FastDDS 发布者和订阅者在演示代码中不匹配

问题描述 投票：0回答：1

我正在尝试在此处设置 FastDDS 教程中的 Hello World 示例：https://fast-dds.docs.eprosima.com/en/latest/fastdds/getting_started/simple_app/simple_app.html

当我运行发布者和订阅者（单独的终端）时，他们无法找到对方。我从来没有得到“发布者匹配”和“订阅者匹配”行。

我可以在这里寻找什么？有没有办法查看所有正在发布/订阅的主题？是否需要进行一些配置才能在本地主机上运行它们？

我能想到的就是仔细检查主题名称，并添加一个 

cout
行来打印（如果发布者不匹配）。除了添加打印语句之外，我没有更改教程页面中的代码，所以我不确定如何继续。

在发布者代码中：

/**
 * @file HelloWorldPublisher.cpp
 *
 */

#include "HelloWorldPubSubTypes.h"

#include <chrono>
#include <thread>

#include <fastdds/dds/domain/DomainParticipant.hpp>
#include <fastdds/dds/domain/DomainParticipantFactory.hpp>
#include <fastdds/dds/publisher/DataWriter.hpp>
#include <fastdds/dds/publisher/DataWriterListener.hpp>
#include <fastdds/dds/publisher/Publisher.hpp>
#include <fastdds/dds/topic/TypeSupport.hpp>

using namespace eprosima::fastdds::dds;

class HelloWorldPublisher
{
private:

    HelloWorld hello_;

    DomainParticipant* participant_;

    Publisher* publisher_;

    Topic* topic_;

    DataWriter* writer_;

    TypeSupport type_;

    class PubListener : public DataWriterListener
    {
    public:

        PubListener()
            : matched_(0)
        {
        }

        ~PubListener() override
        {
        }

        void on_publication_matched(
                DataWriter*,
                const PublicationMatchedStatus& info) override
        {
            if (info.current_count_change == 1)
            {
                matched_ = info.total_count;
                std::cout << "Publisher matched." << std::endl;
            }
            else if (info.current_count_change == -1)
            {
                matched_ = info.total_count;
                std::cout << "Publisher unmatched." << std::endl;
            }
            else
            {
                std::cout << info.current_count_change
                        << " is not a valid value for PublicationMatchedStatus current count change." << std::endl;
            }
        }

        std::atomic_int matched_;

    } listener_;

public:

    HelloWorldPublisher()
        : participant_(nullptr)
        , publisher_(nullptr)
        , topic_(nullptr)
        , writer_(nullptr)
        , type_(new HelloWorldPubSubType())
    {
    }

    virtual ~HelloWorldPublisher()
    {
        if (writer_ != nullptr)
        {
            publisher_->delete_datawriter(writer_);
        }
        if (publisher_ != nullptr)
        {
            participant_->delete_publisher(publisher_);
        }
        if (topic_ != nullptr)
        {
            participant_->delete_topic(topic_);
        }
        DomainParticipantFactory::get_instance()->delete_participant(participant_);
    }

    //!Initialize the publisher
    bool init()
    {
        hello_.index(0);
        hello_.message("HelloWorld");

        DomainParticipantQos participantQos;
        participantQos.name("Participant_publisher");
        participant_ = DomainParticipantFactory::get_instance()->create_participant(0, participantQos);

        if (participant_ == nullptr)
        {
            return false;
        }

        // Register the Type
        type_.register_type(participant_);

        // Create the publications Topic
        topic_ = participant_->create_topic("HelloWorldTopic", "HelloWorld", TOPIC_QOS_DEFAULT);

        if (topic_ == nullptr)
        {
            return false;
        }

        // Create the Publisher
        publisher_ = participant_->create_publisher(PUBLISHER_QOS_DEFAULT, nullptr);

        if (publisher_ == nullptr)
        {
            return false;
        }

        // Create the DataWriter
        writer_ = publisher_->create_datawriter(topic_, DATAWRITER_QOS_DEFAULT, &listener_);

        if (writer_ == nullptr)
        {
            return false;
        }
        return true;
    }

    //!Send a publication
    bool publish()
    {
        if (listener_.matched_ > 0)
        {
            hello_.index(hello_.index() + 1);
            writer_->write(&hello_);
            return true;
        }
        return false;
    }

    //!Run the Publisher
    void run(
            uint32_t samples)
    {
        uint32_t samples_sent = 0;
        while (samples_sent < samples)
        {
            if (publish())
            {
                samples_sent++;
                std::cout << "Message: " << hello_.message() << " with index: " << hello_.index()
                            << " SENT" << std::endl;
            }
            std::this_thread::sleep_for(std::chrono::milliseconds(1000));
        }
    }
};

int main(
        int argc,
        char** argv)
{
    std::cout << "Starting publisher." << std::endl;
    uint32_t samples = 10;

