From 2513384d3f9b49869954f5e7dfe928f21a3afa89 Mon Sep 17 00:00:00 2001
From: Tom Werner <tom@tom.(none)>
Date: Fri, 26 Oct 2007 18:12:16 -0700
Subject: [PATCH] start work on complex condition

---
 lib/god.rb                            |  1 +
 lib/god/conditions/complex.rb         | 86 +++++++++++++++++++++++++++++++++++
 test/configs/complex/complex.god      | 59 ++++++++++++++++++++++++
 test/configs/complex/simple_server.rb |  3 ++
 4 files changed, 149 insertions(+)
 create mode 100644 lib/god/conditions/complex.rb
 create mode 100644 test/configs/complex/complex.god
 create mode 100755 test/configs/complex/simple_server.rb

diff --git a/lib/god.rb b/lib/god.rb
index 59421ef..dbddbc2 100644
--- a/lib/god.rb
+++ b/lib/god.rb
@@ -33,6 +33,7 @@ require 'god/conditions/degrading_lambda'
 require 'god/conditions/flapping'
 require 'god/conditions/http_response_code'
 require 'god/conditions/disk_usage'
+require 'god/conditions/complex'
 
 require 'god/contact'
 require 'god/contacts/email'
diff --git a/lib/god/conditions/complex.rb b/lib/god/conditions/complex.rb
new file mode 100644
index 0000000..50dd8ed
--- /dev/null
+++ b/lib/god/conditions/complex.rb
@@ -0,0 +1,86 @@
+module God
+  module Conditions
+    
+    class Complex < PollCondition
+      AND = 0x1 
+      OR  = 0x2
+      NOT = 0x4
+        
+      def initialize()
+        super
+        
+        @oper_stack = []
+        @op_stack = []
+        
+        @this = nil
+      end
+      
+      def valid?
+        @oper_stack.inject(true) { |acc, oper| acc & oper.valid? }
+      end
+      
+      def prepare
+        @oper_stack.each { |oper| oper.prepare }
+      end
+      
+      def new_oper(kind, op)
+        oper = Condition.generate(kind, self.watch)
+        @oper_stack.push(oper)
+        @op_stack.push(op)
+        oper
+      end
+      
+      def this(kind)
+        @this = Condition.generate(kind, self.watch)
+        yield @this if block_given?
+      end
+      
+      def and(kind)
+        oper = new_oper(kind, 0x1)
+        yield oper if block_given?
+      end
+      
+      def and_not(kind)
+        oper = new_oper(kind, 0x5)
+        yield oper if block_given?
+      end
+      
+      def or(kind)
+        oper = new_oper(kind, 0x2)
+        yield oper if block_given?
+      end
+      
+      def or_not(kind)
+        oper = new_oper(kind, 0x6)
+        yield oper if block_given?
+      end
+      
+      def test
+        if @this.nil?
+          # Although this() makes sense semantically and therefore
+          # encourages easy-to-read conditions, being able to omit it
+          # allows for more DRY code in some cases, so we deal with a
+          # nil @this here by initially setting res to true or false,
+          # depending on whether the first operator used is AND or OR
+          # respectively.
+          if 0 < @op_stack[0] & AND
+            res = true
+          else
+            res = false
+          end
+        else
+          res = @this.test
+        end
+        
+        @op_stack.each do |op|
+          cond = @oper_stack.shift
+          eval "res " + ((0 < op & AND) ? "&&" : "||") + "= " + ((0 < op & NOT) ? "!" : "") + "cond.test"
+          @oper_stack.push cond
+        end
+        
+        res
+      end
+    end
+    
+  end
+end
\ No newline at end of file
diff --git a/test/configs/complex/complex.god b/test/configs/complex/complex.god
new file mode 100644
index 0000000..d03d635
--- /dev/null
+++ b/test/configs/complex/complex.god
@@ -0,0 +1,59 @@
+God.watch do |w|
+  w.name = "complex"
+  w.interval = 5.seconds
+  w.start = File.join(GOD_ROOT, *%w[test configs complex simple_server.rb])
+  # w.log = File.join(GOD_ROOT, *%w[test configs child_events god.log])
+  
+  # determine the state on startup
+  w.transition(:init, { true => :up, false => :start }) do |on|
+    on.condition(:process_running) do |c|
+      c.running = true
+    end
+  end
+  
+  # determine when process has finished starting
+  w.transition([:start, :restart], :up) do |on|
+    on.condition(:process_running) do |c|
+      c.running = true
+    end
+    
+    # failsafe
+    on.condition(:tries) do |c|
+      c.times = 2
+      c.transition = :start
+    end
+  end
+
+  # start if process is not running
+  w.transition(:up, :start) do |on|
+    on.condition(:process_exits)
+  end
+  
+  # restart if process is misbehaving
+  w.transition(:up, :restart) do |on|
+    on.condition(:complex) do |cc|
+      cc.and(:cpu_usage) do |c|
+        c.above = 0.percent
+        c.times = 1
+      end
+      
+      cc.and(:memory_usage) do |c|
+        c.above = 0.megabytes
+        c.times = 3
+      end
+    end
+  end
+  
+  # lifecycle
+  w.lifecycle do |on|
+    on.condition(:flapping) do |c|
+      c.to_state = [:start, :restart]
+      c.times = 5
+      c.within = 20.seconds
+      c.transition = :unmonitored
+      c.retry_in = 10.seconds
+      c.retry_times = 2
+      c.retry_within = 5.minutes
+    end
+  end
+end
\ No newline at end of file
diff --git a/test/configs/complex/simple_server.rb b/test/configs/complex/simple_server.rb
new file mode 100755
index 0000000..91b7a25
--- /dev/null
+++ b/test/configs/complex/simple_server.rb
@@ -0,0 +1,3 @@
+#! /usr/bin/env ruby
+
+loop { puts 'server'; sleep 1 }
\ No newline at end of file
-- 
2.11.4.GIT