# -*- ruby -*-

# vim: set noet nosta sw=4 ts=4 :

#encoding: utf-8

require 'arborist/monitor' unless defined?( Arborist::Monitor )

require 'netsnmp'

# SNMP checks for Arborist.  Requires an SNMP agent to be installed

# on target machine, and the various "pieces" enabled for your platform.

#

# For example, for disk monitoring with Net-SNMP, you'll want to set

# 'includeAllDisks' in the snmpd.conf. bsnmpd on FreeBSD benefits from

# the 'bsnmp-ucd' package.  Etc.

#

module Arborist::Monitor::SNMP

	using Arborist::TimeRefinements

	extend Configurability, Loggability

	# Loggability API

	log_to :arborist_snmp

	# Always request the node addresses and any config.

	USED_PROPERTIES = [ :addresses, :config ].freeze

	# The OID that returns the system environment.

	IDENTIFICATION_OID = '1.3.6.1.2.1.1.1.0'

	# Global defaults for instances of this monitor

	#

	configurability( 'arborist.snmp' ) do

		setting :timeout, default: 2

		setting :retries, default: 1

		setting :community, default: 'public'

		setting :version, default: '2c'

		setting :port, default: 161

		# How many hosts to check simultaneously

		setting :batchsize, default: 25

	end

	# The mapping of addresses back to node identifiers.

	attr_reader :identifiers

	# The results hash that is sent back to the manager.

	attr_reader :results

	### Connect to the SNMP daemon and yield.

	###

	def run( nodes )

		# Create mapping of addresses back to node identifiers,

		# and retain any custom (overrides) config per node.

		#

		@identifiers = {}

		@results     = {}

		nodes.each_pair do |(identifier, props)|

			next unless props.key?( 'addresses' )

			address = props[ 'addresses' ].first

			self.identifiers[ address ] = [ identifier, props['config'] ]

		end

		# Perform the work!

		#

		mainstart  = Time.now

		threads    = ThreadGroup.new

		batchcount = nodes.size / Arborist::Monitor::SNMP.batchsize

		self.log.debug "Starting SNMP run for %d nodes" % [ nodes.size ]

		self.identifiers.keys.each_slice( Arborist::Monitor::SNMP.batchsize ).each_with_index do |slice, batch|

			slicestart = Time.now

			self.log.debug "  %d hosts (batch %d of %d)" % [

				slice.size,

				batch + 1,

				batchcount + 1

			]

			slice.each do |host|

				thr = Thread.new do

					config = self.identifiers[ host ].last || {}

					opts = {

						host:      host,

						port:      config[ 'port' ]      || Arborist::Monitor::SNMP.port,

						version:   config[ 'version' ]   || Arborist::Monitor::SNMP.version,

						community: config[ 'community' ] || Arborist::Monitor::SNMP.community,

						timeout:   config[ 'timeout' ]   || Arborist::Monitor::SNMP.timeout,

						retries:   config[ 'retries' ]   || Arborist::Monitor::SNMP.retries

					}

					begin

						NETSNMP::Client.new( opts ) do |snmp|

							Thread.current[ :system ] = snmp.get( oid: IDENTIFICATION_OID )

							yield( host, snmp )

						end

					rescue => err

						self.log.error "%s: %s\n%s" % [ host, err.message, err.backtrace.join("\n  ") ]

						self.results[ host ] = {

							error: "Exception (%s: %s)" % [ err.class.name, err.message ]

						}

					end

				end

				threads.add( thr )

			end

			# Wait for thread completions

			threads.list.map( &:join )

			self.log.debug "  finished after %0.1f seconds." % [ Time.now - slicestart ]

		end

		self.log.debug "Completed SNMP run for %d nodes after %0.1f seconds." % [ nodes.size, Time.now - mainstart ]

		# Map everything back to identifier -> attribute(s), and send to the manager.

		#

		reply = self.results.each_with_object({}) do |(address, results), hash|

			identifier = self.identifiers[ address ] or next

			hash[ identifier.first ] = results

		end

		return reply

	ensure

		@identifiers = {}

		@results     = {}

	end

	### Return the current SNMP connection system string.

	def system

		return Thread.current[ :system ]

	end

end # Arborist::Monitor::SNMP

require 'arborist/monitor/snmp/cpu'

require 'arborist/monitor/snmp/disk'

require 'arborist/monitor/snmp/process'

require 'arborist/monitor/snmp/memory'