errror about operator node in C++

[Jia-Baos]

dataflow.yml file:

nodes:
    - id: node-cpp-api
      path: install/bin/node_cpp_api
      inputs:
          tick: dora/timer/millis/300
      outputs:
          - image

    - id: runtime-node-1
      operators:
          - id: operator-plot
            shared-library: install/lib/operator_plot
            inputs:
                image: node-cpp-api/image

commands to start dataflow.yml

source .venv/bin/activate
dora build dataflow.yml --uv
dora run dataflow.yml --uv

[ERROR]
Dataflow failed:

Node runtime-node-1 failed: exited with code 2 with stderr output:

/home/seer/.local/share/uv/python/cpython-3.11.11-linux-x86_64-gnu/bin/python3.11: can't open file '/home/seer/Project-Rust/dora/examples/cmake-dataflow-camera/runtime': [Errno 2] No such file or directory

[starlitxiling]

Could you create an example so I can reproduce it? Thanks for your work

[vedantvijay]

@dora-bot assign me

[github-actions]

Hello @vedantvijay, this issue is now assigned to you!

[Jia-Baos]

here is the code about operator-plot, its function is to display the image sent by node-cpp-api. In addition, I can use node just fine, but the operator will report an error

operator.h

#pragma once
#include <memory>
#include "operator/operator_api.h"

class Operator
{
public:
    Operator();
    unsigned char counter;
};

#include "dora-operator-api.h"

std::unique_ptr<Operator> new_operator();

DoraOnInputResult on_input(Operator &op, rust::Str id, rust::Slice<const uint8_t> data, OutputSender &output_sender);

operator.cpp

#include "operator.h"
#include <iostream>
#include <vector>
#include "dora-operator-api.h"

#include <opencv2/opencv.hpp>

Operator::Operator() {}

std::unique_ptr<Operator> new_operator()
{
    return std::make_unique<Operator>();
}

DoraOnInputResult on_input(Operator &op, rust::Str id, rust::Slice<const uint8_t> data, OutputSender &output_sender)
{
    op.counter += 1;
    std::cout << "Rust API operator received input `" << id.data() << "` with data `" << (unsigned int)data[0] << "` (internal counter: " << (unsigned int)op.counter << ")" << std::endl;

    // 解码图像数据
    std::vector<unsigned char> img_vec(data.begin(), data.end());
    cv::Mat img = cv::imdecode(img_vec, cv::IMREAD_COLOR);
    if (img.empty())
    {
        std::cout << "Failed to decode image" << std::endl;
        DoraOnInputResult result = {rust::cxxbridge1::String("failed decode image"), false};
        return result;
    }
    else
    {
        cv::namedWindow("frame", cv::WINDOW_NORMAL);
        cv::imshow("frame", img);
        if (int key = cv::waitKey(10) && key == 27)
        {
            DoraOnInputResult result = {rust::cxxbridge1::String("failed decode image"), true};
            return result;
        }
    }

    std::vector<unsigned char> out_vec{op.counter};
    rust::Slice<const uint8_t> out_slice{out_vec.data(), out_vec.size()};
    auto send_result = send_output(output_sender, rust::Str("status"), out_slice);
    DoraOnInputResult result = {send_result.error, false};
    return result;
}

node-plot.cpp

#include "dora-node-api.h"

#include <iostream>
#include <ratio>
#include <string>
#include <vector>

#include <opencv2/opencv.hpp>

int main()
{
    std::cout << "HELLO FROM plot image node" << std::endl;
    unsigned char counter = 0;

    auto dora_node = init_dora_node();

    while (true)
    {
        auto event = next_event(dora_node.events);
        auto ty = event_type(event);

        if (ty == DoraEventType::AllInputsClosed)
        {
            break;
        }
        else if (ty == DoraEventType::Input)
        {
            auto input = event_as_input(std::move(event));

            counter += 1;

            std::cout << "Received input " << std::string(input.id) << " (counter: " << (unsigned int)counter << ")" << std::endl;

            std::cout << "Rust API operator received input, id: " << std::string(input.id) <<  std::endl;

            // 解码图像数据
            std::vector<unsigned char> img_vec(input.data.begin(), input.data.end());
            cv::Mat img = cv::imdecode(img_vec, cv::IMREAD_COLOR);
            if (img.empty())
            {
                std::cout << "Failed to decode image" << std::endl;
            }
            else
            {
                cv::namedWindow("frame", cv::WINDOW_NORMAL);
                cv::imshow("frame", img);
                if (int key = cv::waitKey(10) && key == 27)
                {
                    return 0;
                }
            }
        }
        else
        {
            std::cerr << "Unknown event type " << static_cast<int>(ty) << std::endl;
        }
    }

    std::cout << "GOODBYE FROM plot image node (using Rust API)" << std::endl;

    return 0;
}

[phil-opp]

Thanks for reporting this! Could you try whether it works without the --uv flag?

