feat(gui): Retry mechanism for Windows Daemon IPC client

src/lib/gui/MainWindow.cpp

@@ -289,7 +289,9 @@ void MainWindow::connectSlots()
   connect(&m_coreProcess, &CoreProcess::processStateChanged, this, &MainWindow::coreProcessStateChanged);
   connect(&m_coreProcess, &CoreProcess::connectionStateChanged, this, &MainWindow::coreConnectionStateChanged);
   connect(&m_coreProcess, &CoreProcess::secureSocket, this, &MainWindow::secureSocket);
-  connect(&m_coreProcess, &CoreProcess::daemonIpcClientConnectFailed, this, &MainWindow::daemonIpcClientConnectFailed);
+  connect(
+      &m_coreProcess, &CoreProcess::daemonIpcClientConnectionFailed, this, &MainWindow::daemonIpcClientConnectionFailed
+  );
 
   connect(m_actionAbout, &QAction::triggered, this, &MainWindow::openAboutDialog);
   connect(m_actionClearSettings, &QAction::triggered, this, &MainWindow::clearSettings);
@@ -1145,7 +1147,7 @@ bool MainWindow::regenerateLocalFingerprints()
   return true;
 }
 
-void MainWindow::daemonIpcClientConnectFailed()
+void MainWindow::daemonIpcClientConnectionFailed()
 {
   if (deskflow::gui::messages::showDaemonOffline(this)) {
     m_coreProcess.retryDaemon();

src/lib/gui/MainWindow.h

@@ -158,7 +158,7 @@ private:
   void showAndActivate();
   void showHostNameEditor();
   void setHostName();
-  void daemonIpcClientConnectFailed();
+  void daemonIpcClientConnectionFailed();
   void toggleCanRunCore(bool enableButtons);
   void remoteHostChanged(const QString newRemoteHost);
 

src/lib/gui/core/CoreProcess.cpp

@@ -140,7 +140,9 @@ CoreProcess::CoreProcess(const IServerConfig &serverConfig, std::shared_ptr<Deps
       m_daemonIpcClient{new ipc::DaemonIpcClient(this)}
 {
   connect(m_daemonIpcClient, &ipc::DaemonIpcClient::connected, this, &CoreProcess::daemonIpcClientConnected);
-  connect(m_daemonIpcClient, &ipc::DaemonIpcClient::connectFailed, this, &CoreProcess::daemonIpcClientConnectFailed);
+  connect(
+      m_daemonIpcClient, &ipc::DaemonIpcClient::connectionFailed, this, &CoreProcess::daemonIpcClientConnectionFailed
+  );
 
   connect(&m_pDeps->process(), &QProcessProxy::finished, this, &CoreProcess::onProcessFinished);
 

src/lib/gui/core/CoreProcess.h

@@ -120,7 +120,7 @@ signals:
   void connectionStateChanged(ConnectionState state);
   void processStateChanged(ProcessState state);
   void secureSocket(bool enabled);
-  void daemonIpcClientConnectFailed();
+  void daemonIpcClientConnectionFailed();
 
 private slots:
   void onProcessFinished(int exitCode, QProcess::ExitStatus);

src/lib/gui/ipc/DaemonIpcClient.cpp

@@ -16,6 +16,7 @@
 namespace deskflow::gui::ipc {
 
 const auto kTimeout = 1000;
+const auto kRetryLimit = 3;
 
 DaemonIpcClient::DaemonIpcClient(QObject *parent)
     : QObject(parent),
@@ -27,54 +28,95 @@ DaemonIpcClient::DaemonIpcClient(QObject *parent)
 
 bool DaemonIpcClient::connectToServer()
 {
-  if (m_connecting) {
+  if (m_state == State::Connecting) {
-    qDebug() << "daemon ipc client already connecting to server";
+    qWarning() << "daemon ipc client already connecting to server";
     return false;
   }
 
-  qDebug() << "daemon ipc client connecting to server:" << kDaemonIpcName;
+  if (m_state != State::Unconnected) {
-  m_connecting = true;
+    qDebug() << "daemon ipc client not in unconnected state, disconnecting";
-  m_socket->connectToServer(kDaemonIpcName);
+    disconnectFromServer();
-
-  if (!m_socket->waitForConnected(kTimeout)) {
-    qWarning() << "daemon ipc client failed to connect";
-    m_connecting = false;
-    Q_EMIT connectFailed();
-    return false;
   }
 
-  if (!sendMessage("hello", "hello", false)) {
+  if (m_socket->state() != QLocalSocket::UnconnectedState) {
-    qWarning() << "daemon ipc client failed to send hello";
+    qWarning() << "daemon ipc client socket not in unconnected state, disconnecting";
-    m_connecting = false;
+    disconnectFromServer();
-    Q_EMIT connectFailed();
-    return false;
   }
 
-  m_connecting = false;
+  for (int i = 0; i < kRetryLimit; ++i) {
-  m_connected = true;
+    if (i == 0) {
+      qDebug() << "daemon ipc client connecting to server:" << kDaemonIpcName;
+    } else {
+      qDebug() << "daemon ipc client retrying connection, attempt:" << i + 1;
+    }
 
