kubectl VS tokio

Check https://github.com/kubernetes/kubectl/issues/151

I have read this issue, and up to now it seems not possible to change the kubectl context via an env var: https://github.com/kubernetes/kubectl/issues/1154

However, I would encourage people to take a look at what the code looks like before assuming the Go developer experience on this was positive. Bear in mind that's just the top level kubectl command and some helper functions, the subcommand definitions take up a several more files split into a few more packages. Then you're still not even done, because code that uses the parsed flags still has to redundantly check things that couldn't be enforced at the type level, something Go folks like to pretend is a good thing for some reason.

kubectl is for sure battle tested, but it involves very Kubernetes specific implementations and is going to be too complicated for the first pointer

> context.Background() is typically only used when one doesn’t care about the result. If you did care about the result, you should be passing the parent context to preserve the circuit breaker timeout in case the operation takes too long.

Not necessarily. You would use context.Background in a test situation. It's also commonly used for short-lived applications like a CLI invocation. You can see kubectl uses context.Background quite a lot: https://github.com/kubernetes/kubectl/search?q=context.backg...

> I think the level of pain you experience from mutable references in Rust depends on if you’re coming from an OOP or FP background. I have a FP background and so the patterns I use to build code already greatly restrict mutation. You can usually change code that updates data immutably (creating a new copy of it) with mutable code in rust because the control flow of your program already involves passing that new version back to the caller which also satisfies the borrow checker in most situations.

There has to be a better solution to needlessly copying data.

This is particularly useful for academic purposes, and makes somehow convinient to get the yaml template of k8s objects. I was looking for this as well due to an upcoming ckad test i have. Unfourtunately due to not being considered best practice the request for it was dismissed. https://github.com/kubernetes/kubectl/issues/1073

I see, apologies, I did misunderstand. This is actually a known race condition between kubectl (or even helm, or any Kube API client) issuing the requests to deploy CRs that depend on CRDs while those CRDs are still being installed on the API server. Simply put, kubectl makes these requests too quickly. There is no solution to this currently aside from deploying CRDs separately from the resources they expose. See this kubectl issue: https://github.com/kubernetes/kubectl/issues/1117, and there are some links in the comments to other issues echoing the same problem in helm and elsewhere.

Go add --no-really-all if you really want it: https://github.com/kubernetes/kubectl

You could take a look at how kubectl actually does it: https://github.com/kubernetes/kubectl/blob/master/pkg/cmd/label/label.go

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).