[Feature] onError in Streaming Mode Does Not Support Returning Custom Exceptions

[nikbobo]

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Apache Dubbo Component

Java SDK (apache/dubbo)

Descriptions

It is expected that the onError method of StreamObserver can pass through custom exceptions to the Consumer. Currently, the onError method in ServerCallToObserverAdapter is as follows:

public void onError(Throwable throwable) {
    final TriRpcStatus status = TriRpcStatus.getStatus(throwable);
    onCompleted(status);
}

This ultimately returns a StatusRpcException.

Related issues

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[AlbumenJ]

@EarthChen PTAL

[EarthChen]

Yeah, we haven't figured out how to support it yet

[elysium-w]

@nikbobo I have great interest about this issue, could you assign it to me?

[nikbobo]

@nikbobo I have great interest about this issue, could you assign it to me?

I cannot assign to anyone, please contact project admin.

[oxsean]

@elysium-w Sure, but please write a brief proposal before coding.

[oxsean]

I think this requirement is unreasonable. Dubbo's stream is align to gRPC. In gRPC, if StreamObserver.onError is called within a stream, the error information is written back to the client via trailers, and the Throwable is not passed. then the stream is closed. A point we can optimization is provide extension that allow users to write additional error information back to the client.