Serilog - logging specific properties from request body on error

Question

I tried the following answer:

• https://stackoverflow.com/a/68493795/897326

Namely this:

 options.EnrichDiagnosticContext = (diagnosticContext, httpContext) =>
   {
     // string body = your logic to get body from httpContext.Request.Body
        diagnosticContext.Set("Body", body);
   };

But in my case body is an empty string. My code for reading body from httpContext is based on this solution:

• https://github.com/aspnet/Security/issues/1638#issuecomment-363084402

And it works in my custom middleware that I created for global exception handling. It does not use Serilog though. Just some quick poor man's approach to structured logging via Newtonsoft serialization.

I found this enricher on nuget:

• https://github.com/trenoncourt/serilog-enrichers-aspnetcore-httpcontext

But it seems outdated, and the Serilog syntax has changed since then.

I also checked this related official Serilog ticket which was closed.

• https://github.com/serilog/serilog/issues/1506

Is this workflow of adding custom properties from http request not supported natively by Serilog? Quote from their github repo:

Thanks for raising this. I think copying and modifying https://github.com/serilog/serilog-aspnetcore/blob/dev/src/Serilog.AspNetCore/AspNetCore/RequestLoggingMiddleware.cs will be the simplest way forwards (I agree this is a bit unfortunate

For example, if a request has a field called patientId, log that. Because there are infinite number of ways to log properties from http context, it's fine to ask developer to provide that custom method. But creating a custom middleware for this sounds like an overkill. Also multiple middlewares might not work well together.

Is there a way to log custom properties from http request? I have my own global exception middleware, but not sure how to make it work together with Serilog. Or any other option. Main requirement - custom properties should ONLY be logged in case of an error.

Answer 1

One workaround I found is manually logging the error from my global exception middleware. In Program.cs, remove the following line:

app.UseSerilogRequestLogging();

Then in middleware, add

using Serilog;
// ... some code here, then in catch block
Log.Error("Unhandled exception occured when processing request {@errorRequest}.",
                                                                 errorRequest);
// ... more code, set 500 status and custom props on response

Where errorRequest would contain the necessary properties.