lvm_support.rb

# lvm_support: true/nil
#   Whether there is LVM support (based on the presence of the "vgs" command)
Facter.add('lvm_support') do
  confine do
    Facter.value('kernel') == 'Linux'
  end

  setcode do
    vgdisplay = Facter::Util::Resolution.which('vgs')
    vgdisplay.nil? ? nil : true
  end
end

# lvm_vgs: [0-9]+
#   Number of VGs
vg_list = []
Facter.add('lvm_vgs') do
  confine lvm_support: true

  if Facter.value(:lvm_support)
    vgs = Facter::Core::Execution.execute('vgs -o name --noheadings 2>/dev/null', timeout: 30)
  end

  if vgs.nil?
    setcode { 0 }
  else
    vg_list = vgs.split
    setcode { vg_list.length }
  end
end

# lvm_vg_[0-9]+
#   VG name by index
vg_list.each_with_index do |vg, i|
  Facter.add("lvm_vg_#{i}") { setcode { vg } }
  Facter.add("lvm_vg_#{vg}_pvs") do
    setcode do
      pvs = Facter::Core::Execution.execute("vgs -o pv_name #{vg} 2>/dev/null", timeout: 30)
      res = nil
      unless pvs.nil?
        res = pvs.split("\n").select { |l| l =~ %r{^\s+/} }.map(&:strip).sort.join(',')
      end
      res
    end
  end
end

# lvm_pvs: [0-9]+
#   Number of PVs
pv_list = []
Facter.add('lvm_pvs') do
  confine lvm_support: true
  if Facter.value(:lvm_support)
    pvs = Facter::Core::Execution.execute('pvs -o name --noheadings 2>/dev/null', timeout: 30)
  end

  if pvs.nil?
    setcode { 0 }
  else
    pv_list = pvs.split
    setcode { pv_list.length }
  end
end

# lvm_pv_[0-9]+
#   PV name by index
pv_list.each_with_index do |pv, i|
  Facter.add("lvm_pv_#{i}") { setcode { pv } }
end