This Glitch project is a proof of concept for using Glitch with Rust, and specifically using Rust's Actix web framework to run a simple "Hello World!" backend web application.

It turns out that Glitch and Rust aren't quite a match made in heaven: Glitch containers just don't quite have the "oomph" needed for a smooth compilation experience. Nonetheless, it works! (Mostly.)

Well, building everything from a cold start with no S3 cache will take about an hour. That's... pretty bad.

It's a lot better with an S3 cache present, though! Check out the project's hidden .infra/ directory (on GitHub here: https://github.com/karlmdavis/hello-rust-actix/tree/master/.infra), which has Ansible scripts to setup the caching infrastructure in AWS for you: basically just an S3 bucket that the Glitch app can read from and write to. Once you have that setup, open up the .env file in Glitch and set the AWS_S3_CACHE_BUCKET, AWS_ACCESS_KEY_ID, and AWS_SECRET_ACCESS_KEY variables. After that, the project's install & compile loops drop down to 4 minutes or so, even from a cold start (once you've built things at least once to populate your cache). Yay!

(I mean, it's still not great, but it's at least workable.)

There is one other niggle, though: the cargo/rustc compile cycle uses more than 500 MB of RAM (when there's no cache present). In debug mode, it does seem to eventually sneak past Glitch's process killer and succeed. But I can't reliably get a --release build of the project to succeed

:shrug: Oh well.

The glitch.json file tells when and how to run the glitch/install.sh and glitch/start.sh scripts to power this application.

To keep the project clean and avoid Glitch's 200MB project size limit we do all of our Rust installation, compilation, etc. in the container's /tmp directory.

References that were useful:

• Glitch Forums: Language support on Glitch: a list
• Glitch Help Center: What technical restrictions are in place?
• Glitch Help Center: Can I change which files cause my app to restart?

The project's basic Rust skeleton was created, as follows:

$ cargo new --bin ./hello-rust-actix && mv ./hello-rust-actix/* ./ && rmdir hello-rust-actix
     Created binary (application) `./hello-rust-actix` project

From there, I just followed the basic instructions on https://doc.rust-lang.org/book/ch01-03-hello-cargo.html and https://actix.rs/docs/getting-started/.

This project is in the worldwide public domain. As stated in CONTRIBUTING:

This project is in the public domain within the United States, and copyright and related rights in the work worldwide are waived through the CC0 1.0 Universal public domain dedication.

All contributions to this project will be released under the CC0 dedication. By submitting a pull request, you are agreeing to comply with this waiver of copyright interest.