bumpalo VS jsii

Long story short, heap allocation is painfully slow. Any sort of malloc will always be slower than a custom pool or a bump allocator, because it has a lot more context to deal with.

Rust makes it especially hard to use custom allocators, see bumpalo for example [0]. To be fair, progress is being made in this area [1].

Theoretically one can use a "handle table" as a replacement for pools, you can find relevant discussion at [2].

[0] https://github.com/fitzgen/bumpalo

There are ways to accomplish this as well. Different allocator libraries exist for this kind of scenario, namely bumpallo which allocates a larger block of memory from the kernel, and allocates quickly thereafter. That would amortize the cost of memory allocations in the way I think you're after?

Meaning, storing a lot of things in the same block of allocated memory? Vec is a thing, you know. There's also a bump allocator library.

There are data structures like slotmap, and relatively low-level crates like bumpalo. This is not to say that either fits your use case, just that you definitely have access to the necessary parts to fit what you describe.

Sometimes you can put everything in a bump allocator, then when you're done, free the entire bump allocator in one go. https://docs.rs/bumpalo/

This is useful with crates like bumpalo which give you bump-allocation arenas whose lifetimes are tied to the objects they allocate.

TSC doesn't need to "stick around", right? Just a run-once and the program is over?

In those cases, https://github.com/fitzgen/bumpalo works amazingly as an arena. You can pretty much forget about reference counting and have direct references everywhere in your graph. The disadvantage is that it's hard to modify your tree without leaving memory around.

We use it extensively in http://github.com/dioxusLabs/dioxus and don't need to worry about Rc anywhere in the graph/diffing code.

Probably bumpalo, but then its Box will have a lifetime parameter - bumpalo::boxed::Box<'a, dyn MyTrait>

Strictly speaking, Rust doesn't need this as a built-in language feature, because its design allows it to be implemented as a third-party library: https://docs.rs/bumpalo

The biggest problem is that there's some awkwardness around RAII; I'm not sure whether that could have been avoided with a different approach.

Of course, ideally you'd want it to be compatible with the standard-library APIs that allocate. This is implemented, but is not yet at the point where they're sure they won't want to make backwards-incompatible changes to it, so you can only use it on nightly. https://doc.rust-lang.org/stable/std/alloc/trait.Allocator.h...

Or are you suggesting that the choice of allocator should be dynamically scoped, so that allocations that occur while the bump allocator is alive automatically use it even if they're in code that doesn't know about it? I think it's not possible for that to be memory-safe; all allocations using the bump allocator need to know about its lifetime, so that they can be sure not to outlive it, which would cause use-after-free bugs. I'm assuming that Odin just makes the programmer responsible for this, and if they get it wrong then memory corruption might occur; for a memory-safe language like Rust, that's not acceptable.

What about jsii? The technology behind AWS sdks: https://aws.github.io/jsii/

Is Stainless similar, different?

The libraries for other supported languages of CDK are built as wrappers for underlying JS or maybe TS code via https://github.com/aws/jsii

So all the core CDK code is written first in JS/TS and then stubs for the other languages are added

Unfortunately this is often done without consideration for how the other supported langs actually work, and artefacts of e.g. JS lack of support for kwargs leak through

This is why e.g. the typing in CDK Python is completely broken - pretty much uniformly the concrete types like "Resource" don't implement their corresponding interface like "IResource" (to a type checker)

(There are many other typing niggles like this but that's the most egregious and pervasive one)

At the end of the day, having to explicitly cast concrete types as their interface to satisfy type checker is a minor annoyance, albeit a stupid one that could have been avoided with more care in the core library.

I could live with that, but I encountered so many bugs and issues trying to use CDK on current project that it's now much clearer to me why every company I worked at previously was using Terraform.

Pretty sure some of those issues are ultimately CloudFormation ones. The cumbersome CF > CDK JS > CDK Python stack is great for obfuscating errors and making debugging hard or impossible though.

Pulumi do something similar, albeit with Go as the core language and Terraform underneath. From what I've seen with a little use they have a much more successful result though, Pulumi Python was not a complete mess, and deploys faster and more reliable with better error feedback. I guess they just took more care to get it right.

Every version of the CDK uses an interop layer and runs on top of the Typescript version

https://github.com/aws/jsii

And as far as TF supports services before CFT. Guess which is easier for an AWS employee to do - getting the CF service team to support a new service or just contribute to Terraform’s open source project?

I know of at least one service where the service team introduced the needed APIs and then an employee of AWS wrote the TF provider and contributed to the project before AWS’s own internal team added it to CFT.

Source: former AWS ProServe employee

To "meet developers where they are" is a beautiful tenet of AWS, and of the CDK, and inspired us to create awesome technology such as JSII and constructs.

Yeah both CDKTF and Pulumi piggyback on JSII, a class translator that supports the languages you've mentioned, which was used as a building base for CDK.

The reason we chose to start with compilation to JavaScript and not some other popular cloud language is because JavaScript is currently one of the most used ones, and in addition, we are using JSII to write our SDK in Typescript and then export it for consumption in other languages, such as Go, Python, Java and others.

The CDKTF CLI is implemented in TypeScript. Providers and resources are implemented in TypeScript as well. jsii is used to compile the providers and resources to the supported languages.