Issues with the use of multiple plugins for publishing and subscribing

[HBing110]

I want to achieve nested message sending for three plugins through a publish-subscribe mechanism.

I have three plugins: BlogManager, BlogEventHandler and BlogManager1:

1. BlogManager first send a topic of event to BlogEventHandler by eventAdmin->publishSignal ;

2. BlogEventHandler receive the topic of event by eventAdmin->subscribeSlot , and send a topic of event to BlogManager1 by eventAdmin->publishSignal

3. BlogManager1 receive the topic of event by eventAdmin->subscribeSlot

---

When sending a message from the second step to the third step, a timeout error is returned.
print result and error ['due to timeout']:

---

BlogEventHandlerActivator::start
BlogEventHandlerActivator::start
BlogEventHandlerActivator::start
BlogManagerActivator::start
BlogManagerActivator::start
BlogEventHandler start ...
BlogManager start ...
BlogManager1 start ...
·***************
BlackList Value Is Empty!!!
BlogManager::publishBlog
start run: 0x526c
QFuture run: 0x4984
BlogEventHandler::handleEvent 1
EventHandler received : title: "CTK Event Admin7771" 0x2624
run over!
10 10 18:10:33 2023 Warning: Blacklisting ServiceReference [1 | Plugin(org.commontk.eventadmin)] due to timeout!
in ctkEABlacklistingHandlerTasks<class ctkEACleanBlackList,class ctkEACacheTopicHandlerFilters<class ctkEALeastRecentlyUsedCacheMap<class QString,class QString> >,class ctkEACacheFilters<class ctkEALeastRecentlyUsedCacheMap<class QString,class ctkLDAPSearchFilter> > >::blackListRef, E:\CodeDevelopment\CTK\CTK-master\Plugins\org.commontk.eventadmin\handler\ctkEABlacklistingHandlerTasks.tpp:104
BlogEventHandler::handleEvent737
EventHandler received777 : title: "blog.title" content: "blog.content" 0x490c

---

I want to use synchronization to achieve this. Is there any other solution？

---

plugin --BlogEventHandler code:

---

blog_even_thandler_activator.h:

#ifndef BLOGEVENTHANDLERACTIVATOR_H
#define BLOGEVENTHANDLERACTIVATOR_H

#include <QObject>
#include "ctkPluginActivator.h"
#include "blog_event_handler.h"
class BlogEventHandlerActivator : public QObject,public ctkPluginActivator
{
    Q_OBJECT
    Q_INTERFACES(ctkPluginActivator)
    Q_PLUGIN_METADATA(IID "BLOG_EVENT_HANDLER")

public:
    void start(ctkPluginContext* context);
    void stop(ctkPluginContext* context);

private:
    BlogEventHandler* pEventHandler;

};

#endif // BLOGEVENTHANDLERACTIVATOR_H

blog_even_thandler_activator.cpp

#include "blog_even_thandler_activator.h"
#include "service/event/ctkEventConstants.h"
void BlogEventHandlerActivator::start(ctkPluginContext* context)
{
    qDebug()<<"BlogEventHandlerActivator::start";

    pEventHandler = new BlogEventHandler();
   pEventHandler->m_pContext = context;
   pEventHandler->init();

    ctkDictionary props;
    props[ctkEventConstants::EVENT_TOPIC] = "liborg/commontk/bloggenerator/published";
    ctkServiceReference ref = context->getServiceReference<ctkEventAdmin>();
    if (ref) {
     ctkEventAdmin* eventAdmin = context->getService<ctkEventAdmin>(ref);
     eventAdmin->subscribeSlot(pEventHandler, SLOT(onBlogPublished(ctkEvent)),
                               props,Qt::DirectConnection);
    }

}

void BlogEventHandlerActivator::stop(ctkPluginContext* context)
{
    Q_UNUSED(context)
    qDebug()<<"BlogEventHandlerActivator::stop";

    delete pEventHandler;
}

blog_event_handler.h

#ifndef BLOG_EVENT_HANDLER_H
#define BLOG_EVENT_HANDLER_H

#include <QObject>
#include <QThread>
#include <service/event/ctkEventHandler.h>
#include <service/event/ctkEventAdmin.h>

