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+Title: Using appstream with isenkram to install hardware related packages in Debian
+Tags: english, debian, isenkram
+Date: 2015-12-20 12:20
+
+<p>Around three years ago, I created
+<a href="http://packages.qa.debian.org/isenkram">the isenkram
+system</a> 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.</p>
+
+<p>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,
+<a href="http://www.freedesktop.org/software/appstream/docs/">the
+appstream system</a> 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.</p>
+
+<p>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
+<a href="https://appstream.debian.org/html/sid/main/metainfo/pymissile.html">metadata
+in pymissile</a>.  I added a file debian/pymissile.metainfo.xml with
+this content:</p>
+
+<blockquote><pre>
+&lt;?xml version="1.0" encoding="UTF-8"?&gt;
+&lt;component&gt;
+  &lt;id&gt;pymissile&lt;/id&gt;
+  &lt;metadata_license&gt;MIT&lt;/metadata_license&gt;
+  &lt;name&gt;pymissile&lt;/name&gt;
+  &lt;summary&gt;Control original Striker USB Missile Launcher&lt;/summary&gt;
+  &lt;description&gt;
+    &lt;p&gt;
+      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.
+    &lt;/p&gt;
+  &lt;/description&gt;
+  &lt;provides&gt;
+    &lt;modalias&gt;usb:v1130p0202d*&lt;/modalias&gt;
+  &lt;/provides&gt;
+&lt;/component&gt;
+</pre></blockquote>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<p>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:</p>
+
+<blockquote><pre>
+debian/pymissile.metainfo.xml usr/share/appdata
+</pre></blockquote>
+
+<p>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.</p>
+
+<p>Details of the modalias field in appstream is available from the 
+<a href="https://wiki.debian.org/DEP-11">DEP-11</a> proposal.</p>
+
+<p>To locate the modalias values of all hardware present in a machine,
+try running this command on the command line:</p>
+
+<blockquote><pre>
+cat $(find /sys/devices/|grep modalias)
+</pre></blockquote>
+
+<p>To learn more about the isenkram system, please check out
+<a href="http://people.skolelinux.org/pere/blog/tags/isenkram/">my
+blog posts tagged isenkram</a>.</p>