Feat/opentracing (#1243)

docs/features/tracing.rst

@@ -1,8 +1,41 @@
 Tracing
 =======
 
-This page details how to perform distributed tracing with Ocelot. At the moment we only support Butterfly but other tracers might just work without
-anything Ocelot specific.
+This page details how to perform distributed tracing with Ocelot. 
+
+OpenTracing
+^^^^^^^^^^^
+
+Ocelot providers tracing functionality from the excellent `OpenTracing C# <https://github.com/opentracing/opentracing-csharp>`_ project. The code for the Ocelot integration
+can be found `here <https://github.com/ThreeMammals/Ocelot.Tracing.OpenTracing>`_.
+
+The example below uses `Jaeger C# <https://github.com/jaegertracing/jaeger-client-csharp>`_ client to provide the tracer used in Ocelot.
+
+.. code-block:: csharp
+
+    services.AddSingleton<ITracer>(sp =>
+    {
+        var loggerFactory = sp.GetService<ILoggerFactory>();
+        Configuration config = new Configuration(context.HostingEnvironment.ApplicationName, loggerFactory);
+
+        var tracer = config.GetTracer();
+        GlobalTracer.Register(tracer);
+        return tracer;
+    });
+
+    services
+        .AddOcelot()
+        .AddOpenTracing();
+
+Then in your ocelot.json add the following to the Route you want to trace..
+
+.. code-block:: json
+
+      "HttpHandlerOptions": {
+            "UseTracing": true
+        },
+
+Ocelot will now send tracing information to Jaeger when this Route is called.
 
 Butterfly
 ^^^^^^^^^