snmp wrapper

#!/usr/bin/env ruby
require 'date'
require 'resolv'
require 'uri'
require 'net/telnet'

### external gems
require 'snmp'

class KUtil
    def self.vblist_to_hash (varbind_list)
        r = {}
        varbind_list.each { |x| r[x.name.to_s] = x.value }
        return r
    end

    def self.snmpget (callee, oid)
        x = self.snmpgetbulk(callee, [ oid ] )
        return x[oid] if ! x.nil?
        return nil
    end
    def self.snmpgetbulk (callee, oids)
        if ( callee.kind_of? SNMP::Manager ) then
            begin
                return self.vblist_to_hash(callee.get(oids).varbind_list)
            rescue SNMP::RequestTimeout => e
            end
            return nil
        end

        if ( callee.kind_of? String ) then
            result = nil
            SNMP::Manager.open(:host => callee, :mib_modules => [], :timeout => 3, :retries => 0, :read_community => 'public') { |m|
                result = self.snmpgetbulk(m, oids)
            }
            return result
        end

        puts "#{self.name}.#{__method__} TypeError #{callee.inspect}"
        raise TypeError
    end

    def self.snmpset (callee, oid, value)
        x = self.snmpsetbulk(callee, { oid => value } )
        return x[oid] if ! x.nil?
        return nil
    end
    def self.snmpsetbulk (callee, hashed_oid_value_pairs)
        if ( callee.kind_of? SNMP::Manager ) then
            vblist = hashed_oid_value_pairs.keys.map { |k|
                value = hashed_oid_value_pairs[k]
                if ( value.kind_of? String ) then
                    value = SNMP::OctetString.new(value)
                end
                if ( value.kind_of? Fixnum ) then
                    value = SNMP::Integer.new(value)
                end
                SNMP::VarBind.new(k, value)
            }
            begin
                return self.vblist_to_hash(callee.set(vblist).varbind_list)
            rescue SNMP::RequestTimeout => e
            end
            return nil
        end

        if ( callee.kind_of? String ) then
            result = nil
            SNMP::Manager.open(:host => callee, :mib_modules => [], :timeout => 3, :retries => 0, :write_community => 'private') { |m|
                result = self.snmpsetbulk(m, hashed_oid_value_pairs)
            }
            return result
        end

        puts "#{self.name}.#{__method__} TypeError #{callee.inspect}"
        raise TypeError
    end
end