The input to
flatpak-builder is a JSON or YAML file that describes the
parameters for building an application, as well as instructions for each of
the modules that are to be built. This file is called the manifest.
This page provides information and guidance on how to use manifests, including an explanation of the most common parameters that can be specified. It is recommended to have followed the Building your first Flatpak tutorial before reading this section, and to be familiar with Flatpak Builder.
Manifest files should be named using the application ID. For example, the
manifest file for GNOME Dictionary is named
page uses this manifest file for all its examples.
A complete list of all the properties that can be specified in manifest files
can be found in the Flatpak Builder Command Reference, as well as the
flatpak-manifest man page.
Each manifest file should specify basic information about the application that
is to be built, including the
command parameters. These properties are typically specified
at the beginning of the file.
For example, the GNOME Dictionary manifest includes:
app-id: org.gnome.Dictionary runtime: org.gnome.Platform runtime-version: '3.36' sdk: org.gnome.Sdk command: gnome-dictionary
Specifying a runtime and runtime version allows that the runtime that is needed by your application to be automatically installed on users’ systems.
Exports are application files that are made available to the host, and include
things like the application’s
.desktop file and icon.
The names of files that are exported by a Flatpak must be prefixed using the
application ID, such as
org.gnome.Dictionary.desktop. The best way to
do this is to rename these files directly in the application’s source.
If renaming exported files to use the application ID is not possible,
flatpak-builder allows them to be renamed as part of the build
process. This can be done by specifying one of the following properties in
rename-icon- rename the application icon
rename-desktop-file- rename the
rename-appdata-file- rename the AppData file
Each of these properties accepts the name of the source file to be
flatpak-builder then automatically renames the file to match
the application ID. Note that this renaming method can introduce internal
naming conflicts, and that renaming files in tree is therefore the most
Applications that are run with Flatpak have extremely limited access to the host environment by default, but applications require access to resources outside of their sandbox in order to be useful. Finishing is the build stage where the application’s sandbox permissions are specified, in order to give access to these resources.
The finishing manifest section uses the
finish-args property, which can
be seen in the Dictionary manifest file:
finish-args: # X11 + XShm access - --share=ipc - --socket=x11 # Wayland access - --socket=wayland # Needs to talk to the network: - --share=network # Needs to save files locally - --filesystem=xdg-documents - --metadata=X-DConf=migrate-path=/org/gnome/dictionary/
If you’re wondering about the last finish arg, see this blog post.
The cleanup property can be used to remove files produced by the build process that are not wanted as part of the application, such as headers or developer documentation. Two properties in the manifest file are used for this.
First, a list of filename patterns can be included:
cleanup: - '/include' - '/bin/foo-*' - '*.a'
The second cleanup property is a list of commands that are run during the cleanup phase:
cleanup-commands: - 'sed s/foo/bar/ /bin/app.sh'
Cleanup properties can be set on a per-module basis, in which case only filenames that were created by that particular module will be matched.
The module list specifies each of the modules that are to be built as part of the build process. One of these modules is the application itself, and other modules are dependencies and libraries that are bundled as part of the Flatpak. While simple applications may only specify one or two modules, and therefore have short modules sections, some applications can bundle numerous modules and therefore have lengthy modules sections.
GNOME Dictionary’s modules section is short, since it just contains the application itself, and looks like:
modules: - name: gnome-dictionary buildsystem: meson config-opts: - -Dbuild_man=false sources: - type: archive url: https://download.gnome.org/sources/gnome-dictionary/3.26/gnome-dictionary-3.26.1.tar.xz sha256: 16b8bc248dcf68987826d5e39234b1bb7fd24a2607fcdbf4258fde88f012f300 - type: patch path: appdata_oars.patch
As can be seen, each listed module has a
name (which can be freely
assigned) and a list of
sources. Each source has a
type, and available
git- Git repositories
bzr- Bazaar repositories
file- local file (these are copied into the source directory)
dir- local directory (these are copied into the source directory)
script- an array of shell commands (these are put in a shellscript file)
shell- an array of shell commands that are run during source extraction
patch- a patch (are applied to the source directory)
extra-data- data that can be downloaded at install time; this can include archive or package files
Different properties are available for each source type, which are listed in the Flatpak Builder Command Reference.
A complete manifest for GNOME Dictionary built from Git. It is also possible to browse all the manifests hosted by Flathub.