Not everything you read on the internet is true….

I spend a lot of time searching the web for tutorials, walkthroughs, and examples. So much so, in fact, that “Google Search” could be listed as a top skill on my resume. With that in mind, though, it’s important to remember that not everything you read on the Internet is true, and to take care in how you approach things.

A simple plan

I was trying to create a new ASP.NET / .Net 6 application that I could use to test connectivity to various resources in some newly configured Kubernetes clusters. When I used the Visual Studio 2022 templates, I noticed that the new “minimal” styling was used in the template. This is my first opportunity to try the new minimal styling, so I looked to the web for help. I came across this tutorial on Medium.com.

I followed the tutorial and, on my local machine, it worked like a charm. So I built a quick container image and started deploying into my Kubernetes cluster.

Trouble brewing

When I deployed into my cluster, I kept receiving errors about SQL connection errors. Specifically, that the server was not found. I added some logging, and the connection string seemed correct, but nothing was working.

I thought it might be a DNS error within the cluster, so I spent at least 2 hours trying to determine if there was a DNS issues in my cluster. I even tried another cluster to see if it had to do with our custom subnet settings in the original cluster.

After a while, I figured out the problem, and was about ready to quit my job. The article has a step to override the OnConfiguring method in the DbContext, like this:

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            var configuration = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json")
                .Build();

            var connectionString = configuration.GetConnectionString("AppDb");
            optionsBuilder.UseSqlServer(connectionString);
        }

I took this as necessary and put it in there. But what I glossed over was that this will run every time migrations happen. And the configuration is ONLY pulling from appsettings.json, not from environment variables or any other configuration sources.

That “Oh……” moment

At that point I realized that I had been troubleshooting the fact that this particular function was ignoring the connection string I was passing in using environment variables. To make matters worse, the logging I added that printed the connection string was using the full configuration (with environment variables), so it looked like the value was changing. In reality, it was the value from appSettings.json the whole time.

The worst part: that override is completely unnecessary. I removed the entire function, and my code operates as normal.

No Hard Feelings

Let me be clear, though: as written, the article does a fine job of walking you through the process of setting up an ASP.NET / .Net 6 application in the minimal API styling. My issue was not recognizing how that OnConfiguring override would act in the container, and then bouncing around everywhere to figure it out.

I will certainly be more careful about examining the tutorial code before traipsing around in Kubernetes command lines and DNS tools.