async-std VS embassy

But maybe check out the discussion here https://github.com/async-rs/async-std/pull/631 or something (the blog post was linked on the end of it)

Have a look at these: https://github.com/async-rs/async-std/tree/main/examples

In fact, there are a lot of crates in Rust where in other programming languages, it would be included in the standard library. Examples are regex, random number generators, additional iterator methods, macros for other collections, num traits, loggers, HTTP libraries, error handling, async runtimes, serialization and deserialization, date and time, and many more.

Two major projects (non std lib but extremely commonly used) stand out in the area of async programming: Async std and Tokio - no doubt familiar to anyone that has turned an eye towards Rust for a second too long. Async architecture in general is likely very familiar to JavaScript programmers but in Rust there are some extra considerations (like ownership of the data that is thrown into an async function). Tokio is fast becoming a heavily supported and road tested async framework, with a thread scheduling runtime "baked in" that has learned from the history of Go, Erlang, and Java thread schedulers.

Ah... https://github.com/tokio-rs/tokio and https://github.com/async-rs/async-std ?

async-std: Basically a Tokio alternative with a few different design decisions.

Go's solution is for the scheduler to notice after a while when a goroutine has blocked execution and to shift goroutines waiting their turn to another thread. async-std pondered a similar approach with tasks, but it proved controversial and was never merged.

This indicates curl, zlib, openssl, and libnghttp2 as well as a bunch of WASM-related things are being dynamically linked into my executable. To resolve this, I looked at the build features exposed by surf and found that it selects the "curl_client" feature by default, which can be turned off and replaced with "h1-client-rustls" which uses an HTTP client backed by rustls and async-std and no dynamically linked libraries. Enabling this build feature removed all -sys dependencies from androidx-release-watcher, allowing me to build static executables of it.

And also, the actual PR never got merged.

Async in rust needs a runtime (aka executor) to run. You can maybe get a better description from the rust docs. As an example, Tokio attempts to provide an interface for a developer that is minimal change to the more common blocking code. So you'd end up putting #[tokio::main] above your main function to spin up the executor and most of the rest of the code is similar to a non-async version with a few sprinkles of .await, which you can see in the hello world for tokio. In contrast, async-std provides a more hands-on/low-level approach. If you are unlucky enough to have libraries that choose different stacks to work on, you'll possibly (probably?) have to handle both.

thanks. looked that up. for the curious: https://embassy.dev/

Running the Embassy RP2040 USB CDC ACM serial example takes about 5 seconds on a Pico.

https://github.com/embassy-rs/embassy/blob/main/examples/rp/...

Async solves different problems, you can, for instance, have just a single-threaded CPU and still have a nice API if you have async-await. It might not be so cool at a higher level as Go's approach of channels and threads, but it's cool in embedded, read this:

https://github.com/embassy-rs/embassy?tab=readme-ov-file#rus...

"Rust's async/await allows for unprecedently easy and efficient multitasking in embedded systems. Tasks get transformed at compile time into state machines that get run cooperatively. It requires no dynamic memory allocation, and runs on a single stack, so no per-task stack size tuning is required. It obsoletes the need for a traditional RTOS with kernel context switching, and is faster and smaller than one!"

I'm just toying with Raspberry Pi Pico and it's pretty nice.

Go and Rust have different use cases, the async-await is nice at a low level.

I have not yet dipped by toes in the Rust waters, but reading about the embassy project is actually what piqued my curiosity about using C++ coroutines in embedded. Are you familiar with the project or have you found it lacking?

I think I get the basics (shoutout to the Rust Embedded Working Group!), and I've started looking for the stack I'd be using. I think Embassy is really amazing, as well as the work of the ESP team -- hats off.

> }

And this is how to do it using embassy, which is an async framework for embedded in rust:

https://github.com/embassy-rs/embassy/blob/main/examples/rp/...

> not good for embedded

embassy begs to differ

https://embassy.dev/

async/await is really just a syntax for building state machines in a way that resembles regular code. It's compiled down to the same code that you would write by hand anyway (early on it had some bloat in state size but I think it's all fixed now).

And embedded has a lot of state machines!

You can run multiple executors at different interrupt priority levels (with multiple tasks per executor), which allows tasks on the higher priority executor to interrupt other tasks. Here's an example https://github.com/embassy-rs/embassy/blob/main/examples/nrf...