Easy Performance and Query Logging in ASP.NET with Serilog and MiniProfiler

Published on Monday, July 13, 2015

I've been playing around with Serilog and have been really, really impressed. If you're not familiar with it, Serilog provides a very nice logging API with the ability to log entire object graphs in addition to flag messages. It's also really extensible and has a lot of community support.

It was very easy to integrate Serilog into my ASP.NET MVC application with SerilogWeb.Classic, but I found myself wanting a little more information. Specifically, I would love to get a log of performance metrics and database queries (I use Entity Framework) that could be correlated with my other logging information. I could always set up timers on the request and hook into the Entity Framework pipeline for this, but I've already spent the time to instrument my important code with MiniProfiler. What I really wanted was a way to take the information I get from MiniProfiler and write it to Serilog.

It turns out that with a little digging, this is pretty easy. First, we'll need a way to get the data out of MiniProfiler. The best I could find is to call MiniProfiler.ToJson() after calling MiniProfiler.Stop(). This outputs a JSON string with the complete set of MiniProfiler data including all subtimings and database queries (which you get if you're using one of the MiniProfiler Entity Framework extensions like MiniProfiler.EF6).

Since JSON is structured and Serilog likes structured data, the next question was how to get this data into Serilog in a format that maintains the structure? Thankfully someone has already written a Serilog extension to do exactly that. Destructurama.JsonNet adds destructuring support for JSON.NET dynamic objects to Serilog. Using this extension, we can easily convert the MiniProfiler JSON string to a JSON.NET object and then feed it into Serilog.

The final code looks like this:

public class MvcApplication : System.Web.HttpApplication
{
    protected void Application_Start()
    {
		Log.Logger = new LoggerConfiguration()
		    .Destructure.JsonNetTypes()
		    // ...
		
	    // ...
	}
	
	protected void Application_BeginRequest()
    {
        MiniProfiler.Start();
		// ...
    }
	
	protected void Application_EndRequest()
    {
        MiniProfiler.Stop();
        if (MiniProfiler.Current != null && MiniProfiler.Current.Root != null)
        {
            Log
			    .ForContext("MiniProfiler", JsonConvert.DeserializeObject<dynamic>(MiniProfiler.ToJson()))
			    .Verbose("Completed request in {Timing} ms", MiniProfiler.Current.Root.DurationMilliseconds);
        }
		// ...
	}
	
	// ...
}

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