flatpak-builder/doc/flatpak-metadata.xml

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<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<refentry id="flatpak-metadata">
<refentryinfo>
<title>flatpak metadata</title>
<productname>flatpak</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Alexander</firstname>
<surname>Larsson</surname>
<email>alexl@redhat.com</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>flatpak metadata</refentrytitle>
<manvolnum>5</manvolnum>
</refmeta>
<refnamediv>
<refname>flatpak-metadata</refname>
<refpurpose>Information about an application or runtime</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<para>
Flatpak uses metadata files to describe applications and runtimes.
The <filename>metadata</filename> file for a deployed application or
runtime is placed in the toplevel deploy directory. For example, the
metadata for the locally installed application org.gnome.Calculator
is in
<filename>~/.local/share/flatpak/app/org.gnome.Calculator/current/active/metadata</filename>.
</para>
<para>
Most aspects of the metadata configuration can be overridden when
launching applications, either temporarily via options of the flatpak
run command, or permanently with the flatpak override command.
</para>
<para>
A metadata file describing the effective configuration is available
inside the running sandbox at <filename>/.flatpak-info</filename>.
For compatibility with older Flatpak versions,
<filename>/run/user/$UID/flatpak-info</filename> is a symbolic
link to the same file.
</para>
</refsect1>
<refsect1>
<title>File format</title>
<para>
The metadata file is using the same .ini file format that is used for
systemd unit files or application .desktop files.
</para>
<refsect2>
<title>[Application] or [Runtime]</title>
<para>
Metadata for applications starts with an [Application] group,
metadata for runtimes with a [Runtime] group.
</para>
<para>
The following keys can be present in these groups:
</para>
<variablelist>
<varlistentry>
<term><option>name</option> (string)</term>
<listitem><para>The name of the application or runtime. This key is mandatory.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>runtime</option> (string)</term>
<listitem><para>The fully qualified name of the runtime that is used by the application. This key is mandatory for applications.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>sdk</option> (string)</term>
<listitem><para>The fully qualified name of the sdk that matches the runtime.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>command</option> (string)</term>
<listitem><para>The command to run. Only relevant for applications.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>required-flatpak</option> (string)</term>
<listitem><para>
The required version of Flatpak to run this application
or runtime.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>tags</option> (string list)</term>
<listitem><para>
Tags to include in AppStream XML.
<!-- TODO: what are these tags for? What should they
be? -->
</para></listitem>
</varlistentry>
</variablelist>
</refsect2>
<refsect2>
<title>[Context]</title>
<para>
This group determines various system resources that may be shared
with the application when it is run in a flatpak sandbox.
</para>
<para>
All keys in this group (and the group itself) are optional.
</para>
<variablelist>
<varlistentry>
<term><option>shared</option> (list)</term>
<listitem><para>
List of subsystems to share with the host system.
Possible subsystems: network, ipc.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>sockets</option> (list)</term>
<listitem><para>
List of well-known sockets to make available in the sandbox.
Possible sockets: x11, wayland, pulseaudio, session-bus, system-bus.
When making a socket available, flatpak also sets
well-known environment variables like DISPLAY or
DBUS_SYSTEM_BUS_ADDRESS to let the application
find sockets that are not in a fixed location.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>devices</option> (list)</term>
<listitem><para>
List of devices to make available in the sandbox.
Possible values: dri, kvm, all.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>filesystems</option> (list)</term>
<listitem><para>
List of filesystem subsets to make available to the
application. Possible values: home, host, xdg-desktop,
xdg-documents, xdg-download xdg-music, xdg-pictures,
xdg-public-share, xdg-templates, xdg-videos, xdg-run,
xdg-config, xdg-cache, xdg-data,
an absolute path, or a homedir-relative path like
~/dir or paths relative to the xdg dirs, like
xdg-download/subdir. The xdg-* arguments can also
specify a subdirectory, such as xdg-pictures/screenshots.
Each entry can have a suffix of
:ro, :rw or :create to indicate if the path should be shared
read-only, read-write or read-write + create if needed
(default is read-write).
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>persistent</option> (list)</term>
<listitem><para>
List of homedir-relative paths to make available at
the corresponding path in the per-application home directory,
allowing the locations to be used for persistent data when
the application does not have access to the real homedir.
For instance making ".myapp" persistent would make "~/.myapp"
in the sandbox a bind mount to "~/.var/app/org.my.App/.myapp",
thus allowing an unmodified application to save data in
the per-application location.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>features</option> (list)</term>
<listitem><para>
List of features available or unavailable to the
application, currently from the following list:
devel, multiarch.
A feature can be prefixed with ! to indicate the absence
of that feature, for example !devel if development and
debugging are not allowed.
