cargo-watch VS tokio

I used cargo-watch here so that every time my source changes, the server will automatically restart and re-serve the updated code.

watch-one-test test_name: # More info on cargo test: https://doc.rust-lang.org/cargo/commands/cargo-test.html # More info on cargo watch: https://github.com/watchexec/cargo-watch cargo watch -x check -x 'test -- --test-threads=1 --nocapture {{test_name}}' -c -q

Rust: RPDS https://docs.rs/rpds/latest/rpds/ and Im https://docs.rs/im/latest/im/

Rust isn’t great for letting you do FP things like other languages, but it does have the best type system imho which makes it the leading functional programming language right now imho. If you’re not using too many specialized python packages then I recommend using Rust instead, even for toy demos, as you can be more confident your code works without needing to run it and wait for a crash like you would in debugging python, and the tests also run faster in rust due to the incremental compilation. Use cargo-watch and you can retest your code every time you save your work.

https://github.com/watchexec/cargo-watch

I usually write a make command to cargo watch and rerun each test file : code file pair independently so then you won’t rerun your tests in other modules when you change the one you work on (faster but might miss stuff if you change API contracts which touch other parts of your codebase)

you can use cargo-watch to real time run tests on save in your attached vs code console session which is about as close to what you're asking as I think exists for rust

Note that cargo, by virtue of being a package manager for a programming language, is primarily going to be dealing with library packages. That's not because it can't manage executables (see cargo-watch for a particularly useful example), it's just that it's less common.

Also check out cargo-watch -- https://crates.io/crates/cargo-watch

Unless there's a new issue, I think this is what was here: https://github.com/watchexec/cargo-watch/issues/249

A feature that I look for whenever possible in my development environment is Hot Reload, with it, every time a file is changed and saved the application restarts, so the cycle of writing-evaluating-refactoring code becomes extremely fast, for Rust, we have cargo watch, I suggest taking a look at the documentation for more details.

Being able to control nondeterminism is particularly useful for testing and debugging. This allows creating reproducible test environments, as well as discrete-event simulation for faster-than-real-time simulation of time delays. For example, Cardano uses a simulation environment for the IO monad that closely follows core Haskell packages; Sui has a simulator based on madsim that provides an API-compatible replacement for the Tokio runtime and intercepts various POSIX API calls in order to enforce determinism. Both allow running the same code in production as in the simulator for testing.

tokio / hyper / toml / serde / serde_json / json5 / console

tokio - An asynchronous runtime for Rust

3. Tokio

The AWS SDK makes use of the async capabilities in the Tokio library. So when you see async in front of a fn that function is capable of executing asynchronously.

Petar is also looking at implementing concurrency the way it is in Go to have a fully functional virtual machine as it is in the spec. This would likely attract more external contributors to developing the VM. One advantage of Rust is that, with the concurrency model, there is already an extensive library called Tokio which he can use. Petar stresses that this isn’t easy, but he believes it’s achievable, at least as a research topic around determinism and concurrency.

Another thing to point out is that async is a thing in Rust. I'm not going to begin to dive into this paradigm in this article, but know it's handled by the awesome Tokio framework.

So I started by using Tokio, a popular async runtime. The docs and samples helped me get a simple outbound TCP connection working. The Rust async book also had a lot of good explanations, both practical and digging into the details of what a runtime does.

Regarding the quote:

> The Original Sin of Rust async programming is making it multi-threaded by default. If premature optimization is the root of all evil, this is the mother of all premature optimizations, and it curses all your code with the unholy Send + 'static, or worse yet Send + Sync + 'static, which just kills all the joy of actually writing Rust.

Agree about the melodramatic tone. I also don't think removing the Send + Sync really makes that big a difference. It's the 'static that bothers me the most. I want scoped concurrency. Something like <https://github.com/tokio-rs/tokio/issues/2596>.

Another thing I really hate about Rust async right now is the poor instrumentation. I'm having a production problem at work right now in which some tasks just get stuck. I wish I could do the equivalent of `gdb; thread apply all bt`. Looking forward to <https://github.com/tokio-rs/tokio/issues/5638> landing at least. It exists right now but is experimental and in my experience sometimes panics. I'm actually writing a PR today to at least use the experimental version on SIGTERM to see what's going on, on the theory that if it crashes oh well, we're shutting down anyway.

Neither of these complaints would be addressed by taking away work stealing. In fact, I could keep doing down my list, and taking away work stealing wouldn't really help with much of anything.

The PHP <-> Rust bindings are provided by https://github.com/Nicelocal/ext-php-rs/ (our fork of https://github.com/davidcole1340/ext-php-rs with a bunch of UX improvements :).

php-tokio's integrates the https://revolt.run event loop with the https://tokio.rs event loop; async functionality is provided by the two event loops, in combination with PHP fibers through revolt's suspension API (I could've directly used the PHP Fiber API to provide coroutine suspension, but it was a tad easier with revolt's suspension API (https://revolt.run/fibers), since it also handles the base case of suspension in the main fiber).