SunSpec: Improve discovery and handle blocking connections

debian/compat

@@ -1 +1 @@
-9
+10

sunspec/sunspecdiscovery.cpp

@@ -94,7 +94,31 @@ void SunSpecDiscovery::testNextConnection(const QHostAddress &address)
     if (!connection->connectDevice()) {
         qCDebug(dcSunSpec()) << "Discovery: Failed to connect to" << QString("%1:%2").arg(address.toString()).arg(connection->port()) << "slave ID:" << connection->slaveId() << "Continue...";;
         cleanupConnection(connection);
+        return;
     }
+
+    /* Some connection will block the connection process and the connection will pending in the
+     * connecting state for over a minute before failing.
+     * This behavior blocks further connection tests for during the disdovery process and the discovery failes to detect the device.
+     * This timer will make sure the connection can be established within 5 seconds, otherwise we continue with the next connection.
+     */
+
+    QTimer *connectionTimer = new QTimer(connection);
+    connectionTimer->setInterval(5000);
+    connectionTimer->setSingleShot(true);
+
+    m_connectionTimers.insert(connection, connectionTimer);
+
+    connect(connectionTimer, &QTimer::timeout, connection, [this, connection, connectionTimer](){
+        qCDebug(dcSunSpec()) << "Discovery: Could not establish a connection within" << connectionTimer->interval() << "ms. Continue...";
+        m_connectionTimers.remove(connection);
+        connection->disconnectDevice();
+        // Note: since the connection is the parent of the timer, it will be deleted with the connection
+        cleanupConnection(connection);
+    });
+
+    // Once connected, the timer will be stopped.
+    connectionTimer->start();
 }
 
 void SunSpecDiscovery::checkNetworkDevice(const NetworkDeviceInfo &networkDeviceInfo)
@@ -121,6 +145,13 @@ void SunSpecDiscovery::checkNetworkDevice(const NetworkDeviceInfo &networkDevice
                     return;
                 }
 
+                // Successfully connected, we can stop the connection timer which takes care about blocking connection attempts
+                if (m_connectionTimers.contains(connection)) {
+                    QTimer *connectionTimer = m_connectionTimers.take(connection);
+                    connectionTimer->stop();
+                    connectionTimer->deleteLater();
+                }
+
                 // Modbus TCP connected, try to discovery sunspec models...
                 connect(connection, &SunSpecConnection::discoveryFinished, this, [=](bool success){
                     if (!success) {
@@ -180,6 +211,11 @@ void SunSpecDiscovery::cleanupConnection(SunSpecConnection *connection)
     connection->disconnectDevice();
     connection->deleteLater();
 
+    if (m_connectionTimers.contains(connection)) {
+        QTimer *connectionTimer = m_connectionTimers.take(connection);
+        connectionTimer->stop();
+    }
+
     testNextConnection(connection->hostAddress());
 }
 

sunspec/sunspecdiscovery.h

@@ -66,6 +66,7 @@ private:
 
     QDateTime m_startDateTime;
     QHash<QHostAddress, QQueue<SunSpecConnection *>> m_pendingConnectionAttempts;
+    QHash<SunSpecConnection *, QTimer *> m_connectionTimers;
 
     QList<SunSpecConnection *> m_connections;
     QList<Result> m_results;