In this blog post I will try to give you some clues on a question that a lot of people are asking me when talking about Rust:

Chekov

CQRS/ES have been trending topics for some times now and there are some pretty nice libraries out there to build application following these patterns. But I found myself missing some of those tools to build Rust applications for a while so I decided to try to fulfill this gap by implementing it myself.

In this blog series I will cover my way of building an OpenSource framework called Chekov. I will try to describe how I design and implement the whole thing. I will start from scratch, I will fail sometimes, but I will learn a lot and you too. I will try to cover as much part of the reflexion I have, feel free to ask for more details on Twitter or at the end of each blog post.

But you may have a question:

What the f*ck is Chekov ?

Chekov is a Rust framework to help people building CQRS/ES application. It aims to provide everything you need to dispatch a command, produce events and build projections.

Clippy is a nice tool to improve code quality on Rust projects but he has a little issue which is pretty annoying over time.

When clippy run and display errors to fix and you fix a single one or you run cargo check, the next time clippy run he will display no errors anymore. Weird right?

Here’s a simple tricks to make it work again.

I’m currently working on a library and I want it battle tested. I don’t want to reach 100% code coverage but testing is part of the development workflow and moreover Rust natively provides testing and documentation facilities.

But, what’s the point about #[cfg(test)]?

Sometime you try to understand why an assertion failed. It can be many things and you need some visibility to understand what’s wrong with your code.

By default cargo test prevent every print. To display it you just need to use this:

$ cargo test -- --nocapture

Enjoy