    HelloWorldPublisher* mypub = new HelloWorldPublisher();
    if(mypub->init())
    {
        mypub->run(samples);
    }

    delete mypub;
    return 0;
}

这是订阅者代码：

#include "HelloWorldPubSubTypes.h"

#include <chrono>
#include <thread>

#include <fastdds/dds/domain/DomainParticipant.hpp>
#include <fastdds/dds/domain/DomainParticipantFactory.hpp>
#include <fastdds/dds/subscriber/DataReader.hpp>
#include <fastdds/dds/subscriber/DataReaderListener.hpp>
#include <fastdds/dds/subscriber/qos/DataReaderQos.hpp>
#include <fastdds/dds/subscriber/SampleInfo.hpp>
#include <fastdds/dds/subscriber/Subscriber.hpp>
#include <fastdds/dds/topic/TypeSupport.hpp>

using namespace eprosima::fastdds::dds;

class HelloWorldSubscriber
{
private:

    DomainParticipant* participant_;

    Subscriber* subscriber_;

    DataReader* reader_;

    Topic* topic_;

    TypeSupport type_;

    class SubListener : public DataReaderListener
    {
    public:

        SubListener()
            : samples_(0)
        {
        }

        ~SubListener() override
        {
        }

        void on_subscription_matched(
                DataReader*,
                const SubscriptionMatchedStatus& info) override
        {
            if (info.current_count_change == 1)
            {
                std::cout << "Subscriber matched." << std::endl;
            }
            else if (info.current_count_change == -1)
            {
                std::cout << "Subscriber unmatched." << std::endl;
            }
            else
            {
                std::cout << info.current_count_change
                        << " is not a valid value for SubscriptionMatchedStatus current count change" << std::endl;
            }
        }

        void on_data_available(
                DataReader* reader) override
        {
            SampleInfo info;
            if (reader->take_next_sample(&hello_, &info) == ReturnCode_t::RETCODE_OK)
            {
                if (info.valid_data)
                {
                    samples_++;
                    std::cout << "Message: " << hello_.message() << " with index: " << hello_.index()
                                << " RECEIVED." << std::endl;
                }
            }
            else {
              std::cout<<"\n Error reading\n";
            }
        }

        HelloWorld hello_;

        std::atomic_int samples_;

    } listener_;

public:

    HelloWorldSubscriber()
        : participant_(nullptr)
        , subscriber_(nullptr)
        , topic_(nullptr)
        , reader_(nullptr)
        , type_(new HelloWorldPubSubType())
    {
    }

    virtual ~HelloWorldSubscriber()
    {
        if (reader_ != nullptr)
        {
            subscriber_->delete_datareader(reader_);
        }
        if (topic_ != nullptr)
        {
            participant_->delete_topic(topic_);
        }
        if (subscriber_ != nullptr)
        {
            participant_->delete_subscriber(subscriber_);
        }
        DomainParticipantFactory::get_instance()->delete_participant(participant_);
    }

    //!Initialize the subscriber
    bool init()
    {
        DomainParticipantQos participantQos;
        participantQos.name("Participant_subscriber");
        participant_ = DomainParticipantFactory::get_instance()->create_participant(0, participantQos);

        if (participant_ == nullptr)
        {
            return false;
        }

        // Register the Type
        type_.register_type(participant_);

        // Create the subscriptions Topic
        topic_ = participant_->create_topic("HelloWorldTopic", "HelloWorld", TOPIC_QOS_DEFAULT);

        if (topic_ == nullptr)
        {
            return false;
        }

        // Create the Subscriber
        subscriber_ = participant_->create_subscriber(SUBSCRIBER_QOS_DEFAULT, nullptr);

        if (subscriber_ == nullptr)
        {
            return false;
        }

        // Create the DataReader
        reader_ = subscriber_->create_datareader(topic_, DATAREADER_QOS_DEFAULT, &listener_);

        if (reader_ == nullptr)
        {
            return false;
        }

        return true;
    }

    //!Run the Subscriber
    void run(
        uint32_t samples)
    {
        while(listener_.samples_ < samples)
        {
            std::this_thread::sleep_for(std::chrono::milliseconds(100));
        }
    }
};

int main(
        int argc,
        char** argv)
{
    std::cout << "Starting subscriber." << std::endl;
    uint32_t samples = 10;

    HelloWorldSubscriber* mysub = new HelloWorldSubscriber();
    if(mysub->init())
    {
        mysub->run(samples);
    }

    delete mysub;
    return 0;
}

编辑：此代码适用于与我第一次尝试的设备不同的设备。我在同一个网络上运行它 - 使用一台笔记本电脑工作正常，使用另一台笔记本电脑时发布者和订阅者永远不会匹配。

c++ networking publish-subscribe data-distribution-service
1个回答
0
投票

这是因为我设置了环境变量

ROS_DISCOVERY_SERVER
。当我取消设置时，代码按预期工作。

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