Change panic handler to log the WASM stacktrace (#31)

edmocosta · web-flow · commit 963b42aefcf8 · 2026-01-15T10:31:05.000+01:00
diff --git a/wasm/main.go b/wasm/main.go
@@ -23,6 +23,7 @@ package main
 
 import (
 	"fmt"
+	"runtime/debug"
 	"syscall/js"
 
 	"github.com/elastic/ottl-playground/wasm/internal"
@@ -34,7 +35,7 @@ func handlePanic() {
 	}()
 	if r := recover(); r != nil {
 		js.Global().Call("wasmPanicHandler", fmt.Sprintf("An error occurred in the WASM module: %v", r))
-		js.Global().Get("console").Call("error", "stack trace:", js.Global().Get("Error").New().Get("stack").String())
+		js.Global().Get("console").Call("error", fmt.Sprintf("[WASM] %v %s", r, string(debug.Stack())))
 	}
 }
 

Original file line number	Diff line number	Diff line change
`@@ -23,6 +23,7 @@ package main`
`23`	`23`
`24`	`24`	`import (`
`25`	`25`	`"fmt"`
	`26`	`+ "runtime/debug"`
`26`	`27`	`"syscall/js"`
`27`	`28`
`28`	`29`	`"github.com/elastic/ottl-playground/wasm/internal"`
`@@ -34,7 +35,7 @@ func handlePanic() {`
`34`	`35`	`}()`
`35`	`36`	`if r := recover(); r != nil {`
`36`	`37`	`js.Global().Call("wasmPanicHandler", fmt.Sprintf("An error occurred in the WASM module: %v", r))`
`37`		`- js.Global().Get("console").Call("error", "stack trace:", js.Global().Get("Error").New().Get("stack").String())`
	`38`	`+ js.Global().Get("console").Call("error", fmt.Sprintf("[WASM] %v %s", r, string(debug.Stack())))`
`38`	`39`	`}`
`39`	`40`	`}`
`40`	`41`