rubyrun_rss__.rb in rubyrun-0.9.7

- old
+ new

@@ -39,11 +39,10 @@
     @rss_filename = rss_filename
     @html_filename = html_filename
     @apps_name = Rails::Configuration.new.root_path.split('/').last
     @rss_xml_destination = "#{@directory}/#{@rss_filename}"
     create_channel_content unless File::exists?(@rss_xml_destination)
-    @rss = load_rss_content
   end
 
   # Create the RSS channel
   def create_channel_content
     content = RSS::Maker.make(RUBYRUN_RSS_VERSION) do |m|
@@ -68,19 +67,32 @@
     File.open("#{@directory}/#{filename}", 'w') { |file| file.puts html_content }
     item = RSS::Rss::Channel::Item.new
     item.title = sprintf(title, "#{$rubyrun_startup_id_type} #{$rubyrun_startup_id}",Time.now.strftime("%H:%M:%S"))
     item.description = sprintf(description, @apps_name, "#{$rubyrun_startup_id_type} #{$rubyrun_startup_id}", Time.now.strftime("%H:%M:%S"))
     item.link = "http://#{$rubyrun_host_with_port}/#{RUBYRUN_RSS_FOLDER}/#{filename}"
-    sleep(rand(3))
-    @rss = load_rss_content    
-    remove_old_item(@rss) if @rss.items.length == $rubyrun_report_shift_age
-    @rss.items << item
+    acquire_lock
+    rss = load_rss_content    
+    remove_old_item(rss) if rss.items.length == $rubyrun_report_shift_age
+    rss.items << item
     File.open(@rss_xml_destination,"w") do |f|
-      f.write(@rss)
-    end    
+      f.write(rss)
+    end
+    release_lock
   end
   
   private
+
+  # Acquire a lock so that only one Ruby process can write to the RSS XML file
+  def acquire_lock
+    @lock_file = File.new(File.join(@directory,'lock'),'w')
+    @lock_file.flock(File::LOCK_EX)
+  end
+
+  # Release a lock after writing the RSS XML file content
+  def release_lock
+    @lock_file.flock(File::LOCK_UN)
+    @lock_file.close
+  end
   
   # Load the existing RSS XML file. Create a new channel if the channel is blank
   def load_rss_content
     content = "" # raw content of rss feed will be loaded here
     open(@rss_xml_destination) do |s| content = s.read end
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