From eca18e072a482f0ba04e6679c0b3935a3a8d357c Mon Sep 17 00:00:00 2001
From: CyberLeo <cyberleo@cyberleo.net>
Date: Sat, 22 Nov 2014 04:54:57 -0600
Subject: [PATCH] Split check into web and worker bits to reduce check latency

---
 Procfile       |  1 +
 app.rb         |  2 +-
 lib/check.rb   |  4 +--
 lib/checks.rb  | 87 +++++++++++++++++++++++++++++++++++++-------------
 run/.gitignore |  2 ++
 worker.rb      | 15 +++++++++
 6 files changed, 86 insertions(+), 25 deletions(-)
 create mode 100644 run/.gitignore
 create mode 100644 worker.rb

diff --git a/Procfile b/Procfile
index dc85175..4c4e25f 100644
--- a/Procfile
+++ b/Procfile
@@ -1 +1,2 @@
 web:	bundle exec unicorn -p $PORT -c unicorn.rb
+worker:	bundle exec ruby worker.rb
diff --git a/app.rb b/app.rb
index 3a78ebf..9e73be5 100644
--- a/app.rb
+++ b/app.rb
@@ -1,7 +1,7 @@
 require 'sinatra/base'
 require 'checks'
 
-$checks = Checks.new
+$checks = Checks::Web.new
 
 class App < Sinatra::Base
   configure do
diff --git a/lib/check.rb b/lib/check.rb
index 4d4be78..3af27d9 100644
--- a/lib/check.rb
+++ b/lib/check.rb
@@ -22,7 +22,7 @@ class Check
     self.name = params[:name]
     self.uri = params[:uri]
     self.timeout = params[:timeout] || 5
-    self.max_age = params[:max_age] || 30
+    self.max_age = params[:max_age] || 75
   end
 
   def type
@@ -42,7 +42,7 @@ class Check
         @passed = true
       end
     rescue Exception => err
-      STDERR.puts "#{err.class}: #{err.message}\n#{err.backtrace.join("\n")}"
+      STDERR.puts "In #{type}(#{name}): #{err.class}: #{err.message}\n#{err.backtrace.join("\n")}"
       @error = "#{err.class}: #{err.message}"
       @passed = false
     end
diff --git a/lib/checks.rb b/lib/checks.rb
index 3669665..623ca77 100644
--- a/lib/checks.rb
+++ b/lib/checks.rb
@@ -5,35 +5,78 @@ require 'website_check'
 
 
 class Checks
-  @@config = "checks.yml"
-
-  def self.config
-    Configuration.load(@@config)
+  def self.store_path
+    @store_path ||= File.expand_path(File.join(File.dirname(__FILE__), "..", "run", "check.dat"))
   end
 
-  def initialize
-    @checks = []
-  end
+  class Worker
+    @@config = "checks.yml"
 
-  def reload_config
-    return unless !@config || @config.stale?
-    @config ||= self.class.config
-    @checks = @config.map do |check|
-      Kernel.const_get(check[:class]).new(check)
+    def self.config
+      Configuration.load(@@config)
     end
-  end
 
-  def check
-    reload_config
-    threads = @checks.map {|check| Thread.new { check.do_it } }
-    threads.each(&:join)
-  end
+    def initialize
+      @checks = []
+    end
+
+    def reload_config
+      return unless !@config || @config.stale?
+      @config ||= self.class.config
+      @checks = @config.map do |check|
+        Kernel.const_get(check[:class]).new(check)
+      end
+    end
+
+    def check
+      reload_config
+      threads = @checks.map {|check| Thread.new { check.do_it } }
+      threads.each(&:join)
+      store
+    end
+
+    def passed?
+      @checks.map(&:passed?).uniq == [ true ]
+    end
 
-  def passed?
-    @checks.map(&:passed?).uniq == [ true ]
+    def results
+      @checks
+    end
+
+    def store
+      File.open(Checks.store_path, File::RDWR|File::CREAT, 0644) do |fp|
+        fp.flock(File::LOCK_EX)
+        fp.seek(0)
+        fp.truncate(0)
+        fp.write(Marshal.dump(@checks))
+        fp.flush
+        fp.flock(File::LOCK_UN)
+      end
+    end
   end
 
-  def results
-    @checks
+  class Web
+    def load
+      File.open(Checks.store_path, File::RDONLY|File::CREAT, 0644) do |fp|
+        fp.flock(File::LOCK_SH)
+        fp.seek(0)
+        @checks = Marshal.load(fp.read)
+        fp.flock(File::LOCK_UN)
+      end
+    rescue Exception => err
+      @checks = []
+    end
+
+    def check
+      load
+    end
+
+    def passed?
+      @checks.count > 0 && @checks.map(&:passed?).uniq == [ true ] && @checks.map(&:stale?).uniq == [ false ]
+    end
+
+    def results
+      @checks
+    end
   end
 end
diff --git a/run/.gitignore b/run/.gitignore
new file mode 100644
index 0000000..d6b7ef3
--- /dev/null
+++ b/run/.gitignore
@@ -0,0 +1,2 @@
+*
+!.gitignore
diff --git a/worker.rb b/worker.rb
new file mode 100644
index 0000000..d29d9e7
--- /dev/null
+++ b/worker.rb
@@ -0,0 +1,15 @@
+$:.push('lib')
+require 'checks'
+
+$checks = Checks::Worker.new
+
+pid = nil
+while true
+  $checks.reload_config
+  Process.kill("TERM", pid) rescue nil if pid
+  pid = Process.fork do
+    $checks.check
+  end
+  Process.detach(pid)
+  sleep(60)
+end
-- 
2.45.0