Please forgive the tangent, but I'm curious about how people are using Rust if it's not in their primary day job? My impression is that there aren't yet many Rust jobs, but many practitioners. What are people building with it? For Rust enthusiasts, how do you use it? Are you contributing to an open source project or do you have your own pet projects? In either case, what are the projects? I'm asking because I might have some time to play around with it over break.
Even if you're not working in a rust company if you have some leeway you can use rust anyway for non-critical parts.
E.g. I have written a cache-warmer that preopens and does readaheads (posix_fadvise) for assets from NFS and offers the already open file descriptors to the calling process. The NFS share offers decent throughput but terrible latency (compared to NVMe). Opening files is slow, walking directories sequentially is slow. And then hitting cold pages is slow. Doing all this in rust and handing the file descriptors over to node lets me reduce minutes to seconds. But if someone doesn't like it, there's a flag that turns it all off, back to the slow path.
Another use is essentially replacing shell-scripting when some REST APIs, JSON parsing and so on are involved. E.g. to glue together some status reporting in CI. There are so many different unreliable APIs without client libs involved that I appreciate the error handling.
We're using Rust for general purpose APIs. What would normally be written in Python or Go, for us. We just prefer it. We're also using it for a couple memory/generic intensive applications that were previously written in Go, but the lack of Generics made some API design awkward.
I use it for all my personal projects as well. Which are basically the same types of things I wrote in Go. Though, I also am experimenting with WASM DOM UIs, something I've not yet used in Go.
People are using rust as they do other general purpose programming languages that have somewhat of a focus on systems programming: to write code. Your question isn't really easy to answer in the same way that someone asking "what are people building with python?" isn't useful. The answer is everything from webpages to text editors to operating systems, and everything in between.
Programming languages lend themselves to different applications and the kinds of projects one contributes to in one's hobby time are different than those one contributes to in one's professional time. As such, I wouldn't expect hobbyist Rust users to work on the same distribution of projects as professional Python developers. In any case, I just want to know what people are inspired to work on with Rust; it's an open ended question, and it's okay that this question has no single easy answer. (Also, "what are people building with Python?" is a very interesting question to me; it's pretty much why https://github.com/trending?l=python and similar exist--and note, the kinds of projects that trend for Python are very different from those that trend for Rust).
I've been using it as a way to learn some of the fundamentals of my field and write packages from other languages in Rust as a learning exercise. Then once those reach some level of usability / goodness, I've started building small CLI's for $work.
I have a feeling that inside of 5 years Rust will be blowing up on the job market. It's just so good and so practical that once you pick it up, anything less well designed will feel like a kludge and hack that might blow up on you at any point.
I use it for essentially every programming task, with the exception of using matplotlib to generate figures. I've personally used Rust in all of these areas to some extent: APIs, data processing, blackjack engine, operating systems, bioinformatics, etc.
My current pet project in Rust is writing a functional language compiler that compiles down to System F/F omega and eventually I'm going to build some kind of virtual machine
I use rust for commercial projects because I can specify the language and sometimes rust is the right language (most of the time python is the right language). I was hired into this role many years ago as a PHP developer. And we haven't needed rust devs. So I have no experience with the rust job marketplace.
I also have a lot of personal pet projects written in rust: an MMORPG-style game, accounting software, various WASM widgets, some OS fiddling, some work extending servo as a browser that implements umatrix-like control but lets you set options per domain (e.g. 3rd party cookie, user agent setting, etc, all per-domain).
I've also contributed a number of small libraries that I wrote for my projects to open source (textnonce, float-cmp, mailstrom, formdata, mime-multipart, solvent, ddsfile, pemmican, resolv-rs, email-format, and others).
We're using it for a lot of non-critical stuff, and a few small semi-critical jobs. It's useful training to re-implement system test utilities in Rust, for example, then extend them once they work. Rust makes some things much easier (getting a backtrace on error, compared to C++ :)
