This blog is part of a series exploring RabbitMQ and MassTransit. Previous episodes are available at
- Creating a RabbitMQ Container
- Getting Started with RabbitMQ in ASP.NET
- MassTransit on RabbitMQ in ASP.NET Core
In the last episode I did a lot of handwaving over the mess I made of configuration. There were hard coded values all over the place. In this article we’ll clear up some of the mess we made.
Docker is now fully sported on Windows 10. In this episode we’ll see what it takes to avoid installing RabbitMQ locally and, instead, use a Windows container. Keeping RabbitMQ in a container allows standing up a cluster on one physical machine, greater ability to experiment and a high degree of isolation. In the future we expect that a great deal of local development will leverage containers.
In the last post, we created an application which can send tasks to a background processor. We did it directly with RabbitMQ which was a bit of a pain. We had to do our own wiring and even our own serialization. Nobody wants to do that for any sort of sizable application. Wiring would be very painful on a large scale.
There are a couple of good options in the .NET space which can be layered on top of raw queues. NServiceBus is perhaps the most well know option. There is, of course, a cost to running NServiceBus as it is a commercial product. In my mind the cost of NServiceBus is well worth it for small and medium installations. For large installations I’d recommend building more tightly on top of cloud based transports, but that’s a topic for another blog post.
In the last post we looked at how to set up RabbitMQ in a Windows container. It was quite the adventure and I’m sure it was woth the time I invested. Probably. Now we have it set up we can get to writing an application using it.
A pretty common use case when building a web application is that we want to do some background processing which takes longer than we’d like to keep a request open for. Doing so would lock up an IIS thread too, which ins’t optimal. In this example we’d like to make our user creation a background process.
I bought a new laptop, a Dell XPS 15 and my oh my is it snazzy. The thing I was most excited about was that I’d get to play with Windows containers again. I have 3 other machines in the house but they’re either unsuitable for containers (OSX running Windows in parallels) or I’ve so toally borked them playing with early betas of containers they need to be formatted and reinstalled - possibly also thrown into the sun.
So when I found myself presented with the question “how can we get into messaging in our apps for free?” I figured I’d crack open the laptop and build something with MassTransit. I found that MassTransit supports running on RabbitMQ. Why that sounds like a perfect opportunity to deploy RabbitMQ to a container. Only problem was that I didn’t really know how to do that.
I want so hard to like docker, but docker sure doesn’t make it easy. Consider trying to copy a file in a dockerfile to a destination with a space in it. You’re likely to get an error about how a path doesn’t exist. If you Google this problem you get great adivce which basically adds up to “Don’t put spaces or whitespace in your file paths”. Thanks.
There are two approaches to putting spaces or whitespace in that I’ve found. The first is to use a variable
ENV PATH_WITH_SPACE "c:/program files/"
The other is to use this insane quasi-json syntax
COPY ["thisisdumb.txt", "c:/program files/"]
Take your pick.
In today’s episode, Monster Dave prototypes an approach to generating static resource URLs to potentially improve the performance of an ASP.NET Core application. Borrowing ideas from a recent blog post by the Facebook engineering team.
First, we create a tag helper to generate static resource URLs based on a hash of the file’s contents. Next, we write some custom middleware to rewrite those new URLs to the actual file and to always return 304 not-modified for all conditional requests.
The Blog Post: https://code.facebook.com/posts/557147474482256
NOTE: This video is intended to explore the concepts outlined in the blog post above and are not be suited for production use.