Error sending rpc method invocation response: No caller found

[endrik-exe]

Version: 0.13.3

I have registered this RPC method in node sdk. and then trigger it from livekit-client-js

room.localParticipant.registerRpcMethod('mousemove', async (data: RpcInvocationData) => {
    const { x, y } = JSON.parse(data.payload);

    const width = this.page.viewportSize()?.width ?? 1
    const height = this.page.viewportSize()?.height ?? 1

    this.page.mouse.move(x * width, y * height);

    return '';
});

It did get called several times, but then i get this error in console: error sending rpc method invocation response: No caller found

node-sdks/packages/livekit-rtc/src/participant.ts

Line 536 in 473c46b

console.warn(`error sending rpc method invocation response: ${res.error}`);

After this error message appeared, it seems the node-sdk cannot receive rpc call again.

Do you have any idea?

[lukasIO]

how often are you sending these RPC's ? on every mousemove event of the browser?

[endrik-exe]

how often are you sending these RPC's ? on every mousemove event of the browser?

Yes, on every mousemove event.

when I throttling it to 10 times a second, or 100 ms delay. using this helper: https://vueuse.org/shared/useDebounceFn .
The problem seems go away.

[lukasIO]

RPC calls are not designed for this kind of high frequency event, also you'll get worse throughput because it always comes with additional overhead if you perform RPCs. To send mousemove events the recommended approach would be to use publishData directly on a custom topic.

I'll leave this issue open as there is might still a bug around how callers are handled.
cc @bcherry for additional insight

[bcherry]

yeah RPC isn't really designed for the high volume but the specific issue you have turned out to be a bug on our side anyways livekit/rust-sdks#565

will get fixed here in the next release