unknown import: wasi::thread-spawn has not been defined

[owenthereal]

I'm trying to run a wasi program with threads enabled, but I'm getting the following when running it with wasmtime-go:

package main

import (
	"fmt"
	"log"
	"os"
	"path/filepath"

	"github.com/bytecodealliance/wasmtime-go"
)

func main() {
	dir, err := os.MkdirTemp("", "out")
	if err != nil {
		log.Fatal(err)
	}
	defer os.RemoveAll(dir)
	stdoutPath := filepath.Join(dir, "stdout")

	f, err := os.ReadFile(os.Args[1])
	if err != nil {
		log.Fatal(err)
	}

	cfg := wasmtime.NewConfig()
	cfg.SetWasmThreads(true)

	engine := wasmtime.NewEngineWithConfig(cfg)

	module, err := wasmtime.NewModule(engine, f)
	if err != nil {
		log.Fatal(err)
	}

	linker := wasmtime.NewLinker(engine)
	err = linker.DefineWasi()
	if err != nil {
		log.Fatal(err)
	}

	wasiConfig := wasmtime.NewWasiConfig()
	wasiConfig.SetStdoutFile(stdoutPath)

	store := wasmtime.NewStore(engine)
	store.SetWasi(wasiConfig)
	instance, err := linker.Instantiate(store, module)
	if err != nil {
		log.Fatal(err)
	}

	nom := instance.GetFunc(store, "_start")
	_, err = nom.Call(store)
	if err != nil {
		log.Fatal(err)
	}

	// Print WASM stdout
	out, err := os.ReadFile(stdoutPath)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Print(string(out))
}

I was able to run it with wasmtime though: wasmtime --wasm threads --wasi threads program.wasm

[alexcrichton]

Thanks for the report! This is expected though in that this import is part of the wasi-threads proposal which has not been implemented in the C API (nor standardized to a large degree)