OpenTelemetryTraceListener 0.12.0

OpenTelemetry Trace Listener

This repository provides a trace listener for OpenTelemetry, a set of APIs and libraries used to achieve distributed tracing and observability within applications. The trace listener enables you to capture and transmit trace data from System.Diagnostics traces and logs to various backends for analysis and monitoring.

Installation

To integrate the OpenTelemetry Trace Listener into your .NET Framework project, install the package via NuGet by running the following command in the NuGet Package Manager Console:

Install-Package Diagnostics.OpenTelemetry

Usage with System.Diagnostics

To configure the OpenTelemetry Trace Listener, add it to the system.diagnostics section in your App.config or Web.config file:

<configuration>
  <system.diagnostics>
    <trace>
      <listeners>
        <add name="OpenTelemetryTraceListener" type="Diagnostics.OpenTelemetry.OpenTelemetryTraceListener, Diagnostics.OpenTelemetry" />
      </listeners>
    </trace>
  </system.diagnostics>
</configuration>

After configuration, you can log trace information using the System.Diagnostics.Trace class. The OpenTelemetry Trace Listener will capture these traces and send them to the specified backend.

using System.Diagnostics;

public class Program
{
    public static void Main()
    {
        Trace.WriteLine("This is a trace message.");
        Trace.TraceInformation("This is an informational message.");
        Trace.TraceWarning("This is a warning message.");
        Trace.TraceError("This is an error message.");
    }
}

Example: Logging to Seq

To log your existing System.Diagnostics traces to a Seq server, follow the steps below.

1. Install the necessary OpenTelemetry NuGet packages:

   Install-Package OpenTelemetry.Exporter.Console
   Install-Package OpenTelemetry.Exporter.OpenTelemetryProtocol
   Install-Package OpenTelemetry.Instrumentation.AspNet -Version 1.9.0-beta.1
   Install-Package OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule -Version 1.9.0-beta.1
   Install-Package Diagnostics.OpenTelemetry
   

2. Add the trace provider to the Application_Start event in your application:

   private TracerProvider _tracerProvider;
   
   protected void Application_Start(object sender, EventArgs e)
   {
       var endpoint = ConfigurationManager.AppSettings["OpenTelemetry:EndPoint"] ?? "http://localhost:5341";
       var apiKey = ConfigurationManager.AppSettings["OpenTelemetry:ApiKey"] ?? "";
       var sourceName = ConfigurationManager.AppSettings["OpenTelemetry:SourceName"] ?? "Web";
   
       _tracerProvider = Sdk.CreateTracerProviderBuilder()
           .AddAspNetInstrumentation()
           .SetResourceBuilder(
               ResourceBuilder.CreateDefault()
                   .AddService(serviceName: sourceName))
           .AddSource($"{sourceName}.Logs")
           .AddConsoleExporter()
           .AddOtlpExporter(options =>
           {
               options.Endpoint = new Uri($"{endpoint}/ingest/otlp/v1/traces");
               options.Protocol = OtlpExportProtocol.HttpProtobuf;
               options.Headers = $"X-Seq-ApiKey={apiKey}";
           })
           .Build();
   }
   

3. Update your Web.config to include the shared listener within the system.diagnostics section, and assign it to the sources you wish to log:

   <system.diagnostics>
       <sharedListeners>
           <add name="OpenTelemetryTraceListener" type="Diagnostics.OpenTelemetry.OpenTelemetryTraceListener, Diagnostics.OpenTelemetry" />
       </sharedListeners>
       <sources>
           <source name="Bus" switchValue="All">
               <listeners>
                   <clear />
                   <add name="sqldatabase" />
                   <add name="OpenTelemetryTraceListener" />
               </listeners>
           </source>
           <source name="Web" switchValue="Information,Warning,Error,Critical">
               <listeners>
                   <clear />
                   <add name="sqldatabase" />
                   <add name="OpenTelemetryTraceListener" />
               </listeners>
           </source>
       </sources>
       <trace autoflush="true" indentsize="0">
           <listeners>
               <clear />
               <add name="OpenTelemetryTraceListener" type="Diagnostics.OpenTelemetry.OpenTelemetryTraceListener, Diagnostics.OpenTelemetry" />
           </listeners>
       </trace>
   </system.diagnostics>
   

4. Ensure proper disposal of the trace provider during application shutdown:

   protected void Application_End(object sender, EventArgs e)
   {
       _tracerProvider?.Dispose();
   }
   

Contributing

We welcome contributions to improve this project. Please feel free to submit issues, pull requests, or feature suggestions.

License

This project is licensed under the MIT License.