Impress your colleagues with your knowledge about…Environment.FailFast

Sometimes when working with .NET you discover some hidden gems. Some of them very useful, other ones a little bit harder to find a good way to benefit from their functionality. One of those hidden gems that I discovered some days ago is Environment.FailFast.

The FailFast method stops your program immediately, ensuring that no further code can execute. As this means that you cannot report the problem directly to the user, this static method includes a parameter, to which you can provide a string containing a status message. This message is recorded in the application event log.

When is this method useful?

One scenario where this method is useful is when your program can enter an unstable state that introduces the risk of data corruption. If this means that it is not possible to continue with the process safely, it may be necessary to exit the program and report an error. Environment.FailFast allows you to kill the process immediately, ensuring that no further code executes.

Another scenario where you can use it is when you have an application that is giving you some weird output. You know it's wrong, but there are just no exceptions bubbling to the surface to help you out. By putting Environment.FastFail you can log an internal exception and hopefully find out where your problem is.

Here is a code sample:

Notice that when you execute this code, only the ‘start’ message is written to the console.

Podman– Command execution failed with exit code 125

After updating WSL on one of the developer machines, Podman failed to work. When we took a look through Podman Desktop, we noticed that Podman had stopped running and returned the following error message: Error: Command execution failed with exit code 125 Here are the steps we tried to fix the issue: We started by running podman info to get some extra details on what could be wrong: >podman info OS: windows/amd64 provider: wsl version: 5.3.1 Cannot connect to Podman. Please verify your connection to the Linux system using `podman system connection list`, or try `podman machine init` and `podman machine start` to manage a new Linux VM Error: unable to connect to Podman socket: failed to connect: dial tcp 127.0.0.1:2655: connectex: No connection could be made because the target machine actively refused it. That makes sense as the podman VM was not running. Let’s check the VM: >podman machine list NAME ...

Cache stampede: when our cache turned against us

While investigating some performance issues, we ran into an ASP.NET Core API that cached a fairly expensive aggregation query for 60 seconds. Under normal load, that was fine: one request rebuilds the cache, everyone else reads from it. Under peak load, dozens of requests would arrive in that same expiry window, all see a cache miss, and all fire the same expensive query in parallel. The database didn't like that. That was the moment when our caching layer stopped helping and started hurting. A burst of requests comes in at the same time, all miss the cache, and all go hammer the database or the downstream API at once. That's a cache stampede . The cache was supposed to protect our backend, and for a few hundred milliseconds it did the opposite. Why this happens IMemoryCache.GetOrCreate (and its async sibling) looks like it protects you, but it doesn't add any locking on its own. Look at the naive version: public async Task<Report> GetReportAsync(string key) ...

The role of ActivitySource in OpenTelemetry for .NET

While doing some pair programming to integrate OpenTelemetry tracing to a .NET application, we had a discussion on how to use the ActivitySource . It looks simple. You new one up, give it a name, start an activity, done. The discussion started when we added a second ActivitySource with the exact same name in a different class. This made us wonder: "Are we duplicating traces now? Is this a memory leak? Do we need a singleton?" So we decided to dig deeper. This post is what we learned… What ActivitySource actually is ActivitySource is part of System.Diagnostics , not part of the OpenTelemetry NuGet packages. Microsoft built tracing primitives directly into the BCL, and OpenTelemetry's .NET SDK simply listens to them. This is why you can add distributed tracing to a library without taking a dependency on OpenTelemetry at all. An ActivitySource is a factory for Activity objects, and an Activity is .NET's name for what OpenTelemetry calls a span.(don’t ask m...

The art of simplicity

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