bachrc (Feb 21 2023 at 17:16): bachrc (Feb 21 2023 at 17:16):Hi here, I just converted my wasm to a component, and I indeed see that in the wit that wasm-tools told be, it is now asking multiple imports. Like wasi-stderr, wasi-stdio...
And when trying to instantiate with wasmtime, well it panics because apparently, the WASM misses some imports.
https://github.com/bytecodealliance/wasmtime/issues/5830
This is a very similar problem to this issue, but I didn't understand the answer given by pchickey. How can I do the bindings? Thanks in advance
Pat Hickey (Feb 21 2023 at 17:17):A host implementation of those imports is provided over in the preview2-prototyping repo under host/
Pat Hickey (Feb 21 2023 at 17:17):it uses a fork of wasi-common, and its very incomplete and buggy
Pat Hickey (Feb 21 2023 at 17:17):and its rapidly changing
bachrc (Feb 21 2023 at 17:19):Oh I see, so I cannot make the bindings for now? Am I forced to use this?
Pat Hickey (Feb 21 2023 at 17:19):so, you need to depend on that crate, and use its add_to_linker and WasiCommand export like here: https://github.com/bytecodealliance/preview2-prototyping/blob/main/host/src/main.rs
Pat Hickey (Feb 21 2023 at 17:20):but note that you need to depend on the previee2-prototyping wasi-common, not the crates.io wasi-common, so please use a git dependency
Pat Hickey (Feb 21 2023 at 17:21):you can either use the implementation in prototyping's host, or you can write your own using wasmtime's wit bindgen. i dont recommend writing your own because its quite hard
Pat Hickey (Feb 21 2023 at 17:21):but if you need to, it is possible
Pat Hickey (Feb 21 2023 at 17:21):you'll have to follow the general pattern we used in that repo of invoking wasmtime::component::bindgen!() to do so, and then impl all of the traits.
bachrc (Feb 21 2023 at 17:22):Yup, I tried to pull your host project :
[dependencies]
.......
wasmtime = { version = "^6.0.0", features = ["component-model", "async"] }
host = { git = "https://github.com/bytecodealliance/preview2-prototyping" }
But when trying to build, I have a version conflict that I... don't understand o.o
wasmtime_host_test git:(main) ✗ cargo check
Updating crates.io index
Updating git repository `https://github.com/bytecodealliance/preview2-prototyping`
Updating git repository `https://github.com/bytecodealliance/wasmtime`
error: failed to select a version for `wasmtime-fiber`.
... required by package `wasmtime v6.0.0 (https://github.com/bytecodealliance/wasmtime?branch=release-6.0.0#c00d3f05)`
... which satisfies git dependency `wasmtime` of package `host v0.0.0 (https://github.com/bytecodealliance/preview2-prototyping#7736fd0c)`
... which satisfies git dependency `host` of package `wasmtime_host_test v0.1.0 (/home/yohann/devs/neo-michel/wasmtime_host_test)`
versions that meet the requirements `=6.0.0` are: 6.0.0
the package `wasmtime-fiber` links to the native library `wasmtime-fiber-shims`, but it conflicts with a previous package which links to `wasmtime-fiber-shims` as well:
package `wasmtime-fiber v6.0.0`
... which satisfies dependency `wasmtime-fiber = "=6.0.0"` of package `wasmtime v6.0.0`
... which satisfies dependency `wasmtime = "^6.0.0"` of package `wasmtime_host_test v0.1.0 (/home/yohann/devs/neo-michel/wasmtime_host_test)`
Only one package in the dependency graph may specify the same links value. This helps ensure that only one copy of a native library is linked in the final binary. Try to adjust your dependencies so that only one package uses the links ='wasmtime-fiber' value. For more information, see https://doc.rust-lang.org/cargo/reference/resolver.html#links.
failed to select a version for `wasmtime-fiber` which could resolve this conflict
thats crgo's way of showing you there are multiple versions of wasmtime pulled in
Pat Hickey (Feb 21 2023 at 17:23):(not ideal)
bjorn3 (Feb 21 2023 at 17:23):You need to use
wasmtime = { git = "https://github.com/bytecodealliance/wasmtime", features = ["component-model"], branch = 'release-6.0.0' }
as that is what preview2-prototyping used too.
bachrc (Feb 21 2023 at 17:24):Yeah, but all I see are version 6.0.0, so there should be no problem haha
bachrc (Feb 21 2023 at 17:24):Thank to both of you, I'm gonna try this :)
Pat Hickey (Feb 21 2023 at 17:24):git versions and crates.io versions are not compatible, even if they say the same string
Pat Hickey (Feb 21 2023 at 17:24):we can update preview2-prototyping to point at the crates.io release, it landed this morning, but all of the people who hack on that are in a meeting today so we havent gotten to it yet
bachrc (Feb 21 2023 at 17:27):Okay, I understand better now :) And this is working like this! Thank you for your kind and quick answers and your hard work :)
Notification Bot (Feb 21 2023 at 17:27):bachrc has marked this topic as resolved.
