repository contains two files: <application>.yaml, which defines the contents of the module, and container.yaml, which defines how the module is turned into a Flatpak container.

Setup

Install the necessary tools:

$ sudo dnf install flatpak-module-tools fedmod

Make sure that your user is in the mock group (both local module builds and local container builds use mock).

$ sudo usermod -a -G mock $USER

(You may need to log out and log back in.)

Creating <application>.yaml and container.yaml

$ mkdir feedreader && cd feedreader
$ fedmod fetch-metadata
$ fedmod rpm2flatpak feedreader

This generates templates versions of the two files. First we’ll look at the module definition file:

feedreader.yaml
---
document: modulemd
version: 2
data:
  summary: RSS desktop client (1)
  description: >- (1)
    FeedReader is a modern desktop application designed to complement existing web-based
    RSS accounts. It combines all the advantages of web based services like synchronization
    across all your devices with everything you expect from a modern desktop application.
  license:
    module:
    - MIT
  dependencies:
  - buildrequires:
      flatpak-runtime: [f29]
    requires:
      flatpak-runtime: [f29]
  profiles: (2)
    default:
      rpms:
      - feedreader
  api: (3)
    rpms:
    - feedreader
  components:
    rpms:
      feedreader: (4)
        rationale: Package in api
        buildorder: 10
      gnome-online-accounts: (5)
        rationale: Runtime dependencies
      libgee: (5)
        rationale: Runtime dependencies
      libpeas: (5)
        rationale: Runtime dependencies
...
1 Source and description come from RPM metadata
2 The default profile lists RPMs to be included along with their dependencies
3 The API section defines the public API for the module. It can be ignored.
4 The main package for the application
5 Further source rpms that will be rebuilt for bundling

This could be used as-is. For more complex cases, it may be necessary to add additional buildorder: keys so that the bundle dependencies build in the correct order.

Then we’ll look at the container.yaml file. This will require more editing. Since feedreader can be found on Flathub, we can use flatpak-builder manifest as a source for the application ID and permissions.

container.yaml (as generated)
compose:
    modules:
        - feedreader:master
flatpak:
    # Derived from the project's domain name
    id: org.example.MyApp
    branch: stable
    # Binary to execute to run the app
    command: feedreader
    tags: []
    # Not sandboxed. See 'man flatpak-build-finish'
    finish-args: >
        --filesystem=host
        --share=ipc
        --socket=x11
        --socket=wayland
        --socket=session-bus
container.yaml (edited)
compose:
    modules:
        - feedreader:master
flatpak:
    id: org.gnome.FeedReader (1)
    branch: stable
    command: feedreader
    tags: []
    finish-args: > (2)
        --share=ipc
        --share=network
        --socket=fallback-x11
        --socket=wayland
        --socket=pulseaudio
        --device=dri
        --filesystem=xdg-run/dconf --filesystem=~/.config/dconf:ro
        --talk-name=ca.desrt.dconf --env=DCONF_USER_CONFIG_DIR=.config/dconf
        --own-name=org.gnome.FeedReader.ArticleView
        --talk-name=org.gnome.OnlineAccounts
        --talk-name=org.freedesktop.Notifications
        --talk-name=org.freedesktop.secrets
1 Changed to application ID to match Flathub
2 Adjust finish-args - copy from Flathub flatpak-builder manifest. See finish-args for more details

Doing a local build

$ flatpak-module local-build --install

This is a shortcut for three steps:

$ flatpak-module build-module
$ flatpak-module build-container --from-local
$ flatpak-module install <application>-master-<version>.oci.tar.gz

If building the module succeeds but building the container fails, and you need to change container.yaml and try again, you can do:

$ flatpak-module build-container --from-local --install

Testing

If installation succeeded, you can now do:

$ flatpak run org.gnome.FeedReader

To try it out.

src.fedoraproject.org request

Please request a new module as follows:

$ fedpkg request-repo --namespace=modules <application>

For now: When that ticket has been handled, file an issue in https://pagure.io/releng as follows:

Please add <application> to the f29-flatpak tag.

   $ koji add-pkg --owner=releng f29-flatpak <application>

Importing your module content

Once your releng issue has been resolved

$ mv <application> <application>.old
$ fedpkg clone modules/<application>
$ cd <application>
$ cp ../application.old/{<application>.yaml,container.yaml} .
$ git add <application>.yaml container.yaml
$ git commit -m “Initial import”
$ git push origin master

Building in Koji

First build the module

$ fedpkg module-build

If that completes successfully, you can then do:

$ fedpkg flatpak-build

Testing the build

Go to the Koji page of the successful Flatpak build, find the download link for the Image Archive and paste that into the command line:

$ flatpak-module install --koji <application>:master

Creating an update

Find the NVR of your Flatpak build - if you don’t have it in your terminal scrollback go to https://koji.fedoraproject.org/ and search in "Packages" for the application name. The build ID for the Flatpak build will be something like: myapplication-20b180601144429.2.

Go to https://bodhi.fedoraproject.org/updates/new and enter the flatpak NVR under Candidate Builds (ignore “Packages”). Enter text under “Update notes” like “Initial Flatpak of <application>”, and hit <Submit>.