-  qDebug() << "daemon ipc client connected";
+    m_state = State::Connecting;
-  Q_EMIT connected();
+    m_socket->connectToServer(kDaemonIpcName);
 
-  return true;
+    if (!m_socket->waitForConnected(kTimeout)) {
+      qWarning() << "daemon ipc client failed to connect";
+      disconnectFromServer();
+      continue;
+    }
+
+    if (!sendMessage("hello", "hello", false)) {
+      qWarning() << "daemon ipc client failed to send hello";
+      disconnectFromServer();
+      continue;
+    }
+
+    m_state = State::Connected;
+    qDebug() << "daemon ipc client connected";
+    Q_EMIT connected();
+    return true;
+  }
+
+  qWarning() << "daemon ipc client failed to connect after" << kRetryLimit << "attempts";
+  disconnectFromServer();
+  Q_EMIT connectionFailed();
+  return false;
+}
+
+void DaemonIpcClient::disconnectFromServer()
+{
+  m_state = State::Disconnecting;
+  qDebug() << "daemon ipc client disconnecting from server";
+  m_socket->disconnectFromServer();
+
+  if (m_socket->state() != QLocalSocket::UnconnectedState) {
+    qDebug() << "daemon ipc client waiting for socket to disconnect";
+    m_socket->waitForDisconnected(kTimeout);
+    qDebug() << "daemon ipc client disconnected from server";
+  } else {
+    qDebug() << "daemon ipc client socket already disconnected";
+  }
+
+  m_state = State::Unconnected;
 }
 
 void DaemonIpcClient::handleDisconnected()
 {
-  qWarning() << "daemon ipc client disconnected from server";
+  qDebug() << "daemon ipc client disconnected from server";
-  m_connected = false;
+  if (m_state == State::Connected) {
-  Q_EMIT connectFailed();
+    Q_EMIT connectionFailed();
+  }
+
+  m_state = State::Unconnected;
 }
 
 void DaemonIpcClient::handleErrorOccurred()
 {
   qWarning() << "daemon ipc client error:" << m_socket->errorString();
-  m_connected = false;
+  disconnectFromServer();
+
+  if (m_state == State::Connected) {
+    Q_EMIT connectionFailed();
+  }
 }
 
 bool DaemonIpcClient::sendMessage(const QString &message, const QString &expectAck, const bool expectConnected)
 {
-  if (expectConnected && !m_connected) {
+  if (expectConnected && !isConnected()) {
     qWarning() << "cannot send command, ipc client not connected";
     return false;
   }
@@ -90,7 +132,7 @@ bool DaemonIpcClient::sendMessage(const QString &message, const QString &expectA
     qDebug() << "daemon ipc client waiting for ack: " << expectAck;
 
     if (!m_socket->waitForReadyRead(kTimeout)) {
-      qWarning() << "daemon ipc client failed to read response";
+      qWarning() << "daemon ipc client socket ready read timed out";
       return false;
     }
 
@@ -124,8 +166,8 @@ bool DaemonIpcClient::keepAlive()
   }
 
   if (!sendMessage("noop")) {
-    qWarning() << "daemon ipc client keep alive ping failed";
+    qWarning() << "daemon ipc client keep alive ping failed, reconnecting";
-    m_connected = false;
+    connectToServer();
     return false;
   }
 

src/lib/gui/ipc/DaemonIpcClient.h

@@ -16,9 +16,19 @@ class DaemonIpcClient : public QObject
 {
   Q_OBJECT
 
+  // Represents underlying socket state and whether the server responded to the hello message.
+  enum class State
+  {
+    Unconnected,
+    Connecting,
+    Connected,
+    Disconnecting,
+  };
+
 public:
   explicit DaemonIpcClient(QObject *parent = nullptr);
   bool connectToServer();
+  void disconnectFromServer();
   bool sendLogLevel(const QString &logLevel);
   bool sendStartProcess(const QString &command, bool elevate);
   bool sendStopProcess();
@@ -27,12 +37,12 @@ public:
 
   bool isConnected() const
   {
-    return m_connected;
+    return m_state == State::Connected;
   }
 
 signals:
   void connected();
-  void connectFailed();
+  void connectionFailed();
 
 private slots:
   void handleDisconnected();
@@ -44,8 +54,7 @@ private:
 
 private:
   QLocalSocket *m_socket;
-  bool m_connected{false};
+  State m_state{State::Unconnected};
-  bool m_connecting{false};
 };
 
 } // namespace deskflow::gui::ipc

src/lib/platform/MSWindowsWatchdog.cpp

@@ -246,7 +246,7 @@ void MSWindowsWatchdog::mainLoop(void *)
   LOG_DEBUG("watchdog main loop finished");
 
   if (m_process != nullptr) {
-    LOG_DEBUG("terminated running process on exit");
+    LOG_DEBUG("terminating running process on exit");
     m_process->shutdown();
     m_process.reset();
   }