Correlations IDs are used in distributed applications to trace requests across multiple services. This library and package provides a lightweight correlation ID approach. When enabled, request headers are checked for a correlation ID from the consumer. If found, this correlation ID is attached to the Correlation Context which can be used to access the current correlation ID where it is required for logging etc.

Optionally, this correlation ID can be attached to downstream HTTP calls made via a HttpClient instance created by the IHttpClientFactory.

NOTE: While I plan to add a few more features to this library, I believe it is close to feature complete for the scenario it was designed for. I recommend looking at built-in tracing for .NET apps for more complete and automated application tracing.

Change history and release notes.

• .NET Standard 2.0+

Package	NuGet Stable	NuGet Pre-release	Downloads	Travis CI	Azure Pipelines
CorrelationId

You should install CorrelationId from NuGet:

Install-Package CorrelationId

This command from Package Manager Console will download and install CorrelationId and all required dependencies.

All stable and some pre-release packages are available on NuGet.

Inside ConfigureServices add the required correlation ID services, with common defaults.

services.AddDefaultCorrelationId

This registers a correlation ID provider which generates new IDs based on a random GUID.

Register the middleware into the pipeline. This should occur before any downstream middleware which requires the correlation ID. Normally this will be registered very early in the middleware pipeline.

app.UseCorrelationId();

Where you need to access the correlation ID, you may request the ICorrelationContextAccessor from DI.

public class TransientClass
{
   private readonly ICorrelationContextAccessor _correlationContext;

   public TransientClass(ICorrelationContextAccessor correlationContext)
   {
	  _correlationContext = correlationContext;
   }

   ...
}

See the sample app for example usage.

Full documentation can be found in the wiki.

It appears that a regression in the code for ASP.NET Core 2.2.0 means that setting the TraceIdentifier on the context via middleware results in the context becoming null when accessed further down in the pipeline. A fix is was released in 2.2.2.

A workaround at this time is to disable the behaviour of updating the TraceIdentifier using the options when adding the middleware.

If this library has helped you, feel free to buy me a coffee or see the "Sponsor" link at the top of the GitHub page.