</para></listitem>
</varlistentry>
</variablelist>
</refsect2>
<refsect2>
<title>[Instance]</title>
<para>
This group only appears in <filename>/.flatpak-info</filename>
for a running app, and not in the metadata files written by
application authors. It is filled in by Flatpak itself.
</para>
<variablelist>
<varlistentry>
<term><option>app-path</option> (string)</term>
<listitem><para>
The absolute path on the host system of the app's
app files, as mounted at <filename>/app</filename>
inside the container
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>branch</option> (string)</term>
<listitem><para>
The branch of the app, for example
<literal>stable</literal>
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>flatpak-version</option> (string)</term>
<listitem><para>
The version number of the Flatpak version that ran
this app
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>runtime-path</option> (string)</term>
<listitem><para>
The absolute path on the host system of the app's
runtime files, as mounted at <filename>/usr</filename>
inside the container
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>session-bus-proxy</option> (boolean)</term>
<listitem><para>
True if this app cannot access the D-Bus session bus
directly (either it goes via a proxy, or it cannot
access the session bus at all)
<!-- TODO: Those semantics are weird, are they
intended? -->
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>system-bus-proxy</option> (boolean)</term>
<listitem><para>
True if this app cannot access the D-Bus system bus
directly (either it goes via a proxy, or it cannot
access the system bus at all)
<!-- TODO: Those semantics are weird, are they
intended? -->
</para></listitem>
</varlistentry>
</variablelist>
</refsect2>
<refsect2>
<title>[Session Bus Policy]</title>
<para>
If the <option>sockets</option> key is not allowing full access
to the D-Bus session bus, then flatpak provides filtered access.
</para>
<para>
The default policy for the session bus only allows the
application to own its own application ID and
subnames. For instance if the app is called
"org.my.App", it can only own "org.my.App" and
"org.my.App.*". Its also only allowed to talk to the
bus itself (org.freedesktop.DBus) and the portal APIs
APIs (bus names of the form org.freedesktop.portal.*).
</para>
<para>
Additionally the app is always allowed to reply to
messages sent to it, and emit broadcast signals (but
these will not reach other sandboxed apps unless they
are allowed to talk to your app.
</para>
<para>
If the [Session Bus Policy] group is present, it provides
policy for session bus access.
</para>
<para>
Each key in this group has the form of a D-Bus bus name or
prefix thereof, for example <option>org.gnome.SessionManager</option>
or <option>org.freedesktop.portal.*</option>
</para>
<para>
The possible values for entry are, in increasing order or
access:
</para>
<variablelist>
<varlistentry>
<term><option>none</option></term>
<listitem><para>
The bus name or names in question is invisible to the application.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>see</option></term>
<listitem><para>
The bus name or names can be enumerated by the application.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>talk</option></term>
<listitem><para>
The application can send messages/ and receive replies and signals from the bus name or names.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>own</option></term>
<listitem><para>
The application can own the bus name or names (as well as all the above).
</para></listitem>
</varlistentry>
</variablelist>
</refsect2>
<refsect2>
<title>[System Bus Policy]</title>
<para>
If the <option>sockets</option> key is not allowing full access
to the D-Bus system bus, then flatpak does not make the system
bus available unless the [System Bus Policy] group is present
and provides a policy for filtered access.
</para>
<para>
Entries in this group have the same form as for the [Session Bus Policy] group.
However, the app has no permissions by default.
</para>
</refsect2>
<refsect2>
<title>[Environment]</title>
<para>
The [Environment] group specifies environment variables to set
when running the application.
</para>
<para>
Entries in this group have the form <option>VAR=VALUE</option>
where <option>VAR</option> is the name of an environment variable
to set.
</para>
</refsect2>
<refsect2>
<title>[Extension NAME]</title>
<para>
Runtimes and applications can define extension points, which allow
optional, additional runtimes to be mounted at a specified location
inside the sandbox when they are present on the system. Typical uses
for extension points include translations for applications, or debuginfo
for sdks. The name of the extension point is specified as part of the
group heading.
</para>
<variablelist>
<varlistentry>
<term><option>directory</option> (string)</term>
<listitem><para>
The relative path at which the extension will be mounted in
the sandbox. If the extension point is for an application, the
path is relative to <filename>/app</filename>, otherwise
it is relative to <filename>/usr</filename>. This key
is mandatory.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>version</option> (string)</term>
<listitem><para>
The branch to use when looking for the extension. If this is
not specified, it defaults to the branch of the application or
runtime that the extension point is for.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>versions</option> (string)</term>
<listitem><para>
The branches to use when looking for the extension. If this is
not specified, it defaults to the branch of the application or
runtime that the extension point is for.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>add-ld-path</option> (string)</term>
<listitem><para>
A path relative to the extension point directory that will be appended
to LD_LIBRARY_PATH.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>merge-dirs</option> (string)</term>
<listitem><para>
A list of relative paths of directories below the extension point directory
that will be merged.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>download-if</option> (string)</term>
<listitem><para>
A condition that must be true for the extension to be auto-downloaded.