My suspicion is that this error is caused by #765, especially these lines:

dora/binaries/daemon/src/spawn.rs

Lines 172 to 179 in 79f7304

	if uv {
	let mut cmd = tokio::process::Command::new("uv");
	cmd.arg("run");
	cmd.arg(&resolved_path);
	cmd
	} else {
	tokio::process::Command::new(&resolved_path)
	}

The error message above seems to indicate that the daemon tries to start the dora runtime through uv runtime.

To solve this, we should only use uv if resolved_path points to a python executable. A PR for this would be appreciated!

[Jia-Baos]

emm, it can't works without the --uv flag, and i meet the following error message when start node without the --uv flag

INFO  dataflow `0195f55f-f836-7a66-9fa6-6c4071bd2150` on daemon `d82182f1-3258-4686-a5d6-ca9a1c8d128f` node-cpp-api stdout: HELLO FROM C++
INFO  dataflow `0195f55f-f836-7a66-9fa6-6c4071bd2150` on daemon `d82182f1-3258-4686-a5d6-ca9a1c8d128f` node-cpp-api daemon: node is ready
INFO  dataflow `0195f55f-f836-7a66-9fa6-6c4071bd2150` on daemon `d82182f1-3258-4686-a5d6-ca9a1c8d128f` daemon: all nodes are ready, starting dataflow
INFO  dataflow `0195f55f-f836-7a66-9fa6-6c4071bd2150` on daemon `d82182f1-3258-4686-a5d6-ca9a1c8d128f` node-cpp-api stdout: terminate called after throwing an instance of 'rust::cxxbridge1::Error'
INFO  dataflow `0195f55f-f836-7a66-9fa6-6c4071bd2150` on daemon `d82182f1-3258-4686-a5d6-ca9a1c8d128f` node-cpp-api stdout:   what():  failed to init event stream
INFO  dataflow `0195f55f-f836-7a66-9fa6-6c4071bd2150` on daemon `d82182f1-3258-4686-a5d6-ca9a1c8d128f` node-cpp-api stdout: 
INFO  dataflow `0195f55f-f836-7a66-9fa6-6c4071bd2150` on daemon `d82182f1-3258-4686-a5d6-ca9a1c8d128f` node-cpp-api stdout: 
INFO  dataflow `0195f55f-f836-7a66-9fa6-6c4071bd2150` on daemon `d82182f1-3258-4686-a5d6-ca9a1c8d128f` node-cpp-api daemon: marking `node-cpp-api` as cascading error caused by `runtime-node-1`
ERROR dataflow `0195f55f-f836-7a66-9fa6-6c4071bd2150` on daemon `d82182f1-3258-4686-a5d6-ca9a1c8d128f` node-cpp-api daemon: exited because of signal SIGABRT. This error occurred because node `runtime-node-1` exited before connecting to dora.
INFO  dataflow `0195f55f-f836-7a66-9fa6-6c4071bd2150` on daemon `d82182f1-3258-4686-a5d6-ca9a1c8d128f` daemon: dataflow finished on machine `d82182f1-3258-4686-a5d6-ca9a1c8d128f`
INFO  dataflow `0195f55f-f836-7a66-9fa6-6c4071bd2150` on default daemon coordinator: dataflow finished


[ERROR]
Dataflow 0195f55f-f836-7a66-9fa6-6c4071bd2150 failed:

Node `runtime-node-1` failed: unknown exit status with stderr output:
---------------------------------------------------------------------------------
spawn failed: failed to spawn node `runtime-node-1`

Caused by:
   0: failed to run runtime 0195f55f-f836-7a66-9fa6-6c4071bd2150/runtime-node-1
   1: No such file or directory (os error 2)

Location:
    /home/runner/work/dora/dora/binaries/daemon/src/spawn.rs:339:18
---------------------------------------------------------------------------------



Location:
    binaries/cli/src/lib.rs:693:17

[Arlott8]

@Jia-Baos i tried reporducing the issue but there were some problems. Can you like share git repo or something?

[Jia-Baos]

@Jia-Baos i tried reporducing the issue but there were some problems. Can you like share git repo or something?

Yes, you can refer this:

https://github.com/Jia-Baos/dora/tree/master/examples/cmake-dataflow-camera

I suspect there is a problem with c++ operator because I encountered a similar phenomenon when I start the cmake-example.

[phil-opp]

Thanks for trying!

Your example doesn't seem to different from the cmake-dataflow example in the main dora repo. Does this example work for you? Could you also try to run cargo run --example cmake-dataflow in the dora main repo?