From 86eb7ef1bb928016e851a3920b90a0fd6f9df080 Mon Sep 17 00:00:00 2001
From: Kevin Clark <kev@sisyphus.desk.hq.powerset.com>
Date: Mon, 27 Aug 2007 11:29:40 -0700
Subject: [PATCH] Add notify_when_flapping behavior, doc enhancements

---
 History.txt                               |  1 +
 lib/god.rb                                |  1 +
 lib/god/behaviors/notify_when_flapping.rb | 53 +++++++++++++++++++++++++++++++
 site/index.html                           |  2 +-
 test/configs/real.rb                      |  2 +-
 test/configs/test.rb                      | 16 ++++++++--
 6 files changed, 71 insertions(+), 4 deletions(-)
 create mode 100644 lib/god/behaviors/notify_when_flapping.rb

diff --git a/History.txt b/History.txt
index f5347fc..5a63f8e 100644
--- a/History.txt
+++ b/History.txt
@@ -8,6 +8,7 @@
 * Bug Fixes
   * Use exit!(0) instead of exit! in god binary to exit with code 0 (instead of default -1)
   * Command line group control fixed
+  * Add :notify_when_flapping behavior to check for oscillation
 
 == 0.3.0 / 2007-08-17
 
diff --git a/lib/god.rb b/lib/god.rb
index c0d3e41..acc04e7 100644
--- a/lib/god.rb
+++ b/lib/god.rb
@@ -9,6 +9,7 @@ require 'god/system/process'
 
 require 'god/behavior'
 require 'god/behaviors/clean_pid_file'
+require 'god/behaviors/notify_when_flapping'
 
 require 'god/condition'
 require 'god/conditions/timeline'
diff --git a/lib/god/behaviors/notify_when_flapping.rb b/lib/god/behaviors/notify_when_flapping.rb
new file mode 100644
index 0000000..0b6a270
--- /dev/null
+++ b/lib/god/behaviors/notify_when_flapping.rb
@@ -0,0 +1,53 @@
+module God
+  module Behaviors
+    
+    class NotifyWhenFlapping < Behavior
+      attr_accessor :failures # number of failures 
+      attr_accessor :seconds  # number of seconds
+      attr_accessor :notifier # class to notify with
+      
+      def initialize
+        super
+        @startup_times = []
+      end
+      
+      def valid?
+        valid = true
+        valid &= complain("You must specify the 'failures' attribute for :notify_when_flapping") unless self.failures
+        valid &= complain("You must specify the 'seconds' attribute for :notify_when_flapping") unless self.seconds
+        valid &= complain("You must specify the 'notifier' attribute for :notify_when_flapping") unless self.notifier
+        
+        valid &= complain("The 'notifier' attribute must be a class") unless self.notifier.is_a? Class
+        
+        # Must take one arg or variable args
+        unless self.notifier.respond_to?(:notify) and [1,-1].include?(self.notifier.method(:notify).arity)
+          valid &= complain("The 'notifier' class must have a method 'notify' which takes 1 or variable args")
+        end
+        
+        valid
+      end
+  
+      def before_start
+        now = Time.now.to_i
+        @startup_times << now
+        check_for_flapping(now)
+      end
+      
+      def before_restart
+        now = Time.now.to_i
+        @startup_times << now
+        check_for_flapping(now)
+      end
+      
+      private
+        
+        def check_for_flapping(now)
+          @startup_times = @startup_times.select {|time| time >= now - self.seconds }
+          if @startup_times.length >= self.failures
+            self.notifier.notify("#{self.watch.name} has called start/restart #{@startup_times.length} times in #{self.seconds} seconds")
+          end
+        end
+    end
+  
+  end
+end
\ No newline at end of file
diff --git a/site/index.html b/site/index.html
index aab461b..c63b4b2 100644
--- a/site/index.html
+++ b/site/index.html
@@ -230,7 +230,7 @@ code {
 	
 	<h1>Requirements</h1>
 	
-	<p>God currently only works on <b>Linux (kernel 2.6.15+), BSD,</b> and <b>Darwin</b> systems. No support for Windows is planned.</p>
+	<p>God currently only works on <b>Linux (kernel 2.6.15+), BSD,</b> and <b>Darwin</b> systems. No support for Windows is planned. Event based conditions on Linux systems require the <code>cn</code> (connector) kernel module loaded or compiled in to the kernel and god must be run as root.</p>
 	
 	<p>The following systems have been tested. Help us test it on others!</p>
 	
diff --git a/test/configs/real.rb b/test/configs/real.rb
index 344f9bb..1beaad7 100644
--- a/test/configs/real.rb
+++ b/test/configs/real.rb
@@ -17,7 +17,7 @@ God.watch do |w|
   w.behavior(:clean_pid_file) do |b|
     b.pid_file = pid_file
   end
-
+  
   # start if process is not running
   w.start_if do |start|
     start.condition(:process_running) do |c|
diff --git a/test/configs/test.rb b/test/configs/test.rb
index 265c4bd..81c2394 100644
--- a/test/configs/test.rb
+++ b/test/configs/test.rb
@@ -12,6 +12,12 @@ God.init do |g|
   # g.pid_file_directory = 
 end
 
+class SimpleNotifier
+  def self.notify(str)
+    puts "Notifying: #{str}"
+  end
+end
+
 God.watch do |w|
   w.name = "local-3000"
   w.interval = 5.seconds
@@ -21,14 +27,20 @@ God.watch do |w|
   w.restart_grace = 5.seconds
   w.stop_grace = 5.seconds
   w.autostart = true
-  w.uid = 'tom'
-  w.gid = 'tom'
+  w.uid = 'kev'
+  w.gid = 'kev'
   w.group = 'mongrels'
   w.pid_file = File.join(RAILS_ROOT, "log/mongrel.pid")
   
   # clean pid files before start if necessary
   w.behavior(:clean_pid_file)
   
+  w.behavior(:notify_when_flapping) do |b|
+    b.failures = 5
+    b.seconds = 60.seconds
+    b.notifier = SimpleNotifier
+  end
+  
   # determine the state on startup
   w.transition(:init, { true => :up, false => :start }) do |on|
     on.condition(:process_running) do |c|
-- 
2.11.4.GIT