Stream: general

Topic: ✔ Cannot build and run wasm32-wasi components

Nick (Sep 01 2023 at 02:55):

While trying to test very simple WASI components, I am getting errors associated with the return type of wasi:io/streams write method.

I think the source of the problem is that the wit files defining wasi:io/streams are different across different versions and don't appear to match for the current head of cargo component (e57d1d1) and wasmtime-wasi (12.0.1).
When I look at the build of my component I see

$ wasm-tools print target/wasm32-wasi/debug/rand.wasm
(component
  (type (;0;)
    (instance
      (type (;0;) u32)
      (export (;1;) "input-stream" (type (eq 0)))
      (type (;2;) u32)
      (export (;3;) "output-stream" (type (eq 2)))
      (type (;4;) (enum "open" "ended"))
      (export (;5;) "stream-status" (type (eq 4)))
      (type (;6;) (func (param "this" 1)))
      (export (;0;) "drop-input-stream" (func (type 6)))
      (type (;7;) (list u8))
      (type (;8;) (tuple u64 5))
      (type (;9;) (result 8))
      (type (;10;) (func (param "this" 3) (param "buf" 7) (result 9)))
      (export (;1;) "write" (func (type 10)))
      (export (;2;) "blocking-write" (func (type 10)))
      (type (;11;) (func (param "this" 3)))
      (export (;3;) "drop-output-stream" (func (type 11)))
    )
  )
...

which indicates a write type of func(this: u32, buf: list<u8>, result<u64, stream-status>).
This matches here and here.

However, the wasmtime-wasi=11.01 and wasmtime-wasi=12.01 both differ from this definition!
According the files downloaded to my .cargo/registry:

wasmtime-wasi 11.01

write: func(
    this: output-stream,
    /// Data to write
    buf: list<u8>
) -> result<u64, stream-error>

wasmtime-wasi 12.01

write: func(
    this: output-stream,
    /// Data to write
    buf: list<u8>
) -> result<tuple<u64, stream-status>, stream-error>

How can I get my wasm32-wasi component building and running?

Alex Crichton (Sep 01 2023 at 03:02):

You'll want to pair the adapter and Wasmtime together at this time. WASI is evolving meaning that if any one piece of the toolchain/tooling/etc uses WASI then everything must agree on that. Can you use the adapter and Wasmtime both at version 12?

Nick (Sep 01 2023 at 03:05):

Gotcha. I'll give it a try and report back, thanks.

Nick (Sep 01 2023 at 03:39):

Yup, that worked; thanks!

Notification Bot (Sep 01 2023 at 03:39):

Nick has marked this topic as resolved.

Last updated: Dec 23 2024 at 13:07 UTC