Cloudflare Websocket with Durable Objects not working

[LawrenceGB]

Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/cloudflare

SDK Version

9.11.0

Framework Version

No response

Link to Sentry event

No response

Reproduction Example/SDK Setup

import { DurableObject } from "cloudflare:workers";
import * as Sentry from '@sentry/cloudflare';

// Worker with Sentry wrapper
export default Sentry.withSentry(
	env => ({
		dsn: env.SENTRY_DSN,

	}),
	{
		async fetch(request, env, ctx) {
			// Handle WebSocket requests
			if (request.url.includes("/websocket")) {
				// Get DO stub
				const id = env.WEBSOCKET_SERVER.idFromName("user-id");
				const stub = env.WEBSOCKET_SERVER.get(id);

				// Forward to DO
				return await stub.fetch(request);
			}

			return new Response("Not a WebSocket request");
		},
	}
);

// Durable Object for WebSocket
export class WebSocketServer extends DurableObject {
	constructor(ctx, env) {
		super(ctx, env);
	}

	async fetch(request) {
		// Verify WebSocket upgrade
		const upgradeHeader = request.headers.get("Upgrade");
		if (!upgradeHeader || upgradeHeader.toLowerCase() !== "websocket") {
			return new Response("Expected WebSocket", { status: 426 });
		}

		// Create WebSocket pair
		const webSocketPair = new WebSocketPair();
		const [client, server] = Object.values(webSocketPair);

		// Accept the server side
		server.accept();

		// Basic message handler
		server.addEventListener("message", (event) => {
			server.send("Echo: " + event.data);
		});

		Sentry.captureException(new Error('Testing sentry'));


		// Return client WebSocket
		return new Response(null, {
			status: 101,
			webSocket: client
		});
	}
}

Steps to Reproduce

Just added a test exception, did not show up.

Expected Result

Should have received the error in dashboard.

Actual Result

Did not show.
However, it does work when running the worker locally.

[Lms24]

Hey @LawrenceGB I believe your issue is a duplicate to #15342. I'm not fully involved in our CloudFlare SDK (therefore tagging @AbhiPrasad) but as far as I can tell, the SDK is not initialized in your WebSocketServer instance.
In the issue, someone posted a workaround for durable objects. Would you mind giving this a try?

[AbhiPrasad]

Yup, we don't wrap DurableObjects yet, we can backlog this as a feature, but the workaround should work as expected.

[LawrenceGB]

@Lms24 @AbhiPrasad
The workaround solved it, thanks!

[AbhiPrasad]

re-opening this so we can track wrapping the durable objects built-in by default

[dcramer]

https://github.com/cloudflare/agents/blob/3824fd4dfdd99c80cba5ea031e950a460d495256/packages/agents/src/mcp/index.ts#L319