8 Combining ERB templates and scripts #
Section 4.31.1, “Pre-scripts” already describes how to use a
pre-script to modify the current profile. In a nutshell, if the script
creates a /tmp/profile/modified.xml file, AutoYaST imports
that profile and forgets about the initial one.
This is a pretty flexible approach and the only limitation is that you need to rely on the languages and libraries that are available in the installation media.
8.1 Embedding ERB in your scripts #
Unlike with rules, it is possible to combine ERB templates with scripts. AutoYaST will evaluate any ERB tag that you include in your script before running it. This behavior only applies to the scripts defined inside the profile and not to the external ones.
The script in the example below downloads a profile whose name is based on
the MAC address. Saving the file as
/tmp/profile/modified.xml will cause AutoYaST to load and
use the downloaded profile.
<scripts>
<pre-scripts config:type="list">
<script>
<interpreter>shell</interpreter>
<filename>load_profile.sh</filename>
<% mac = network_cards.first >
<source><![CDATA[#!/bin/bash
wget -O /tmp/profile/modified.xml http://myserver/<%= network_cards.first[:mac] %>.xml
]]></source>
</script>
</pre-scripts>
</scripts>8.2 Accessing ERB helpers from Ruby scripts #
It is possible to use the ERB helpers in Ruby scripts. To use those helpers,
you need to require the yast and
autoinstall/y2erb libraries and use the
Y2Autoinstall::Y2ERB::TemplateEnvironment class to access
them.
<scripts>
<pre-scripts config:type="list">
<script>
<interpreter>/usr/bin/ruby</interpreter>
<filename>load_profile.rb</filename>
<source><![CDATA[#!/usr/bin/env ruby
require "yast"
require "autoinstall/y2erb"
helpers = Y2Autoinstallation::Y2ERB::TemplateEnvironment.new
# Now you can use the TemplateEnvironment instance to call the helpers
disk_devices = helpers.disks.map { |d| d[:device] }
File.write("/root/disks.txt", disk_devices.join("\n"))
]]></source>
</script>
</pre-scripts>
</scripts>