#include <ctkPluginContext.h>


class BlogEventHandler : public QObject, public ctkEventHandler
{
    Q_OBJECT
    Q_INTERFACES(ctkEventHandler)

public:
    ctkPluginContext* m_pContext;
    void init()
    {
        ctkServiceReference ref = m_pContext->getServiceReference<ctkEventAdmin>();
        if (ref) {
            ctkEventAdmin* eventAdmin = m_pContext->getService<ctkEventAdmin>(ref);
            eventAdmin->publishSignal(this, SIGNAL(blogPublished(ctkDictionary)),
                "liborg/commontk/bloggenerator/published1",Qt::DirectConnection);
        }
    }

    void handleEvent(const ctkEvent& event) Q_DECL_OVERRIDE
    {
        static int i =0;
        i++;
        qDebug()<<"BlogEventHandler::handleEvent1"<< i;

        if(i==2)
        {
            i=0;
            return;
        }

        QString title = event.getProperty("title").toString();
        QString content = event.getProperty("content").toString();
        QString author = event.getProperty("author").toString();

        qDebug() << "EventHandler received1 :" << "title:" << title  <<QThread::currentThreadId();

        ctkServiceReference ref = m_pContext->getServiceReference<ctkEventAdmin>();
        if (ref) {
            ctkEventAdmin* eventAdmin = m_pContext->getService<ctkEventAdmin>(ref);

            ctkDictionary props;
            props["title"] = "blog.title";
            props["content"] = "blog.content";
            props["author"] = "blog.author";

            blogPublished(props);
        }
    }

 public slots:
    // 处理事件
    void onBlogPublished(const ctkEvent& event)
    {
        static int i =0;
        i++;
        qDebug()<<"BlogEventHandler::handleEvent"<< i;

        if(i==2)
        {
            i=0;
            return;
        }

        QThread::msleep(500);
        QString title = event.getProperty("title").toString();
        QString content = event.getProperty("content").toString();
        QString author = event.getProperty("author").toString();

        qDebug() << "EventHandler received :" << "title:" << title  <<QThread::currentThreadId();

        ctkServiceReference ref = m_pContext->getServiceReference<ctkEventAdmin>();
        if (ref) {
            ctkEventAdmin* eventAdmin = m_pContext->getService<ctkEventAdmin>(ref);

            ctkDictionary props;
            props["title"] = "blog.title";
            props["content"] = "blog.content";
            props["author"] = "blog.author";

            blogPublished(props);
        }
    }

signals:
    void blogPublished(const ctkDictionary&);
};

#endif // BLOG_EVENT_HANDLER_H

---

plugin --BlogManager code:

---

blog_manager.h

#ifndef BLOG_MANAGER_H
#define BLOG_MANAGER_H

#include <QObject>
#include <ctkPluginContext.h>
#include <QThread>
#include <service/event/ctkEventHandler.h>

typedef struct Blog_Info {
    QString title;
    QString author;
    QString content;
} Blog;
 
class BlogManager: public QObject, public ctkEventHandler
{
    Q_OBJECT
    Q_INTERFACES(ctkEventHandler)

public:
    BlogManager(ctkPluginContext* context); 
    void publishBlog(const Blog& blog); 
    void handleEvent(const ctkEvent& event) Q_DECL_OVERRIDE ;

private:
    ctkPluginContext* m_pContext;

signals:
 void blogPublished(const ctkDictionary&);
};

#endif // BLOG_MANAGER_H

blog_manager.cpp

#include "blog_manager.h"
#include <service/event/ctkEventAdmin.h>
#include <QtDebug>
#include <QtConcurrent/QtConcurrent>

BlogManager::BlogManager(ctkPluginContext* context)
    : m_pContext(context)
{
    ctkServiceReference ref = context->getServiceReference<ctkEventAdmin>();
     if (ref) {
     ctkEventAdmin* eventAdmin = context->getService<ctkEventAdmin>(ref);
     eventAdmin->publishSignal(this, SIGNAL(blogPublished(ctkDictionary)),
                               "liborg/commontk/bloggenerator/published",Qt::DirectConnection);
     }

