Add three different check types, exit with non-OK Nagios return codes…

… under various failure conditions.

passenger-check.rb

@@ -3,54 +3,166 @@
 require 'stringio'
 require 'ostruct'
 require 'pp'
+require 'optparse'
 
 module Passenger
 	class Instance
 		attr_accessor :dir, :pid, :processes
-		
+
 		def initialize(info)
 			lines = info.split("\n")
 			@dir = lines.shift
-			@processes = lines.map { |l| 
-				l =~ /^\s+PID: (\d+)\s+Sessions: (\d+)$/
-				OpenStruct.new(:pid => $1, :sessions => $2)
-			}
+			@processes = []
+			for l in lines do
+				l =~ /PID: (\d+)\s+Sessions: (\d+)/
+				if $1 != nil and $2 != nil then
+					@processes << { :pid => $1.to_i, :sessions => $2.to_i }
+				end
+			end
 		end
 	end
-	
+
 	class Status
 		attr_accessor :io, :max, :count, :active, :inactive, :instances
-		
+
 		def initialize(io)
 			@instances = []
 			@io = io
-			
+
 			io.readline
 			@max,@count,@active,@inactive = read_attribute,read_attribute,read_attribute,read_attribute
 			@global_queue = read_attribute(':') == 'no' ? false : true
 			@global_waiting = read_attribute(':')
-			
+
 			io.readline
 			io.readline
-			
+
 			while(! io.eof?)
 				@instances << Instance.new(io.readline("\n\n"))
 			end
 		end
-		
+
 		def percent_used
 		  @count.to_i / @max.to_i
 		end
-		
+
 		private 
-		
+
 		def read_attribute(delim = /\s+=\s+/)
 			io.readline.chomp.split(delim).last
 		end
 	end
 end
 
+def nag_exit(code, msg)
+	txtcodes = [ "OK", "WARNING", "CRITICAL", "UNKNOWN", "DEPEDENT" ]
+	puts "PASSENGER #{txtcodes[code]} - #{msg}"
+	exit(code)
+end
+
+def is_a_number?(s)
+	s.to_s.match(/\A[+-]?\d+?(\.\d+)?\Z/) == nil ? false : true 
+end
+
+def check_max_proc(status, options)
+	pct = status.active.to_f / status.max.to_f
+	code = 0
+	if pct > options[:crit] then
+		code = 2
+	elsif pct > options[:warn] then
+		code = 1
+	end
+	nag_exit(code, "Using #{status.active} of #{status.max} (#{pct}%)")
+end
+
+def check_spike(status, options)
+	for i in status.instances do
+		tot_ses = 0
+		for p in i.processes do
+			tot_ses += p[:sessions]
+		end
+		avg = tot_ses/(i.processes.count)
+		for p in i.processes do
+			if p[:sessions] > (avg * options[:crit]) then
+				nag_exit(2, "PID #{p[:pid]} has #{p[:sessions]} sessions (avg is #{avg})")
+			elsif p[:sessions] > (avg * options[:warn]) then
+				nag_exit(1, "PID #{p[:pid]} has #{p[:sessions]} sessions (avg is #{avg})")
+			end
+		end
+	end
+	nag_exit(0, "No session spikes (avg sessions is #{avg})")
+end
+
+def check_sessions(status, options)
+	for i in status.instances do
+		for p in i.processes do
+			if p[:sessions] > options[:crit] then
+				nag_exit(2, "PID #{p[:pid]} has #{p[:sessions]} sessions")
+			elsif p[:sessions] > options[:warn] then
+				nag_exit(1, "PID #{p[:pid]} has #{p[:sessions]} sessions")
+			end
+		end
+	end
+	nag_exit(0, "No PID has excessive sessions")
+end
+
+options = {}
+OptionParser.new do |opts|
+	opts.banner = %{Usage #{__FILE__} [options]
+
+The values for warning and critical are treated differently depending on the
+check used.
+
+For maxproc:   Warning and critical are percentages; the maximum percent of
+               active processes compared to the total max processes.
+For spike:     Warning and critical are percentages; the maximum percentage
+               per-PID session spike allowed (as compared to the average)
+For sessions:  Warning and critical are integers; the maximum number of
+               sessions per PID
+
+}
+
+	opts.on("-?", "-h", "Help") do |o|
+		nag_exit(3, "Use --help for usage")
+	end
+
+	opts.on("-C", "--check CHECK", "Which check to execute: maxproc/spike/sessions") do |o|
+		if ["maxproc", "spike", "sessions"].include?(o) then
+			options[:check] = o
+		else
+			nag_exit(3, "Unrecognized check name: use --help for usage")
+		end
+	end
+
+	opts.on("-w", "--warn", "--warning WARN", "Level for warning") do |o|
+		if is_a_number?(o) then
+			options[:warn] = o.to_f
+		else
+			nag_exit(3, "Warning threshold #{o} is not numeric")
+		end
+	end
+
+	opts.on("-c", "--crit", "--critical CRIT", "Level for critical") do |o|
+		if is_a_number?(o) then
+			options[:crit] = o.to_f
+		else
+			nag_exit(3, "Critical threshold #{o} is not numeric")
+		end
+	end
+end.parse!(ARGV)
+
+if (options[:check] == nil) or (options[:warn] == nil) or (options[:crit] == nil) then
+	nag_exit(3, "Options check, warn, and crit must all be specified")
+end
+
 Dir['/tmp/passenger_status.*.fifo'].map { |f| open(f) }.each do |io|
 	status = Passenger::Status.new(io)
-	puts "Using #{status.count} of #{status.max} (#{status.percent_used}%)"
-end
+	case options[:check]
+		when "maxproc"
+			check_max_proc(status, options)
+		when "spike"
+			check_spike(status, options)
+		when "sessions"
+			check_sessions(status, options)
+	end
+end