Use the websocket-API to get notified when the workflow is complete

[TimPietrusky]

ComfyUI provides a WebSocket-API that can be used to get notified when the workflow is completed. We should use that instead of polling, because it might be way faster.

[Gursehaj]

Maybe you can take some inspiration from this
runpod-serverless-comfyui-worker

[BenDes21]

ComfyUI provides a WebSocket-API that can be used to get notified when the workflow is completed. We should use that instead of polling, because it might be way faster.

Hi , any news ?

[Gursehaj]

You can use runpod sdk to get stream data from the serverless. But for this to work you will have to implement websockets on the handler side yourself. Basically create a generator function.

[TimPietruskyRunPod]

The worker already uses ComfyUI's websocket internally — `handler.py` opens `ws://127.0.0.1:8188/ws?clientId=...` and listens for the `executing` message with `node=None` to detect job completion (see `handler.py:670-720`). That's how we know when to fetch the history and return the result.

What's exposed externally to the client is Runpod's standard serverless API: `/run` (async, poll `/status/{job_id}`), `/runsync` (wait for completion), and `/health`. There's no separate websocket endpoint to subscribe to — that's a Runpod platform feature, not something the worker provides on its own.

PR #221 (currently open) forwards per-step progress through `runpod.serverless.progress_update`, which is the supported way to push intermediate updates that show up in `/status` responses. That's the closest thing to "websocket-style notifications" we have.

Closing — the underlying websocket usage is done, and #221 gives clients per-step visibility. Reopen if you want something specific the existing surface doesn't cover.