Json layout renderer for nlog + rabbitMQ target + logstash

JsonLayoutRenderer

using System.Globalization;
using System.Text;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using NLog;
using NLog.LayoutRenderers;

namespace Cats.Middleware.Logging
{
    [LayoutRenderer("json")]
    public class JsonLayoutRenderer : LayoutRenderer
    {
        protected override void Append(StringBuilder builder, LogEventInfo logEvent)
        {
            dynamic logEntry = new JObject();
            logEntry.TimeStamp = logEvent.TimeStamp.ToString("yyyy-MM-ddTHH:mm:ss.mmmzzz", CultureInfo.InvariantCulture);
            logEntry.TimeStampUtc = logEvent.TimeStamp.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ss.mmmZ", CultureInfo.InvariantCulture);
            logEntry.Level = logEvent.Level.ToString();
            logEntry.LoggerName = logEvent.LoggerName;
            logEntry.Message = logEvent.FormattedMessage;

            foreach (var prop in logEvent.Properties)
            {
                logEntry[prop.Key.ToString()] = prop.Value.ToString();
            }
            var json = logEntry.ToString(Formatting.None);
            builder.Append(json);
        }
    }
}

logstash.conf

input { 
   rabbitmq {
    durable => true
    exchange => "logstash"
    codec => json
    host => "localhost"
    passive => false
    password => "guest"
    port => 5672
    prefetch_count => 1
    ssl => false
    # tags => ... # array (optional)
    type => "nlog"
    user => "guest"
    verify_ssl => false
    vhost => "/"
   }
}

filter{
    date{	    
	    match => ["TimeStampUtc", "ISO8601"]
	}
}

output { 
    stdout { codec => rubydebug }
    elasticsearch { embedded => true }
}

web.config

<nlog>
    <extensions>
      <add assembly="NLog.Targets.RabbitMQ" />
      <add assembly="Cats.Middleware.Logging" />
    </extensions>
    <targets async="true">
      <target name="RabbitMQTarget"
               type="RabbitMQ"
               username="guest"
               password="guest"
               hostname="localhost"
               exchange="logstash"
               port="5672"
               topic="logstash"
               vhost="/"
               durable="true"
               appid="Test"
               maxBuffer="10240"
               heartBeatSeconds="3"
               useJSON="false"
               layout="${json}"
                />
      <target name="file" type="File" fileName="${basedir}/logging/loggy.txt" layout="${json}" />
    </targets>
    <rules>
      <logger name="*" minlevel="Debug" writeTo="RabbitMQTarget,file" />
    </rules>
  </nlog>

Having problems implementing a similar thing for my own project. ${json} never gets populated.

Is there anything else, that needs to be in place?
I asked the question on stackoverflow; I re-namespaced it to suite.

http://stackoverflow.com/questions/23710935/nlog-custom-layoutrenderer-json-cant-get-working

Hey, sorry I missed your comment. You have it sorted now?