In a previous blog post, I discussed a very complex and intricate process: how my family unloads our dishwasher using a chain of responsibility. We examined a happy-path scenario in which each person hands a dish to the next. Every step takes the same amount of time, and the process hums along like clockwork. You can almost hear us singing “Whistle While You Work” while we gleefully put away dishes.

Anybody can write code that will work for a few weeks or months, but what happens when that code is no longer your daily focus and the cobwebs of time start to sneak in? What if it's someone else's code? How do you add new features when you need to relearn the entire codebase each time? How can you be sure that making a small change in one corner won't break something elsewhere? Complexity and coupling in your code can suck you into a slow death spiral toward the eventual Major Rewrite. You can attempt to avoid this bitter fate by using architectural patterns like event-driven architecture. When you build a system of discrete services that communicate via events, you limit the complexity of each service by reducing coupling. Each service can be maintained without having to touch all the other services for every change in business requirements.

During Build 2017, Microsoft released .NET Core 2.0 Preview 1. While we previously determined it was too early to seriously consider adopting .NET Core, with this release we now believe that the current platform can support a comprehensive, reliable, and production-ready version of NServiceBus. As a result, we are happy to say NServiceBus 7 will support .NET Core 2.0 running on any of the supported platforms.

If you're using Azure Storage Persistence and haven't upgraded to NServiceBus 6 yet, get ready for a tremendous performance boost for your application when you do---especially if you make use of sagas.

Welcome back. Over the last few months, the Particular Slack channels have been awash with interesting links, thoughts, and blog posts. Here are the ones that bubbled to the surface.

I'll admit it: I'm a huge fan of The Hitchhiker's Guide to the Galaxy. I've voted for Zaphod Beeblebrox in more than one election and had a cat in college named The Ravenous Bugblatter Beast (Rav, for short). True to her name, she was an adept and ruthless hunter of cockroaches.

Tests are the life blood of many large codebases. They protect you from introducing bugs and in some cases, are instrumental in your code's design. Because of this, maintaining those tests is every bit as crucial as the underlying code that it tests. Like the rest of the project, your tests should be clear, concise, and consistent with your code style. Otherwise, tests might fall into disrepair and end up in a large bucket called technical debt, never to be heard from again.

The new RabbitMQ transport for NServiceBus 6 has one overriding theme: speed. Although we've added a few other features as well, the biggest news is how much faster we've made the new version of the RabbitMQ transport. We've redesigned the message pump to be more efficient, so it can handle more incoming messages. Outgoing messages are sent faster. We've even contributed changes to the official RabbitMQ Client project to increase its performance. Almost everything we've done was focused on making your systems faster and more efficient.

Happy holidays to all of you readers out there! Lately, several of our staff members have been active in the community, sharing valuable insights into building distributed systems. We thought we'd take this opportunity to share some of those resources, as well as other fun stuff, with you. With a bit of async/await, Azure Service Bus, AngularJS, code-driven visualizations, and even a throwback to the Commodore 64, there's something in here for everyone. We hope you enjoy!

.NET Core is out. Officially. After a lot of waiting, it's finally a real, finished, RTM thing, and as developers who are passionate about the .NET ecosystem, we're very excited about it. How cool is it to know that we can write code in C# (or VB.NET, or F#, etc.) and have it run on Windows, Linux, and even macOS? So why on earth doesn't NServiceBus support .NET Core yet? Well, good question.

Many .NET developers have been busy upgrading their code to take advantage of the async and await keywords. These keywords make asynchronous programming a lot easier by allowing us to represent a call to an asynchronous method almost as if it were a synchronous one. We just add the await keyword, and the compiler does the hard work of dividing the method into sections and keeping track of where to resume execution once async work completes. However, it's difficult to hide all the complexity of asynchronous programming behind a couple keywords, and there are a host of pitfalls and gotchas that you should be aware of. Without proper tooling, it's all too easy for any one of them to sneak up and bite you.

In order to support the async/await keywords in NServiceBus 6.0, we had to make the first ever breaking change to the message handler API. We realize that this is a big change, and it's not one that we made lightly. The move to async/await required that the Handle method signature return a Task instead of void. At the same time, we replaced IBus with context-specific parameters to make it clearer which messaging operations are available from within a message handler. In order to make the conversion process as easy as possible, we've prepared a screencast that demonstrates how to convert a message handler from the previous syntax to the async-enabled API in NServiceBus 6.0.

Scaling out a web server is easy. All you have to do is stand up a bunch of web servers behind a load balancer like HAProxy and you're covered. Unfortunately, it hasn't been quite as easy to scale out MSMQ-based NServiceBus systems. That is, until now.

