Change event '[]' method to check @data (not just @data[@fields]) if the key starts with '@' so that grep filtering can match standard parse values

lib/logstash/event.rb

@@ -70,7 +70,16 @@ class LogStash::Event
 
   # field-related access
   public
-  def [](key); @data["@fields"][key] end # def []
+  def [](key)
+    # If the key isn't in fields and it starts with an "@" sign, get it out of data instead of fields
+    if ! @data["@fields"].has_key?(key) and key.slice(0,1) == "@"
+      @data[key]
+    # Exists in @fields (returns value) or doesn't start with "@" (return null)
+    else
+      @data["@fields"][key]
+    end
+  end # def []
+  
   def []=(key, value); @data["@fields"][key] = value end # def []=
   def fields; return @data["@fields"] end # def fields