Facter custom fact to query installed RPMs

rpms.rb

Facter.add(:rpms) do
  setcode do
    gs = "\x1D"
    rs = "\x1E"
    us = "\x1F"
    # see:
    #  "rpm --querytags"
    #  http://rpm5.org/docs/api/queryformat.html
    #  http://www.rpm.org/max-rpm/ch-queryformat-tags.html
    rpmtags = {
      'name' => "%{NAME}",
      'version' => "%{VERSION}",
      'release' => "%{RELEASE}",
      'epoch' => "%{EPOCH}",
      'summary' => "%{SUMMARY}",
      'description' => "%{DESCRIPTION}",
      'buildtime' => "%{BUILDTIME}",
      'buildhost' => "%{BUILDHOST}",
      'installtime' => "%{INSTALLTIME}",
      'size' => "%{SIZE}",
      'distribution' => "%{DISTRIBUTION}",
      'vendor' => "%{VENDOR}",
      'license' => "%{LICENSE}",
      'packager' => "%{PACKAGER}",
      'group' => "%{GROUP}",
      'arch' => "%{ARCH}",
      'requires' => "[%{REQUIRENAME} %{REQUIREFLAGS:depflags} %{REQUIREVERSION}#{us}]",
      'providees' => "[%{PROVIDENAME} %{PROVIDEFLAGS:depflags} %{PROVIDEVERSION}#{us}]",
      'conflicts' => "[%{CONFLICTNAME} %{CONFLICTFLAGS:depflags} %{CONFLICTVERSION}#{us}]",
      'obseletes' => "[%{OBSOLETENAME} %{OBSOLETEFLAGS:depflags} %{OBSOLETEVERSION}#{us}]",
      'sigmd5' => "%{SIGMD5}",
      'sha1header' => "%{SHA1HEADER}",
    }
    rpmquery = "rpm -qa --qf '#{rpmtags.values.join(rs)}#{gs}'"
    Hash[
      Facter::Core::Execution.exec(rpmquery).split(gs).map do |s|
        h = Hash[rpmtags.keys.zip(s.split(rs).map{ |v| v.include?(us) ? v.split(us).map{ |v| v.strip } : v.strip })]
        [h.delete('name'), h]
      end
    ]
  end
end