README.md

Tracer.OpenTracing.Fody

Fody plugin based off of tracer for instrumenting code with OpenTracing

Functionality

After setup, you can configure application wide tracing with a simple FodyWeavers.xml file, or you can individually select methods and classes to trace with the included [TraceOn] and [NoTrace] attributes.

It can reduce your code as follows

+[TraceOn(TraceTarget.Public)]
 class Class
 {
   public void Method1()
   {
-    IScope scope = GlobalTracer.Instance
-      .BuildSpan(nameof(Class) + "." + nameof(Method1))
-      .StartActive();
-    try
-    {
       // Do stuff
       this.MethodImpl();
-    }
-    finally
-    {
-      /* Some error logging on the Scope */
-      scope.Dispose();
-    }
   }

   public void Method2()
   {
-    IScope scope = GlobalTracer.Instance
-      .BuildSpan(nameof(Class) + "." + nameof(Method2))
-      .StartActive();
-    try
-    {
       // Do stuff
       this.MethodImpl();
-    }
-    finally
-    {
-      /* Some error logging on the Scope */
-      scope.Dispose();
-    }
   }
   
   private void MethodImpl()
   {
     // Do stuff
   }
 }

Setup

1. Make sure your startup logic is configuring GlobalTracer.Instance via GlobalTracer.Register. If you don't have one ready presently, you can use EventHookTracer as follows. ^ Old news, use https://github.com/opentracing-contrib/csharp-decorators now

   EventHookTracer example

   var eventHookTracer = new EventHookTracer(new MockTracer());
   eventHookTracer.SpanActivated += (sender, eventArgs) => Console.WriteLine("+" + eventArgs.OperationName);
   eventHookTracer.SpanFinished += (sender, eventArgs) => Console.WriteLine("-" + eventArgs.OperationName);
   GlobalTracer.Register(eventHookTracer);

2. Import Tracer.OpenTracing.Fody from nuget

   This will import Tracer.Fody and Tracer, which are needed to manipulate the assembly with tracing instrumentation.

3. Configure Fody to use this tracer Add a FodyWeavers.xml file with the following contents. (This file does not need CopyToOutputDirectory)

   <?xml version="1.0" encoding="utf-8" ?>
   <Weavers>   
     <Tracer adapterAssembly="Tracer.OpenTracing" 
             logManager="Tracer.OpenTracing.LogManagerAdapter" 
             logger="Tracer.OpenTracing.LoggerAdapter" >
        <TraceOn class="none" method="none" />
     </Tracer>
   </Weavers>

4. Configure code to be traced

   Use a combination of the FodyWeavers.xml configuration and Attributes on Classes, Assembly, or individual Methods to signal what elements should be traced. See tracer/basics wiki for details.

   Example 1 - FodyWeavers.xml

   <?xml version="1.0" encoding="utf-8" ?>
   <Weavers>   
     <Tracer adapterAssembly="Tracer.OpenTracing" 
             logManager="Tracer.OpenTracing.LogManagerAdapter" 
             logger="Tracer.OpenTracing.LoggerAdapter" 
             staticLogger="" >
       <!-- Trace all methods on public classes -->
       <!-- Avoid tracing the startup method - e.g. don't trace before you've configured the GlobalTracer.Instance
            so in this case, make sure Main and SetupTracer are marked with [NoTrace] -->
       <!-- ^ not necessary anymore, now it will just Trace.Write that you tried to do a trace without a tracer registered -->
       <TraceOn class="public" method="all" />
     </Tracer>
   </Weavers>

   Example 2 - MyClass.cs

   [TraceOn]
   class Foo
   {
       [NoTrace]
       public static void A()
       {
           B();
           B();
       }
   
       public static void B()
       { // BuildSpan().StartActive() is injected on this line
       } // ActiveSpan.Finish() is injected on this line
   }