Stream: wasmtime

Topic: Invalid input WebAssembly

Wim Henderickx (Dec 03 2024 at 14:49):

I am new to this space so bear with me. I am experimenting with WASM/WIT a bit and want to build a host program in go and use wasmtime and components in various languages starting with python.
So i created a WIT.like this.

package example:reconciler@0.1.0;

world reconciler {
import reconcile: func(input: string) -> string;
}

create a python component

import reconciler
import json

class Reconciler(reconciler.reconciler):
def reconcile(self, input_json: str) -> str:
# Parse the input JSON
data = json.loads(input_json)

    # Perform reconciliation logic
    result = {
        "status": "success",
        "processed_items": len(data.get("items", []))
    }

    # Return the result as a JSON string
    return json.dumps(result)

and generated a wasm file using the following command

componentize-py --wit-path wit --world reconciler bindings .
componentize-py --wit-path wit --world reconciler componentize reconciler -o reconciler.wasm

now the part that fails is the go program when i try to run the wasm file i get the error here.

package main

import (
"encoding/json"
"fmt"

"github.com/bytecodealliance/wasmtime-go"

)

func main() {
// Load the WebAssembly module
engine := wasmtime.NewEngine()
store := wasmtime.NewStore(engine)

wasiConfig := wasmtime.NewWasiConfig()
store.SetWasi(wasiConfig)

module, err := wasmtime.NewModuleFromFile(engine, "reconciler.wasm")
if err != nil {
    panic(err)
}

}

error:

(.venv) (base) wasm/reconciler > go run main.go
panic: failed to parse WebAssembly module

Caused by:
Invalid input WebAssembly code at offset 4: unknown binary version

goroutine 1 [running]:
main.main()
/Users/henderiw/code/wasm/reconciler/main.go:20 +0x2b0
exit status 2

when i inspect the reconciler.wasm file i wasm-tools validate seems ok

(.venv) (base) wasm/reconciler > wasm-tools validate reconciler.wasm
(.venv) (base) wasm/reconciler > xxd reconciler.wasm | head -n 1
00000000: 0061 736d 0d00 0100 0756 0142 0a01 6f02 .asm.....V.B..o.
(.venv) (base) wasm/reconciler > wasm-tools component wit reconciler.wasm
package root:component;

world root {
import wasi:cli/environment@0.2.0;
import wasi:cli/exit@0.2.0;
import wasi:io/error@0.2.0;
import wasi:io/poll@0.2.0;
import wasi:io/streams@0.2.0;
import wasi:cli/stdin@0.2.0;
import wasi:cli/stdout@0.2.0;
import wasi:cli/stderr@0.2.0;
import wasi:cli/terminal-input@0.2.0;
import wasi:cli/terminal-output@0.2.0;
import wasi:cli/terminal-stdin@0.2.0;
import wasi:cli/terminal-stdout@0.2.0;
import wasi:cli/terminal-stderr@0.2.0;
import wasi:clocks/monotonic-clock@0.2.0;
import wasi:clocks/wall-clock@0.2.0;
import wasi:filesystem/types@0.2.0;
import wasi:filesystem/preopens@0.2.0;
import wasi:sockets/network@0.2.0;
import wasi:sockets/instance-network@0.2.0;
import wasi:sockets/udp@0.2.0;
import wasi:sockets/udp-create-socket@0.2.0;
import wasi:sockets/tcp@0.2.0;
import wasi:sockets/tcp-create-socket@0.2.0;
import wasi:sockets/ip-name-lookup@0.2.0;
import wasi:random/random@0.2.0;
import wasi:random/insecure@0.2.0;
import wasi:random/insecure-seed@0.2.0;
import reconcile: func(input: string) -> string;

export exports: interface {
record bundled {
module: string,
protocol: string,
name: string,
}

...

Not sure what i am doing wrong here. So looking for advise

Lann Martin (Dec 03 2024 at 15:02):

WebAssembly "modules" are different from "components". componentize-py produces a component but your Go code is attempting to load it as a module (wasmtime.NewModuleFromFile). I am not very familiar with wasmtime-go but I believe it does not yet support loading components.

Wim Henderickx (Dec 03 2024 at 16:02):

ok that would explain. I was trying to find something for components but did not find anything hence i used the Module.

Wim Henderickx (Dec 03 2024 at 16:03):

Is something in the working for components in wasmtime? or should we use another host runtime for this?

Lann Martin (Dec 03 2024 at 16:11):

Wasmtime is currently the best host runtime option for components, its just that the non-Rust language bindings lag behind feature-wise.

Lann Martin (Dec 03 2024 at 16:12):

The only other relevant component implementation I am aware of is jco which adapts components to run in JS environments (e.g. Node, browsers) but it comes with a number of caveats compared to Wasmtime.

Wim Henderickx (Dec 03 2024 at 18:20):

Alright thx for the pointer.

Last updated: Dec 23 2024 at 13:07 UTC