【次世代高速RDB劔"Tsurugi"】Tsurugi UDTF で Web ブラウザから仮想端末を操作する

SELECT u.output_data
FROM (VALUES (
  CAST(:op AS VARCHAR(32)),
  CAST(:session_id AS VARCHAR(500)),
  CAST(:payload AS VARBINARY(262144)),
  CAST(:max_bytes AS INT)))
  AS p(op, session_id, payload, max_bytes)
CROSS APPLY Relay(p.op, p.session_id, p.payload, p.max_bytes) AS u(output_data)

syntax = "proto3";

option java_multiple_files = true;
option java_package = "com.nautilus_technologies.tsurugi_tty.udtf";
option java_outer_classname = "TerminalRelayUdtfProto";

service TerminalRelayUdtf {
  rpc Relay(RelayRequest) returns (stream RelayRow);
}

message RelayRequest {
  string op = 1;
  string session_id = 2;
  bytes payload = 3;
  uint32 max_bytes = 4;
}

message RelayRow {
  bytes output_data = 1;
}

@Override
public void relay(RelayRequest request, StreamObserver<RelayRow> responseObserver) {
    String op = request.getOp().toUpperCase(Locale.ROOT);
    String sid = request.getSessionId();
    try {
        switch (op) {
            case "HEARTBEAT" -> {
                PtySession s = sessions.getOrCreate(sid);
                s.touch();
            }
            case "SEND_INPUT" -> {
                PtySession s = sessions.getOrCreate(sid);
                s.writeInput(request.getPayload().toByteArray());
            }
            case "POLL_OUTPUT" -> {
                byte[] out = sessions.pollOutput(sid, request.getMaxBytes());
                if (out.length > 0) {
                    responseObserver.onNext(
                            RelayRow.newBuilder().setOutputData(ByteString.copyFrom(out)).build());
                }
            }
            default -> {
                responseObserver.onError(
                        Status.INVALID_ARGUMENT
                                .withDescription("unknown op: " + request.getOp())
                                .asRuntimeException());
                return;
            }
        }
        responseObserver.onCompleted();
    } catch (IOException e) {
        responseObserver.onError(
                Status.INTERNAL
                        .withDescription("relay io error: " + e.getMessage())
                        .withCause(e)
                        .asRuntimeException());
    }
}