Patlite control ruby library

patlite.rb

# Usage;
#
# Patlite.host = "192.168.254.209"
# red = Patlite.new(:red)
# p red.state?
# #=> :off / :on
# if red.off?
#   red.on
# end

require "snmp" # NOTE: ref: http://snmplib.rubyforge.org/doc/index.html
class Patlite
  attr_accessor :target

  @@host = "127.0.0.1"
  @@secret = "private"
  @@status = {}

  # NOTE: ref: http://www.patlite.jp/download/NH-SPL-Manual8158-A.pdf
  CONTROL_PREFIX  = "1.3.6.1.4.1.20440.4.1.5.1.2.1.2"
  OFFTIMER_PREFIX = "1.3.6.1.4.1.20440.4.1.5.1.2.1.3"
  MONITOR_PREFIX  = "1.3.6.1.4.1.20440.4.1.5.1.2.1.4"
  TARGET_SUFFIX = {red: "1", yellow: "2", green: "3"}

  ON = 2
  OFF = 1

  def initialize(target)
    raise NameError, "#{target} not found in #{TARGET_SUFFIX.keys}" if ! TARGET_SUFFIX.keys.include?(target)
    @target = target
    # NOTE: OID Pre-create for memoize
    @control_oids = {}
    @offtimer_oids = {}
    @monitor_oids = {}
    TARGET_SUFFIX.each do |k, v|
      @control_oids[k]  = SNMP::ObjectId.new("#{CONTROL_PREFIX}.#{v}")
      @offtimer_oids[k] = SNMP::ObjectId.new("#{OFFTIMER_PREFIX}.#{v}")
      @monitor_oids[k]  = SNMP::ObjectId.new("#{MONITOR_PREFIX}.#{v}")
    end
  end

  def on  ; set ON  ; state? ; end
  def off ; set OFF ; state? ; end

  def on?  ; state?(false) == ON  ; end
  def off? ; state?(false) == OFF ; end

  def state?(friendly = true)
    update_status
    if friendly
      case true
      when @@status[@target] == ON
        :on
      when @@status[@target] == OFF
        :off
      else
        @@status[@target]
      end
    else
      @@status[@target]
    end
  end

  # NOTE: for accessor to class variables
  class << self
    def host ; @@host ; end
    def host=(value) ; @@host = value ; end
    def secret ; @@secret ; end
    def secret=(value) ; @@secret = value ; end
  end
  def host ; @@host ; end
  def secret ; @@secret ; end

  private
  def update_status
    # TODO: @@status cache(memoize) for performance and reduce communication
    SNMP::Manager.open(Host: @@host, Community: @@secret) do |manager|
      r = manager.get(@monitor_oids.values)
      r.varbind_list.each do |i|
        target = @monitor_oids.find{|k, v| v == i.name}.first
        @@status[target] = i.value.to_i
      end
    end
  end

  def set(value, offtimer = 0) # NOTE: OffTimer is count down timer to OFF (unit is sec, 0=disable)
    SNMP::Manager.open(Host: @@host, Community: @@secret) do |manager|
      manager.set([
        SNMP::VarBind.new(@control_oids[@target], SNMP::Integer.new(value)),
        SNMP::VarBind.new(@offtimer_oids[@target], SNMP::Integer.new(offtimer)),
      ])
    end
  end
end