Rename "runtime" to "engine".

[PiotrSikora]

Signed-off-by: Piotr Sikora [email protected]

[PiotrSikora]

This has been bugging me for a while, since Proxy-Wasm C++ Host is the runtime, so the other things must be something else... Thoughts?

[mathetake]

this sounds weird to me as engine in general (at least on wasm-c-api layer) means the part of Wasm runtime (wasmtime, wavm, etc) which is the global context per store and in charge of compilation and caches.

[mathetake]

quote from wastime doc https://docs.wasmtime.dev/api/wasmtime/struct.Engine.html :

An Engine which is a global context for compilation and management of wasm modules.

[mathetake]

C++ host IMO is an embedder, not a runtime, so using the word runtime for Wasmtime, V8, etc. sounds reasonable to me, but not strongly objects renaming to engine! Up to you

[PiotrSikora]

C++ host IMO is an embedder, not a runtime, so using the word runtime for Wasmtime, V8, etc. sounds reasonable to me, but not strongly objects renaming to engine! Up to you

Agreed, C++ Host is an embedder of the engine/runtime, but that's not mutually exlusive with either, IMHO.

this sounds weird to me as engine in general (at least on wasm-c-api layer) means the part of Wasm runtime (wasmtime, wavm, etc) which is the global context per store and in charge of compilation and caches.

quote from wastime doc https://docs.wasmtime.dev/api/wasmtime/struct.Engine.html :

An Engine which is a global context for compilation and management of wasm modules.

But that's the part we're referring to here (i.e. engine is the top-level object that manages everything else).

From https://github.com/WebAssembly/wasm-c-api:

Provide a "black box" API for embedding a Wasm engine in other C/C++ applications.

I agree that the terminology is a bit murky, because most of the Wasm engines are included as part of Wasm runtimes, which can start Wasm modules and expose runtime environment for them (WASI, etc.).

But if you look at V8 and JavaScript, it's a bit more clear there:

From https://v8.dev:

What is V8?
V8 is Google’s open source high-performance JavaScript and WebAssembly engine, written in C++.

From https://nodejs.org/en/:

Node.js® is a JavaScript runtime built on Chrome's V8 JavaScript engine.

From https://en.wikipedia.org/wiki/Deno_(software):

Deno is a runtime for JavaScript and TypeScript that is based on the V8 JavaScript engine

From https://github.com/bytecodealliance/wasmtime/tree/main/cranelift:

Wasmtime non-Web wasm engine.

[PiotrSikora]

This article has a good explaination of engine vs runtime, but obviously it's not authoritative:
https://medium.com/@misbahulalam/uncover-the-javascript-engine-vs-runtime-6556ef449634