--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/arborist/monitor/snmp/memory.rb	Wed Sep 07 15:23:42 2016 -0700
@@ -0,0 +1,83 @@
+# -*- ruby -*-
+# vim: set noet nosta sw=4 ts=4 :
+
+require 'arborist/monitor/snmp' unless defined?( Arborist::Monitor::SNMP )
+
+# SNMP memory availability checks.
+# Returns total available memory in Kb to the 'available_memory' attribute.
+#
+class Arborist::Monitor::SNMP::Memory
+	include Arborist::Monitor::SNMP
+
+	extend Loggability
+	log_to :arborist
+
+	# OIDS for discovering memory usage.
+	#
+	MEMORY = {
+		mem_avail: '1.3.6.1.4.1.2021.4.6.0'
+	}
+
+	# Global defaults for instances of this monitor
+	#
+	DEFAULT_OPTIONS = {
+		error_at: 95, # in percent full
+	}
+
+
+	### This monitor is complex enough to require creating an instance from the caller.
+	### Provide a friendlier error message the class was provided to exec() directly.
+	###
+	def self::run( nodes )
+		return new.run( nodes )
+	end
+
+
+	### Create a new instance of this monitor.
+	###
+	def initialize( options=DEFAULT_OPTIONS )
+		options = DEFAULT_OPTIONS.merge( options || {} )
+		options.each do |name, value|
+			self.public_send( "#{name.to_s}=", value )
+		end
+	end
+
+	# Set an error if memory used is below this many kilobytes.
+	attr_accessor :error_at
+
+
+	### Perform the monitoring checks.
+	###
+	def run( nodes )
+		super do |snmp, host|
+			self.gather_free_memory( snmp, host )
+		end
+	end
+
+
+	#########
+	protected
+	#########
+
+	### Collect available memory information for +host+ from an existing
+	### (and open) +snmp+ connection.
+	###
+	def gather_free_memory( snmp, host )
+		self.log.debug "Getting available memory for: %s" % [ host ]
+		mem_avail = snmp.get( SNMP::ObjectId.new( MEMORY[:mem_avail] ) ).varbind_list.first.value.to_f
+		self.log.debug "  Available memory on %s: %0.2f" % [ host, mem_avail ]
+
+		config = @identifiers[ host ].last || {}
+		error_at = config['error_at'] || self.error_at
+		if mem_avail <= error_at
+			@results[ host ] = {
+				error: "Available memory is under %0.1fMB" % [ error_at.to_f / 1024 ],
+				available_memory: mem_avail
+			}
+		else
+			@results[ host ] = { available_memory: mem_avail }
+		end
+	end
+
+end # class Arborist::Monitor::SNMP::Memory
+