When I make a promise to someone, I do my best to keep it. If I'm pretty sure I won't be able to do something, I don't make any promises about it. Instead, I say I'll try to address it eventually. It's all about managing expectations. In some ways, a promise is like a software interface — a kind of contract between the other person and me. With asynchronous computations, we make promises in software too. They are similar to the promises you and I make, representing operations that haven't happened yet but are expected to happen in the future. In JavaScript, for example, there is an explicit Promise construct. In .NET, this is done with the System.Threading.Task class. Unfortunately, not everyone takes promises seriously — both in real life and in software.

MSMQ was the very first NServiceBus message transport, and while not overly flashy, it got the job done. You could almost call MSMQ a finished product because, while it's updated with each Windows release, it doesn't really change much. It's solid, reliable, dependable, and overall, it Just Works™. One of the biggest changes we made in version 6.0 of NServiceBus (V6) is that the framework is now fully async. The thing is, the MSMQ's API in the .NET Framework hasn't been updated to support async/await, so what could we do for the MSMQ transport in NServiceBus? Make it go faster anyway. That's what.

With the upcoming version 6 of NServiceBus, we bid the IBus interface farewell and in its place, welcome a new wave of context-specific interfaces that are more intuitive and easier to test.

In the 1960s, Shigeo Shingo, a Japanese manufacturing consultant from Saga City, Japan, pioneered the concept of *poka-yoke*, a Japanese term that means "mistake-proofing." In a nutshell, *poka-yoke* involves saving time and cutting waste by reducing the possibility of defects. Although some number of mistakes will always occur, processes can be put in place to catch those mistakes before they turn into actual customer-facing defects. This is a model we've been trying to follow with NServiceBus -- not only with regards to our internal development processes, but also in our efforts to guide developers toward building message-driven systems. Through countless API design decisions over the years, we've been making it ever easier to use NServiceBus the right way and ever more difficult to use it wrongly. This way, developers naturally fall in to a pit of success.

Upon the return from my visit with the newly-discovered Ossian society, it happened that my ship capsized and I was marooned for a time on a tiny deserted island somewhere in the Caribbean Sea. One might think that the biggest problem with being marooned would be finding food for survival, but that was not the case on this island. Coconut and pineapple trees grew all over, and as luck would have it, I stumbled across a hidden cache of rations likely left behind by Spanish explorers or pirates. Among the supplies were dried and preserved meats and a collection of rum in glass bottles. The biggest problem when stranded, after finding food and shelter, is keeping one's own mind occupied. One day, I took a discarded rum bottle, inserted a note, and threw it into the sea.

Have you ever been pulled in to a software project and had to figure out how everything works? Often, your options are limited to either sifting through piles of documentation or diving into thousands of lines of code. Unfortunately, the documentation probably became obsolete as the software grew and evolved and, while the code is accurate by definition, it requires a lot of concentration to trace through and figure out how everything fits together. …

In the spring of that year, my travels brought me upon a previously undiscovered civilization. The people called themselves Ossians, and they lived in an isolated collection of villages in a remote part of South America. Being remote as they were, their level of technology was understandably primitive. But I was surprised by the locals' recent obsession with new forms of communication. It all started, they told me, when one of them discovered that by attaching a rope between two clay pots and stretching the rope taut, a voice uttered into one side could be heard on the other. (I neglected to tell them that even as a boy I had done this very thing with tin cans.)

We've been hard at work on the next major version of NServiceBus for a long time, and we're really excited to show it to you for the first time today! With major improvements in performance, top-to-bottom async support, and an even cleaner API, this version takes NServiceBus to a whole new level. And as of today, NServiceBus 6.0 is now available for public beta.

In 2004, Gregor Hohpe published his brilliant post "Starbucks Does Not Use Two-Phase Commit." When I read it, my time working at Starbucks during my college years suddenly became relevant. Over the years, I gradually realized there's even more that programmers can learn from the popular coffee chain. Although many people may want to build scalable software, it can be much harder than it first appears. As we work on individual tasks, we can fall into a trap, believing all things are equally important, need the same resources, and happen synchronously in a predefined order. It turns out they don't—at least not in scalable systems, and certainly not at Starbucks.

In the second keynote of NSBCon 2015, Ted Neward introduces the concept of Platform-Oriented Architecture (POA) as the logical successor to the currently used SOA/REST architectural approaches. POA is a developer-focused approach that has an established communication backplane, an entity definition, a built in agent model and a set of expectations around various execution topics. Ted also talks about the relationship between POA and operating systems, programming languages, and database engines.