update: Ensure we never have two update processes running in parallel

update/CMakeLists.txt

 add_executable(plasma-discover-update main.cpp DiscoverUpdate.cpp)
 
 set_target_properties(plasma-discover-update PROPERTIES INSTALL_RPATH ${CMAKE_INSTALL_FULL_LIBDIR}/plasma-discover)
-target_link_libraries(plasma-discover-update Discover::Common KF5::CoreAddons KF5::I18n)
+target_link_libraries(plasma-discover-update Discover::Common KF5::CoreAddons KF5::I18n KF5::DBusAddons)
 
 install(TARGETS plasma-discover-update ${KDE_INSTALL_TARGETS_DEFAULT_ARGS})

update/main.cpp

@@ -8,6 +8,7 @@
 #include "DiscoverUpdate.h"
 #include <DiscoverBackendsFactory.h>
 #include <KAboutData>
+#include <KDBusService>
 #include <KLocalizedString>
 #include <QCommandLineParser>
 #include <QGuiApplication>
@@ -22,6 +23,8 @@ int main(int argc, char **argv)
     about.setProductName("discover/update");
     KAboutData::setApplicationData(about);
 
+    KDBusService service(KDBusService::Unique);
+
     DiscoverUpdate exp;
     {
         QCommandLineParser parser;