How does Serilog calculate Elapsed in Web API?-CodePudding

For Web API in .NET 6, I'm configuring Serilog request logging.

app.UseSerilogRequestLogging(options =>
{
    options.MessageTemplate = "Elapsed: {Elapsed:0.0000} ms";
});

How is Elapsed calculated exactly?

CodePudding user response：

Serilog has custom RequestLoggingMiddleware which is injected into pipeline via UseSerilogRequestLogging call (that's why it is important to call this method as early as possible cause otherwise it will not take into account time consumed by components that appear before it in the pipeline, as mentioned in the docs). The implementation is pretty straightforward - sample time at the start of logging middleware, invoke the rest of pipeline, sample time at the end, calculate the difference. Currently calculation looks somewhat like this:

var start = Stopwatch.GetTimestamp();

var Elapsed = GetElapsedMilliseconds(start, Stopwatch.GetTimestamp());

static double GetElapsedMilliseconds(long start, long stop)
{
    return (stop - start) * 1000 / (double)Stopwatch.Frequency;
}