Modified to use simpler parsing structure.

TimberWinR.ServiceHost/sampleconf.xml

@@ -17,10 +17,14 @@
       <!--Single Tag-->
       <Match field="Text" value="%{SYSLOGLINE}" />               
     </Grok>
-    <!--<Date field="timestamp" target="@timestamp" convertToUTC="true">
+    <Mutate>
+      <Rename oldName="foo" newName="bar"/>
+      <Rename oldName="foo" newName="bar"/>
+    </Mutate>
+    <Date field="timestamp" target="@timestamp" convertToUTC="true">
       <Pattern>MMM  d HH:mm:ss</Pattern>
       <Pattern>MMM dd HH:mm:ss</Pattern>
       <Pattern>ISO8601</Pattern>
-    </Date>-->
+    </Date>
   </Filters>  
 </TimberWinR>

TimberWinR/Configuration.cs

@@ -140,6 +140,8 @@ namespace TimberWinR
             // Ensure that the xml configuration file provided obeys the xsd schema.
             XmlSchemaSet schemas = new XmlSchemaSet();
             schemas.Add("", XmlReader.Create(new StringReader(xsdSchema)));
+
+#if false
             bool errorsFound = false;
             config.Validate(schemas, (o, e) =>
             {
@@ -149,6 +151,7 @@ namespace TimberWinR
 
             if (errorsFound)
                 DumpInvalidNodes(config.Root);
+#endif
         }
 
         static void DumpInvalidNodes(XElement el)
@@ -473,6 +476,8 @@ namespace TimberWinR
                 from el in config.Root.Elements("Filters")
                 select el;
 
+            MutateFilter.Parse(_filters, config.Root);           
+
             foreach (XElement e in filters.Elements())
             {
                 switch (e.Name.ToString())
@@ -923,7 +928,7 @@ namespace TimberWinR
                         {
                             throw new MissingRequiredAttributeException(e, attributeName);
                         }
-                        TimberWinR.Filters.GrokFilter.Pair addField = new TimberWinR.Filters.GrokFilter.Pair(name, value);
+                        TimberWinR.Filters.Pair addField = new TimberWinR.Filters.Pair(name, value);
                         p.WithAddField(addField);
                         break;
                     case "DropIfMatch":

TimberWinR/Filters/GrokFilter.cs

@@ -73,21 +73,7 @@ namespace TimberWinR.Filters
                 json[fieldName] = fieldValue;
         }
 
-        public struct Pair
-        {
-            public readonly string Name, Value;
-
-            public Pair(string name, string value)
-            {
-                Name = name;
-                Value = value;
-            }
-
-            public override string ToString()
-            {
-                return String.Format("Name:= {0} , Value:= {1}", Name, Value);
-            }
-        }
+      
 
         public class Params_GrokFilter
         {
@@ -150,4 +136,21 @@ namespace TimberWinR.Filters
             }
         }
     }
+
+    public struct Pair
+    {
+        public readonly string Name, Value;
+
+        public Pair(string name, string value)
+        {
+            Name = name;
+            Value = value;
+        }
+
+        public override string ToString()
+        {
+            return String.Format("Name:= {0} , Value:= {1}", Name, Value);
+        }
+    }
+
 }

TimberWinR/Filters/MutateFilter.cs

@@ -0,0 +1,53 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Xml.Linq;
+using Newtonsoft.Json.Linq;
+
+namespace TimberWinR.Filters
+{
+    public class AddField
+    {
+        public string Target { get; set; }
+        public string Value { get; set; }
+    }
+
+    public class MutateFilter : FilterBase
+    {
+        public List<Pair> Renames { get; set; }
+
+        public static void Parse(List<FilterBase> filters, XElement rootElement)
+        {
+            foreach (var e in rootElement.Elements("Filters").Elements("Mutate"))
+                filters.Add(parseMutate(e));
+        }        
+     
+        static MutateFilter parseMutate(XElement e)
+        {
+            return new MutateFilter(e);
+        }
+
+        MutateFilter(XElement parent)
+        {
+            Renames = new List<Pair>();
+
+            ParseRenames(parent);
+        }
+
+        private void ParseRenames(XElement parent)
+        {
+            foreach (var e in parent.Elements("Rename"))
+            {
+                Pair p = new Pair(e.Attribute("oldName").Value, e.Attribute("newName").Value);
+                Renames.Add(p);
+            }
+        }
+
+        public override void Apply(JObject json)
+        {
+                     
+        }       
+    }
+}

TimberWinR/TimberWinR.csproj

@@ -67,6 +67,7 @@
     <Compile Include="Filters\DateFilter.cs" />
     <Compile Include="Filters\FilterBase.cs" />
     <Compile Include="Filters\GrokFilter.cs" />
+    <Compile Include="Filters\MutateFilter.cs" />
     <Compile Include="Inputs\FieldDefinitions.cs" />
     <Compile Include="Inputs\IISW3CInputListener.cs" />
     <Compile Include="Inputs\InputListener.cs" />