Full source code available here.
I recently hit a problem where I was getting incorrect responses from a server behind a load balancer. Looking at the logs didn’t help because there was no error.
It was likely due to a misconfigured environmental variable but I couldn’t even identify which server was having the problem because of the load balancer.
Luckily the application was a .NET Core Web Api and I could use a little bit of middleware to add the server name to the response header.
It’s a trivial change in the Configure(..) method of Startup.cs
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
app.Use((context, next) =>
{
context.Response.Headers.Add("MachineName", $"{Environment.MachineName}");
return next();
});
app.UseMvc();
}
That’s all I had to do.
Here’s how the response looks now.
Image may be NSFW.
Clik here to view.
.
Full source code available here.