The only currently recognized value is active-gl-driver, which is true
if the name of the active GL driver matches the extension point basename.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>enable-if</option> (string)</term>
<listitem><para>
A condition that must be true for the extension to be enabled.
The only currently recognized value is active-gl-driver, which is true
if the name of the active GL driver matches the extension point basename.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>subdirectory-suffix</option> (string)</term>
<listitem><para>
A suffix that gets appended to the directory name. This is very
useful when the extension point naming scheme is "reversed". For example,
an extension point for GTK+ themes would be /usr/share/themes/$NAME/gtk-3.0,
which could be achieved using subdirectory-suffix=gtk-3.0.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>subdirectories</option> (boolean)</term>
<listitem><para>
If this key is set to true, then flatpak will look for
extensions whose name is a prefix of the extension point name, and
mount them at the corresponding name below the subdirectory.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>no-autodownload</option> (boolean)</term>
<listitem><para>
Whether to automatically download extensions matching this extension
point when updating or installing a 'related' application or runtime.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>autodelete</option> (boolean)</term>
<listitem><para>
Whether to automatically delete extensions matching this extension
point when deleting a 'related' application or runtime.
</para></listitem>
</varlistentry>
<!-- FIXME: Uncomment this when enable-p2p is enabled unconditionally.
<varlistentry>
<term><option>collection-id</option> (string)</term>
<listitem><para>
The ID of the collection that this extension point belongs to. If this
is unspecified, it defaults to the collection ID of the application
or runtime that the extension point is for.
Currently, extension points must be in the same collection as the
application or runtime that they are for.
</para></listitem>
</varlistentry>
-->
</variablelist>
</refsect2>
<refsect2>
<title>[ExtensionOf]</title>
<para>
This optional group may be present if the runtime is an extension.
</para>
<variablelist>
<varlistentry>
<term><option>ref</option> (string)</term>
<listitem><para>
The ref of the runtime or application that this extension
belongs to.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>priority</option> (integer)</term>
<listitem><para>
The priority to give this extension when looking for the
best match. Default is 0.
</para></listitem>
</varlistentry>
</variablelist>
</refsect2>
<refsect2>
<title>[Extra Data]</title>
<para>
This optional group may be present if the runtime or application uses
extra data that gets downloaded separately. The data in this group
gets merged into the repository summary, with the xa.extra-data-sources
key.
</para>
<para>
If multiple extra data sources are present, their uri, size and checksum
keys are grouped together by using the same suffix. If only one extra
data source is present, the suffix can be omitted.
</para>
<variablelist>
<varlistentry>
<term><option>NoRuntime</option> (boolean)</term>
<listitem><para>
Whether to mount the runtime while running the /app/bin/apply_extra
script. Defaults to true, i.e. not mounting the runtime.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>uriX</option> (string)</term>
<listitem><para>
The uri for extra data source X. The only supported uri schemes are
http and https.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>sizeX</option> (integer)</term>
<listitem><para>
The size for extra data source X.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>checksumX</option> (string)</term>
<listitem><para>
The sha256 sum for extra data source X.
</para></listitem>
</varlistentry>
</variablelist>
</refsect2>
<refsect2>
<title>[Policy SUBSYSTEM]</title>
<para>
Subsystems can define their own policies to be placed in a group
whose name has this form. Their values are treated as lists,
in which items can have their meaning negated by prepending !
to the value. They are not otherwise parsed by Flatpak.
<!-- TODO: More information would be nice -->
</para>
</refsect2>
</refsect1>
<refsect1>
<title>Example</title>
<programlisting>
[Application]
name=org.gnome.Calculator
runtime=org.gnome.Platform/x86_64/3.20
sdk=org.gnome.Sdk/x86_64/3.20
command=gnome-calculator
[Context]
shared=network;ipc;
sockets=x11;wayland;
filesystems=xdg-run/dconf;~/.config/dconf:ro;
[Session Bus Policy]
ca.desrt.dconf=talk
[Environment]
DCONF_USER_CONFIG_DIR=.config/dconf
[Extension org.gnome.Calculator.Locale]
directory=share/runtime/locale
subdirectories=true
[Extension org.gnome.Calculator.Debug]
directory=lib/debug
</programlisting>
</refsect1>
<refsect1>
<title>See also</title>
<para>
<citerefentry><refentrytitle>flatpak</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>flatpak-run</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>flatpak-override</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>