alibaba/nacos · error · NacosException

{}

{}

Error message

{}

What it means

Thrown by GrpcConnection.RequestFuture.get() when the gRPC server returns an ErrorResponse payload instead of a normal Response. The error code and message are taken verbatim from the server-side response (response.getErrorCode(), response.getMessage()), so the '{}' placeholders are filled at runtime. This is the synchronous (non-timed) path of a client-side gRPC request: the call completed on the wire, but the server deliberately reported a logical failure.

Source

Thrown at common/src/main/java/com/alibaba/nacos/common/remote/client/grpc/GrpcConnection.java:104

    
    @Override
    public RequestFuture requestFuture(Request request) throws NacosException {
        Payload grpcRequest = GrpcUtils.convert(request);
        
        final ListenableFuture<Payload> requestFuture = grpcFutureServiceStub.request(grpcRequest);
        return new RequestFuture() {
            
            @Override
            public boolean isDone() {
                return requestFuture.isDone();
            }
            
            @Override
            public Response get() throws Exception {
                Payload grpcResponse = requestFuture.get();
                Response response = (Response) GrpcUtils.parse(grpcResponse);
                if (response instanceof ErrorResponse) {
                    throw new NacosException(response.getErrorCode(), response.getMessage());
                }
                return response;
            }
            
            @Override
            public Response get(long timeout) throws Exception {
                Payload grpcResponse = requestFuture.get(timeout, TimeUnit.MILLISECONDS);
                Response response = (Response) GrpcUtils.parse(grpcResponse);
                if (response instanceof ErrorResponse) {
                    throw new NacosException(response.getErrorCode(), response.getMessage());
                }
                return response;
            }
        };
    }
    
    public void sendResponse(Response response) {
        Payload convert = GrpcUtils.convert(response);

View on GitHub (pinned to 9b989acdf1)

Solutions

1. Inspect NacosException.getErrCode() and getMessage() in the catch block — the real cause is server-supplied, not the placeholder '{}' literal.
2. Verify client and server run compatible Nacos versions (same major, ideally same minor); a version skew is the most common source of unexpected ErrorResponse values.
3. Check server logs for the matching request handling error to identify whether it is auth, validation, or capacity.
4. If the request targets a specific namespace/group/dataId, confirm the resource exists and the credentials used have the required permission.

Example fix

// before
RequestFuture future = connection.request(request);
Response resp = future.get(); // raw, uncaught NacosException

// after
RequestFuture future = connection.request(request);
try {
    Response resp = future.get();
} catch (NacosException e) {
    log.warn("gRPC request failed errCode={} msg={}", e.getErrCode(), e.getErrorMsg());
    // route to caller as a typed domain error
    throw e;
}

RequestFuture future = connection.request(request);
try {
    Response resp = future.get();
} catch (NacosException e) {
    // errCode + message come from the server ErrorResponse
    log.warn("request rejected by server: code={}, msg={}", e.getErrCode(), e.getErrorMsg());
    throw e;
}

When it happens

Trigger: Calling connection.request(req).get() (the no-arg blocking get) on a GrpcConnection where the server responds with a payload whose deserialized type extends ErrorResponse. This happens for any server-rejected request: unsupported server capability, invalid parameters caught server-side, resource-not-found, over-capacity, or auth denial surfaced as an ErrorResponse.

Common situations: Client/server Nacos version mismatch where the server no longer understands a request type; sending a request to a namespace or resource the caller lacks permission for; server-side validation rejecting malformed request fields; server overloaded returning a pushed-back ErrorResponse.

Related errors

• request timeout after {timeout} milliseconds, requestId={req
• {e.getErrCode()}
• 500
• 10000
• PARAMETER_MISSING

AI-assisted analysis of alibaba/nacos@9b989acdf1 (2026-08-14). Data as JSON: /api/errors/39767b009a4f3898. Report an issue: GitHub.