Embedded Rust in Production?

I recently finished a contract at a (very large game dev) company where some tools were written in Rust. The tools were a re-write of python scripts and added no new functionality but were slightly faster in Rust.

The reality was that these tools were unmaintainable by the rest of the company. Only the author "knew" Rust and it was hard to justify a new hire Rust developer to maintain this small set of tools.

The only reason these tools were written in Rust was because the dev wanted to learn Rust (a big but common mistake). I pointed out to the Technical Director that this was a big mistake and the teams had taken on a large amount of technical debt for no reason other than the ego of the wanna-be-rust-developer. Since I "knew" Rust he wanted me to maintain it. My advice was to go back to the Python scripts and I left.

That said, obviously all languages were in that state at some point. Twenty-eight years ago you might have said the same thing about Java. Twenty-four years ago, Perl might have looked like a better choice than Python; now it's clearly the opposite. XenServer took a gamble and wrote their main control stack in OCaml in 2008; on the whole that has had some benefits, but the number of OCaml developers has not significantly grown, and it's not easy to hire people.

That said, I think Rust is much more likely to follow Java's trajectory than OCaml's: My prediction is that it's only going to be easier and easier to find Rust developers.

Viability of a language is certainly a consideration, but the characteristics of the language also matter.

What you couldn't really predict about Java in, say, 2000, was how much the complexity of its ecosystem would grow. In 2000 (or 2005) it was fairly easy to move in and out of Java from project to project. That is not true today. My fear on the Rust front is that it's going to be another C++, where the complexity is considerable and requires more or less full-time expertise.