Initial version

plugins/other/unicorn_status

@@ -0,0 +1,79 @@
+#!/usr/bin/env ruby
+#
+#	unicorn_status - A munin plugin for Linux to monitor unicorn processes
+#
+#  Copyright (C) 2010 Shinji Furuya - shinji.furuya@gmail.com
+#  Licensed under the MIT license:
+#  http://www.opensource.org/licenses/mit-license.php
+#
+
+# set path to your rails app
+RAILS_ROOT = "/path/to/rails/app"
+
+module Munin
+  class UnicornStatus
+    attr_reader :pid_file
+
+    def initialize(rails_root)
+      @pid_file = "#{rails_root}/tmp/pids/unicorn.pid"
+    end
+
+    def master_pid
+      File.read(pid_file).to_i
+    end
+
+    def worker_pids
+      result = []
+      ps_output = `ps w --ppid #{master_pid}`
+      ps_output.split("\n").each do |line|
+        chunks = line.strip.split(/\s+/, 5)
+        pid, pcmd = chunks[0], chunks[4]
+        next if pid !~ /\A\d+\z/ or pcmd !~ /worker/
+          result << pid.to_i
+      end
+      result
+    end
+
+    def worker_count
+      worker_pids.size
+    end
+
+    def idle_worker_count
+      result = 0
+      before_cpu = {}
+      worker_pids.each do |pid|
+        before_cpu[pid] = cpu_time(pid)
+      end
+      sleep 1
+      after_cpu = {}
+      worker_pids.each do |pid|
+        after_cpu[pid] = cpu_time(pid)
+      end
+      worker_pids.each do |pid|
+        result += 1 if after_cpu[pid] - before_cpu[pid] == 0
+      end
+      result
+    end
+
+    def cpu_time(pid)
+      usr, sys = `cat /proc/#{pid}/stat | awk '{print $14,$15 }'`.strip.split(/\s+/).collect { |i| i.to_i }
+      usr + sys
+    end
+  end
+end
+
+case ARGV[0]
+when "autoconf"
+  puts "yes"
+when "config"
+  puts "graph_title Unicorn - Status"
+  puts "graph_args -l 0"
+  puts "graph_vlabel number of workers"
+  puts "graph_category Unicorn"
+  puts "total_worker.label total_workers"
+  puts "idle_worker.label idle_workers"
+else
+  m = Munin::UnicornStatus.new(RAILS_ROOT)
+  puts "total_worker.value #{m.worker_count}"
+  puts "idle_worker.value #{m.idle_worker_count}"
+end