}
 
void BlogManager::publishBlog(const Blog& blog)
{
    qDebug()<<"BlogManager::publishBlog";

    ctkServiceReference ref = m_pContext->getServiceReference<ctkEventAdmin>();
    if (ref) {
        ctkEventAdmin* eventAdmin = m_pContext->getService<ctkEventAdmin>(ref);

        ctkDictionary props;
        props["title"] = blog.title+"7771";
        props["content"] = blog.content;
        props["author"] = blog.author;
        ctkEvent event("liborg/commontk/bloggenerator/published", props);


        qDebug() << "start run:" <<QThread::currentThreadId();
        QFuture<void> future = QtConcurrent::run([=]() {
            qDebug() << "QFuture run:" <<QThread::currentThreadId();
            emit blogPublished(props);
        });
        future.waitForFinished();
        qDebug()<<"run over!";
    }
    else
    {
        qDebug()<<"error service";
    }
}

void BlogManager::handleEvent(const ctkEvent& event)
{
    qDebug()<<"BlogEventHandler::handleEvent757";

    QString title = event.getProperty("title").toString();
    QString content = event.getProperty("content").toString();
    QString author = event.getProperty("author").toString();

    qDebug() << "EventHandler received777 :" << "title:" << title << "content:" << content  <<QThread::currentThreadId();
}

blog_manager_activator.h

#ifndef BLOG_MANAGER_ACTIVATOR_H
#define BLOG_MANAGER_ACTIVATOR_H

#include <ctkPluginActivator.h>
//#include "blog_ann_handler.h"


class BlogManager;

class BlogManagerActivator : public QObject, public ctkPluginActivator
{
    Q_OBJECT
    Q_INTERFACES(ctkPluginActivator)
    Q_PLUGIN_METADATA(IID "BLOG_MANAGER")

public:
    void start(ctkPluginContext* context);
    void stop(ctkPluginContext* context);

private:
    BlogManager *m_pBlogManager;
};

#endif // BLOG_MANAGER_ACTIVATOR_H

blog_manager_activator.cpp

#include "blog_manager.h"
#include "blog_manager_activator.h"
#include <QtDebug>
#include <QTimer>
void BlogManagerActivator::start(ctkPluginContext* context)
{


    qDebug()<<"BlogManagerActivator::start";

    m_pBlogManager = new BlogManager(context);


    QTimer* _timer = new QTimer(this);
    _timer->setSingleShot(true);
    connect(_timer, &QTimer::timeout,  [=]()
    {
        Blog blog;
        blog.title = "CTK Event Admin";
        blog.content = "This is a simple blog";
        blog.author = "HBing110";
        m_pBlogManager->publishBlog(blog);
    });
    _timer->start(1000);
}

void BlogManagerActivator::stop(ctkPluginContext* context)
{

    qDebug()<<"BlogManagerActivator::stop";

    Q_UNUSED(context)

    delete m_pBlogManager;
}

---

plugin --BlogManager1 code:

---

blog_manager.h

#ifndef BLOG_MANAGER_H
#define BLOG_MANAGER_H

#include <QObject>
#include <ctkPluginContext.h>
#include <QThread>
#include <service/event/ctkEventHandler.h>

typedef struct Blog_Info {
    QString title;
    QString author;
    QString content;
} Blog;
 
class BlogManager: public QObject
{
    Q_OBJECT

public:
    BlogManager(ctkPluginContext* context);

public slots: 
    void onBlogPublished(const ctkEvent& event);
private:
    ctkPluginContext* m_pContext;
};

