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all goroutines are dead asleep - deadlock! wasm docs

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#426 8 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
30/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
go, wasm
Domain
networking

Research direction

Start with cmd/go-ws-client/main.go and reproduce the window.goWS("ws://localhost:8080/ws-chat") call using the provided index.html and Makefile commands. Then inspect ws_js.go around the reported Dial stack frame and compare the WebAssembly behavior with the server example. Done means the deadlock is explained and the issue's documented usage or reproduction is corrected and verified.

Written by the indexing model from the issue text.

Description

docs

I'm trying to do the next:

Client Code:
//go:build js && wasm

package main

import (
	"context"
	"log"
	"syscall/js"

	"nhooyr.io/websocket"
)

func main() {
	ctx := context.Background()
	window := js.Global()
	window.Set("goWS", js.FuncOf(func(_ js.Value, args []js.Value) any {
		conn, _, err := websocket.Dial(ctx, args[0].String(), nil)
		if err != nil {
			log.Fatal(err)
		}
		goWSObject := window.Get("goWS")
		goWSObject.Set("send", js.FuncOf(func(_ js.Value, args []js.Value) any {
			if err := conn.Write(ctx, websocket.MessageText, []byte(args[0].String())); err != nil {
				log.Fatal(err)
			}
			return nil
		}))
		goWSObject.Set("waitMessage", js.FuncOf(func(_ js.Value, _ []js.Value) any {
			_, bb, err := conn.Read(ctx)
			if err != nil {
				log.Fatal(err)
			}
			return bb
		}))
		return nil
	}))
	waitCh := make(chan struct{})
	<-waitCh
}
index.html:
<!doctype html>
<html lang="en">
<head>
	<meta charset="UTF-8" />
	<meta name="viewport" content="width=device-width, initial-scale=1.0" />
	<title>goWS</title>
	<script src="/assets/wasm_exec.js"></script>
	<script>
		const go = new Go();
		WebAssembly.instantiateStreaming(fetch("/assets/app.wasm"), go.importObject)
			.then(res => go.run(res.instance))
	</script>
</head>
<body>
</body>
</html>
Server code:
package main

import (
	"context"
	"net/http"

	"nhooyr.io/websocket"
)

func main() {
	ctx := context.Background()

	http.HandleFunc("/ws-chat", func(w http.ResponseWriter, r *http.Request) {
		conn, err := websocket.Accept(w, r, &websocket.AcceptOptions{
			InsecureSkipVerify: true,
		})
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		_, bb, err := conn.Read(ctx)
		if err != nil {
			conn.Close(websocket.StatusInternalError, err.Error())
			return
		}
		wr, err := conn.Writer(ctx, websocket.MessageText)
		if err != nil {
			conn.Close(websocket.StatusInternalError, err.Error())
			return
		}
		wr.Write(bb)
		wr.Close()
		conn.CloseNow()
	})
	http.ListenAndServe(":8080", http.DefaultServeMux)
}

Also I'm going to attach my Makefile so you can see the commands when I'm compiling:

build_client:
	GOOS=js GOARCH=wasm go build -o dist/assets/app.wasm cmd/go-ws-client/main.go
	cp $(go env GOROOT)/misc/wasm/wasm_exec.js dist/assets/

build_server:
	go build -o dist/bin/app-server cmd/go-ws-server/main.go
Structure of dist folder:
dist/
	- assets/
		- app.wasm
		- wasm_exec.js
	- bin/
		- app-server
	- index.html

But i'm getting the following errors after calling window.goWS("ws://localhost:8080/ws-chat") from the firefox browser's console:

Console:
> window.goWS("ws://localhost:8080/ws-chat")
fatal error: all goroutines are asleep - deadlock! wasm_exec.js:22:14
<empty string>
wasm_exec.js:22:14
goroutine 1 [chan receive]: wasm_exec.js:22:14
main.main() wasm_exec.js:22:14
	/home/oscar/Escritorio/proyecto-react/cmd/go-ws-client/main.go:47 +0xc wasm_exec.js:22:14
<empty string> wasm_exec.js:22:14
goroutine 7 [select]: wasm_exec.js:22:14
nhooyr.io/websocket.dial({0x5aa80, 0x1430050}, {0x1466020, 0x1b}, 0x0) wasm_exec.js:22:14
	/home/oscar/go/pkg/mod/nhooyr.io/websocket@v1.8.10/ws_js.go:320 +0x1c wasm_exec.js:22:14
nhooyr.io/websocket.Dial({0x5aa80, 0x1430050}, {0x1466020, 0x1b}, 0x0) wasm_exec.js:22:14
	/home/oscar/go/pkg/mod/nhooyr.io/websocket@v1.8.10/ws_js.go:289 +0x2 wasm_exec.js:22:14
main.main.func1.1({{}, 0x0, 0x0}, {0x140e0f0, 0x1, 0x1}) wasm_exec.js:22:14
	/home/oscar/Escritorio/proyecto-react/cmd/go-ws-client/main.go:19 +0x4 wasm_exec.js:22:14
syscall/js.handleEvent() wasm_exec.js:22:14
	/usr/local/go/src/syscall/js/func.go:100 +0x26 wasm_exec.js:22:14
exit code: 2 wasm_exec.js:101:14
undefined
Dominant language
Go
Stars
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Forks
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PR merge metrics
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