Around three years ago, I created the isenkram system to get a more practical solution in Debian for handing hardware related packages. A GUI system in the isenkram package will present a pop-up dialog when some hardware dongle supported by relevant packages in Debian is inserted into the machine. The same lookup mechanism to detect packages is available as command line tools in the isenkram-cli package. In addition to mapping hardware, it will also map kernel firmware files to packages and make it easy to install needed firmware packages automatically. The key for this system to work is a good way to map hardware to packages, in other words, allow packages to announce what hardware they will work with.
I started by providing data files in the isenkram source, and adding code to download the latest version of these data files at run time, to ensure every user had the most up to date mapping available. I also added support for storing the mapping in the Packages file in the apt repositories, but did not push this approach because while I was trying to figure out how to best store hardware/package mappings, the appstream system was announced. I got in touch and suggested to add the hardware mapping into that data set to be able to use appstream as a data source, and this was accepted at least for the Debian version of appstream.
A few days ago using appstream in Debian for this became possible, and today I uploaded a new version 0.20 of isenkram adding support for appstream as a data source for mapping hardware to packages. The only package so far using appstream to announce its hardware support is my pymissile package. I got help from Matthias Klumpp with figuring out how do add the required metadata in pymissile. I added a file debian/pymissile.metainfo.xml with this content:
<?xml version="1.0" encoding="UTF-8"?>
<component>
<id>pymissile</id>
<metadata_license>MIT</metadata_license>
<name>pymissile</name>
<summary>Control original Striker USB Missile Launcher</summary>
<description>
<p>
Pymissile provides a curses interface to control an original
Marks and Spencer / Striker USB Missile Launcher, as well as a
motion control script to allow a webcamera to control the
launcher.
</p>
</description>
<provides>
<modalias>usb:v1130p0202d*</modalias>
</provides>
</component>
The key for isenkram is the component/provides/modalias value, which is a glob style match rule for hardware specific strings (modalias strings) provided by the Linux kernel. In this case, it will map to all USB devices with vendor code 1130 and product code 0202.
Note, it is important that the license of all the metadata files are compatible to have permissions to aggregate them into archive wide appstream files. Matthias suggested to use MIT or BSD licenses for these files. A challenge is figuring out a good id for the data, as it is supposed to be globally unique and shared across distributions (in other words, best to coordinate with upstream what to use). But it can be changed later or, so we went with the package name as upstream for this project is dormant.
To get the metadata file installed in the correct location for the mirror update scripts to pick it up and include its content the appstream data source, the file must be installed in the binary package under /usr/share/appdata/. I did this by adding the following line to debian/pymissile.install:
debian/pymissile.metainfo.xml usr/share/appdata
With that in place, the command line tool isenkram-lookup will list all packages useful on the current computer automatically, and the GUI pop-up handler will propose to install the package not already installed if a hardware dongle is inserted into the machine in question.
Details of the modalias field in appstream is available from the DEP-11 proposal.
To locate the modalias values of all hardware present in a machine, try running this command on the command line:
cat $(find /sys/devices/|grep modalias)
To learn more about the isenkram system, please check out my blog posts tagged isenkram.