#endif // BLOG_MANAGER_H

blog_manager.cpp

#include "blog_manager.h"
#include <service/event/ctkEventAdmin.h>
#include <QtDebug> 
#include "service/event/ctkEventConstants.h"
BlogManager::BlogManager(ctkPluginContext* context)
    : m_pContext(context)
{
    ctkDictionary props;
    props[ctkEventConstants::EVENT_TOPIC] = "liborg/commontk/bloggenerator/published1";
    ctkServiceReference ref = context->getServiceReference<ctkEventAdmin>();
    if (ref) {
        ctkEventAdmin* eventAdmin = context->getService<ctkEventAdmin>(ref);
        eventAdmin->subscribeSlot(this, SLOT(onBlogPublished(ctkEvent)),
                                  props,Qt::DirectConnection);
    }
}
 
void BlogManager::onBlogPublished(const ctkEvent& event)
{
    qDebug() << "BlogEventHandler::handleEvent737";

    QString title = event.getProperty("title").toString();
    QString content = event.getProperty("content").toString();
    QString author = event.getProperty("author").toString();

    qDebug() << "EventHandler received777 :" << "title:" << title << "content:" << content << QThread::currentThreadId();

}

blog_manager_activator.h

#ifndef BLOG_MANAGER_ACTIVATOR_H
#define BLOG_MANAGER_ACTIVATOR_H

#include <ctkPluginActivator.h>
//#include "blog_ann_handler.h"


class BlogManager;

class BlogManagerActivator : public QObject, public ctkPluginActivator
{
    Q_OBJECT
    Q_INTERFACES(ctkPluginActivator)
    Q_PLUGIN_METADATA(IID "BLOG_MANAGER11")

public:
    void start(ctkPluginContext* context);
    void stop(ctkPluginContext* context);

private:
    BlogManager *m_pBlogManager;
};

#endif // BLOG_MANAGER_ACTIVATOR_H

blog_manager_activator.cpp

#include "blog_manager.h"
#include "blog_manager_activator.h"
#include <QtDebug>
#include <QTimer>
void BlogManagerActivator::start(ctkPluginContext* context)
{


    qDebug()<<"BlogManagerActivator::start";

    m_pBlogManager = new BlogManager(context);

}

void BlogManagerActivator::stop(ctkPluginContext* context)
{

    qDebug()<<"BlogManagerActivator::stop";

    Q_UNUSED(context)

    delete m_pBlogManager;
}

---

test program

main.cpp

#include <QCoreApplication>
#include "ctkPluginException.h"
#include "ctkPluginContext.h"
#include <QDirIterator>
#include <QDebug>
#include "ctkPluginFrameworkLauncher.h"

int main(int argc, char *argv[])
{
    QCoreApplication app(argc, argv);

    QString path = QCoreApplication::applicationDirPath() + "/plugins";

    ctkPluginFrameworkLauncher::addSearchPath("./../ctk-0.1/plugins");
 
    ctkPluginFrameworkLauncher::start("org.commontk.eventadmin"); 
    ctkPluginContext* context = ctkPluginFrameworkLauncher::getPluginContext();

 
    try {
        QSharedPointer<ctkPlugin> plugin = context->installPlugin(QUrl::fromLocalFile(path + "/BlogEventHandler.dll"));
        plugin->start();
        qDebug() << "BlogEventHandler start ...";
    } catch (const ctkPluginException &e) {
        qDebug() << "Failed to start BlogEventHandler" << e.what();
    }

    try {
        QSharedPointer<ctkPlugin> plugin = context->installPlugin(QUrl::fromLocalFile(path + "/BlogManager.dll"));
        plugin->start();

        qDebug() << "BlogManager start ...";
    } catch (const ctkPluginException &e) {
        qDebug() << "Failed to start BlogManager" << e.what();
    }

 
   try {
       QSharedPointer<ctkPlugin> plugin = context->installPlugin(QUrl::fromLocalFile(path + "/BlogManager1.dll"));
       plugin->start();

       qDebug() << "BlogManager1 start ...";
   } catch (const ctkPluginException &e) {
       qDebug() << "Failed to start BlogManager1" << e.what();
   }

    qDebug() << "***************";



    return app.exec();
    return 1;
}

[jcfr]

Thanks for the report

To help the community better understand the problem and answer your question, could you create a standalone project on GitHub allowing to reproduce the issue ?