wasmtime

The roadmap I linked above. The WASI folks have done a poor job at communicating, no doubt. Just for you I did some googling: see here[0] for the current status of WASI threads overall, or here[1] and here[2] for what they are up to with WASI in general. In this PR[3] you can see they enabled threads (atomic instructions and shared memory, not thread creation) by default in wasmtime. And in this[4] repository you can see they are actively developing the thread creation API and have it as their #1 priority. If folks want to use WASIX as a quick and dirty hack to compile existing programs, then by all means, have at it! I think that's great. Just know that your WASIX program isn't going to run natively in wasmtime (arguably the best WASM runtime with the strongest long-term outlook), nor will it run in browsers, because they're going to fol

Thanks for the question! Spin could definitely run in more places than what we have pre-built binaries for. Specifically, we could run on all platforms Wasmtime supports today (https://github.com/bytecodealliance/wasmtime/releases/tag/v1...), including RISC and S390X, for example. And while we have been experimenting a bit with running Spin on RISC, we haven't really had the bandwidth or requirement to build a production build for those yet. Are you interested in a specific operating system or CPU architecture? Would love to understand your scenario.

> I used to think we'd eventually get to capability based security, but now I see we'll always be stuck with application permission flags, the almost worthless bastard cousin, instead. My hope is that WASI will introduce capability based security to the mainstream on non-mobile computers [0] - it might just take some time for them to get it right. (And hopefully no half-baked status-quo-reinforcing regressive single-runtime-backed alternatives win in the meantime.) [0]: https://github.com/bytecodealliance/wasmtime/blob/main/docs/...

There don't seem to be many write-ups on this concept. The best reference seems to be existing implementations: Wasmer's implementation of metering[0] just traps when it runs out of fuel. WasmEdge's implementation of interruptibility[1] checks a flag and stops execution if it's set. While neither of these support resuming execution after the deadline, replacing the halt with a call to a signal dispatcher should work. Wasmtime has two different implementations of interrupting execution that both support resuming[2]. The fuel mechanism[3] is deterministic but the epoch mechanism[4] is more performant. If you're free to pick your runtime, I'm sure you could configure Wasmtime into doing what you want. [0]: https://github.com/wasmerio/wasmer/blob/master/lib/middlewar... [1]: https://github.com/WasmEdge/WasmEdge/pull/910 [2]: https://docs.rs/w

Well, "now" and "has" ... There is a GC proposal: https://webassembly.github.io/gc/core/ V8 implemented it some months ago (ChromeNode and I guess Deno, with a experimental switch to enable support). WasmEdge isn't there yet: https://github.com/WasmEdge/WasmEdge/issues/1122#issuecommen... WasmTime finished the RFC for the implementation details in June: https://github.com/bytecodealliance/wasmtime/issues/5032

Take your pick of runtimes. Wasmtime is the most popular right now. https://github.com/bytecodealliance/wasmtime/blob/main/docs/...

re LLVM: Yes, Cranelift was designed to address these issues https://github.com/bytecodealliance/wasmtime/blob/main/crane... https://blog.benj.me/2021/02/17/cranelift-codegen-primer https://jason-williams.co.uk/posts/a-possible-new-backend-fo... https://news.ycombinator.com/item?id=25130528 30% faster rust build time

As I understand it, WASI doesn't break all security, or at least not by default. Here's a document about capabilities-based design: https://github.com/bytecodealliance/wasmtime/blob/main/docs/...

No longer does Wasm/WASI need JS host! There are many spec-compliant runtimes built for environments from tiny embedded systems up to beefy arm/x86 racks: - https://github.com/bytecodealliance/wasm-micro-runtime - https://github.com/bytecodealliance/wasmtime - https://github.com/wasmerio/wasmer - https://github.com/tetratelabs/wazero - https://github.com/extism/extism (disclaimer, my company's project - makes wasm easily embeddable into 16+ programming languages!)

There are a few, but I suspect the most widely used would be wasmtime. It's written in Rust and can be used from Go [2] but requires CGo (as mentioned by GP). [1] https://github.com/bytecodealliance/wasmtime [2] https://github.com/bytecodealliance/wasmtime-go

Assuming you are serious, there is https://github.com/bytecodealliance/wasmtime/tree/main/crane... which is written in Rust and is targeted to become the default debug backend in rustc. LLVM has accumulated a lot of optimizations contributed by various groups and people over more than a decade. It's hard to catch up to that by virtue of resource limits.

WASI has been in Preview1 for a couple of years now, indeed. However, Preview2 is well underway and the initial implementation is scheduled to land in wasmtime this June. https://github.com/bytecodealliance/wasmtime/issues/6370

WMWare labs [1] managed to compile Python/Ruby/PHP into WASM distributions. This works if you want to run the language interpreter but is limited when you want your WASM runtime to run in parallel of your own program. This leads to the creation of the "reactor" concept by the community [2]. In the python WASI reactor, we load the libpython compiled for WASM and add a Rust reactor layer. Currently, it supports dynamic registration of Python lambdas and we are working on adding support for whole functions/packages. [1] https://github.com/vmware-labs/webassembly-language-runtimes [2] https://github.com/bytecodealliance/wasmtime/blob/main/docs/...

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