usable_cores on SmartOS

# Sets the cpu_cap fact to the cpu_cap setting for the zone.
# We use kstat to retrive the value because it is not availble via mdata-get
# If no cap can be found it will be set to 0
Facter.add('cpu_cap') do
  confine :operatingsystem => "SmartOS"
  setcode do
    cpu_cap_value = 0
    if Facter::Util::Resolution.which('kstat')
      cpu_cap_string = Facter::Util::Resolution.exec('kstat -n /cpucaps/ -c zone_caps -s value -C')
      cpu_cap_value = cpu_cap_string.split(":").last unless cpu_cap_string == nil
    end
    cpu_cap_value
  end
end



# Adds a usable_cores fact which represents the number of cores the VM
# actually has access to.
# For KVM this is effectively the number of VCPU's for Zones it is the CPU_CAP setting
#
Facter.add('usable_cores') do
  setcode do
    cpu_cap = Facter.value('cpu_cap')

    # If cpu_cap is set, set the number of usable cores based off it
    # If it's a fractional part of a core we always round up to at least 1 core
    if cpu_cap != nil && cpu_cap.to_i > 0
      usable_cores = (cpu_cap.to_i / 100).ceil
    else
      # If cpu_cap is not set then we default to all available cores
      # which happens to be correct for KVM (physical cores is the number of VCPUS allocated)
      # and SmartOS zones, if no cap is set the zone has access to all available cores
      usable_cores = Facter.value("processorcount")
    end

    # we always return at least 1 core
    usable_cores || 1
  end
end