Deprecated: This document has been superseded by Using external metadata
Some of the values required by the snapcraft.yaml file might be already provided by other metadata sources available in the upstream project.
Instead of duplicating this information, you can declare that a snapcraft part
must parse the metadata file from the source, and adopt that parsed
information. For example, the following snapcraft.yaml will parse the file
called metadata-file and try to extract from it the version, summary and
description for the snap.
name: my-snap-name
adopt-info: part-with-metadata
parts:
part-with-metadata:
plugin: dump
parse-info: [metadata-file]
Metadata sources
Currently, the only supported source of metadata is appstream.
Appstream
Appstream is a standard
for metadata of software components. It can provide the summary,
description and icon for the snap, and the desktop files for the
apps.
Let’s say we have an upstream project with the following appstream file in
sampleapp.metainfo.xml:
<?xml version="1.0" encoding="UTF-8"?>
<component type="desktop-application">
<id>com.example.sampleapp</id>
<summary>Single-line elevator pitch for your amazing application</summary>
<description>
This is applications's description. A paragraph or two to tell the
most important story about it.
</description>
<icon type="local">assets/icon.png</icon>
<launchable type="desktop-id">
com.example.sampleapp.desktop
</launchable>
</component>
Then you can adopt this info into your snapcraft.yaml like this:
name: sampleapp-name
adopt-info: sampleapp
apps:
sampleapp:
command: sampleapp
common-id: com.example.sampleapp
parts:
sampleapp:
plugin: dump
source: http://github.com/example/sampleapp.git
parse-info: [sampleapp.metainfo.xml]
The resulting snap will take the summary and description from the appstream file and it will use the referred icon and desktop files.
Note that appstream doesn’t use a path to declare the desktop file. It uses
a Desktop File ID.
To know which appstream desktop-id corresponds to your app, you must declare
the common-id of the app in the snapcraft.yaml. snapcraft will search for a
parsed appstream file with the same component id and extract the desktop-id.
Then it will search for the desktop file in the directories usr/local/share
and usr/share relative to the part source, following the Desktop File ID
rules.