Notification Bot (Feb 21 2023 at 17:36):bachrc has marked this topic as unresolved.
bachrc (Feb 21 2023 at 17:38):Well, I guess using the add_to_linker is incompatible with the one given by my bindgen! macro? :(
bachrc (Feb 21 2023 at 17:38):let mut linker = Linker::new(&engine);
host::add_to_linker(&mut linker, |x| x)?;
Michel::add_to_linker(&mut linker, |state: &mut MichelApiForPlugins| state)?;
can you share the error message?
bachrc (Feb 21 2023 at 17:41):Here the compiler isn't happy because there is two types or states given to the linker : WasiCtx (by the host), and MichelApiForPlugins (which is my state)
bachrc (Feb 21 2023 at 17:42):error[E0631]: type mismatch in closure arguments
--> wasmtime_host_test/src/main.rs:34:5
|
34 | Michel::add_to_linker(&mut linker, |state: &mut MichelApiForPlugins| state)?;
| ^^^^^^^^^^^^^^^^^^^^^ --------------------------------- found signature defined here
| |
| expected due to this
|
= note: expected closure signature `for<'a> fn(&'a mut WasiCtx) -> _`
found closure signature `for<'a> fn(&'a mut MichelApiForPlugins) -> _`
right, so you want to make some struct Ctx { wasi: WasiCtx, michel: MichaelApiForPlugins }, and in the linker you use |ctx| &mut ctx.wasi for wasi, |ctx| &mut ctx.michel for michel
Pat Hickey (Feb 21 2023 at 17:42):thats how the linker is designed to deal with compositions of state
bachrc (Feb 21 2023 at 17:43):Oh okay I see! I hope my struggles will help people searching here :) Thanks again for your answer!
bachrc (Feb 21 2023 at 18:00):Yup, but making the Linker contain our new Ctx is incompatible with the instantiate_async generated by the bindgen!.
let (bindings,_) = Michel::instantiate_async(&mut store, &component, &linker).await?;
Here it waits for the same generic type for store and linker. Well I guess my Store should not be MichelPluginForApi anymore, but Ctx ? But for creating a Ctx object, I need to create a WasiCtx. You know how I could do this? :(
bachrc (Feb 21 2023 at 18:00):Oh yes, the WasiCtxBuilder !
bachrc (Feb 21 2023 at 18:01):I'm trying this now.
Pat Hickey (Feb 21 2023 at 18:01):yes
Pat Hickey (Feb 21 2023 at 18:01):and your store will need to be a Store<Ctx>
bachrc (Feb 21 2023 at 21:14):Sorry to bother again, but trying to get the WasiCtsBuilder with the wasmtime-wasi dependency :
wasmtime-wasi = { git = "https://github.com/bytecodealliance/wasmtime", branch = 'release-6.0.0' }
But again, a version conflict. I don't see what's wrong here :(
stdout : Updating crates.io index
Updating git repository `https://github.com/bytecodealliance/wasmtime`
error: failed to select a version for `wasi-common`.
... required by package `wasmtime-wasi v6.0.0 (https://github.com/bytecodealliance/wasmtime?branch=release-6.0.0#c00d3f05)`
... which satisfies git dependency `wasmtime-wasi` of package `wasmtime_host_test v0.1.0 (/home/yohann/devs/neo-michel/wasmtime_host_test)`
versions that meet the requirements `=6.0.0` are: 6.0.0
the package `wasi-common` links to the native library `wasi-common-19`, but it conflicts with a previous package which links to `wasi-common-19` as well:
package `wasi-common v0.0.0 (https://github.com/bytecodealliance/preview2-prototyping#7736fd0c)`
... which satisfies git dependency `wasi-common` (locked to 0.0.0) of package `host v0.0.0 (https://github.com/bytecodealliance/preview2-prototyping#7736fd0c)`
... which satisfies git dependency `host` (locked to 0.0.0) of package `wasmtime_host_test v0.1.0 (/home/yohann/devs/neo-michel/wasmtime_host_test)`
Only one package in the dependency graph may specify the same links value. This helps ensure that only one copy of a native library is linked in the final binary. Try to adjust your dependencies so that only one package uses the links ='wasi-common' value. For more information, see https://doc.rust-lang.org/cargo/reference/resolver.html#links.
failed to select a version for `wasi-common` which could resolve this conflict
You can’t use wasi-common from the prototype repo and the one upstream in Wasmtime in the same project right now.
Pat Hickey (Feb 21 2023 at 21:53):We will merge all that functionality back in upstream at some point, but right now they can’t coexist
Pat Hickey (Feb 21 2023 at 21:53):If you delete the links section in the prototype cargo.toml it might work
bachrc (Feb 21 2023 at 22:08):Ah. So I can't use WasiCtxBuilder, and so using wit-bindgen
bachrc (Feb 21 2023 at 22:09):I can't modify the prototype Cargo.toml without doing a fork
bachrc (Feb 21 2023 at 22:14):And i don't see any links section in https://github.com/bytecodealliance/preview2-prototyping/blob/main/Cargo.toml
bachrc (Feb 22 2023 at 00:55):Well I see here (https://bytecodealliance.zulipchat.com/#narrow/stream/327223-wit-bindgen/topic/.5Brust.5D.20wasmtime.20.26.20custom.20wit.20type.20.28record.29) that i should maybe import wasi_cap_sync from the std!
Giom (Feb 22 2023 at 15:58):Hey i managed to get it working by adding the following line to my cargo.toml of the host project:
wasi-cap-std-sync = { git = "https://github.com/bytecodealliance/preview2-prototyping", rev = "7736fd0" }
Then i was able to use the WasiCtxBuilder.
bachrc (Feb 23 2023 at 21:56):Yeah, to make this work, I was forced to clone locally the preview2-prototyping, and remove the [links] section.
Notification Bot (Feb 23 2023 at 21:57):bachrc has marked this topic as resolved.
Elia Bieri (Mar 05 2023 at 12:50):Could you send me the example you used to get it working?
Last updated: Oct 23 2024 at 20:03 UTC