settings apply: catch exceptions and show them to the user

Settings are applied in separate thread, so when any exception occured there,
the user had no way to know it (besides hanging "applying settings" window).

qubesmanager/settings.py

@@ -154,28 +154,48 @@ class VMSettingsWindow(Ui_SettingsDialog, QDialog):
         self.qvm_collection.lock_db_for_writing()
         self.anything_changed = False
         
-        ret = self.__apply_basic_tab__()
+        ret = []
-        self.__apply_advanced_tab__()
+        try:
-        self.__apply_devices_tab__()
+            ret_tmp = self.__apply_basic_tab__()
-        self.__apply_services_tab__()
+            if len(ret_tmp) > 0:
-
+                ret += ["Basic tab:"] + ret_tmp
-        if len(ret) > 0 :
+            ret_tmp = self.__apply_advanced_tab__()
-            thread_monitor.set_error_msg('\n'.join(ret)) 
+            if len(ret_tmp) > 0:
+                ret += ["Advanced tab:"] + ret_tmp
+            ret_tmp = self.__apply_devices_tab__()
+            if len(ret_tmp) > 0:
+                ret += ["Devices tab:"] + ret_tmp
+            ret_tmp = self.__apply_services_tab__()
+            if len(ret_tmp) > 0:
+                ret += ["Sevices tab:"] + ret_tmp
+        except Exception as ex:
+            ret.append('Error while saving changes: ' + str(ex))
 
         if self.anything_changed == True:
             self.qvm_collection.save()
         self.qvm_collection.unlock_db()
 
+        try:
             if self.tabWidget.isTabEnabled(self.tabs_indices["firewall"]):
-            self.fw_model.apply_rules(self.policyAllowRadioButton.isChecked(), self.dnsCheckBox.isChecked(), self.icmpCheckBox.isChecked(), self.yumproxyCheckBox.isChecked())
+                self.fw_model.apply_rules(self.policyAllowRadioButton.isChecked(),
+                        self.dnsCheckBox.isChecked(),
+                        self.icmpCheckBox.isChecked(),
+                        self.yumproxyCheckBox.isChecked())
+        except Exception as ex:
+            ret += ["Firewall tab:", str(ex)]
 
+        try:
             if self.tabWidget.isTabEnabled(self.tabs_indices["applications"]):
                 self.AppListManager.save_appmenu_select_changes()
+        except Exception as ex:
+            ret += ["Applications tab:", str(ex)]
+
+        if len(ret) > 0 :
+            thread_monitor.set_error_msg('\n'.join(ret))
 
         thread_monitor.set_finished()
 
 
-
     def current_tab_changed(self, idx):
         if idx == self.tabs_indices["firewall"]:
             if self.vm.netvm is not None and not self.vm.netvm.is_proxyvm():
@@ -303,13 +323,17 @@ class VMSettingsWindow(Ui_SettingsDialog, QDialog):
                     msg.append(str(ex))
 
         #vm label changed
+        try:
             if self.vmlabel.isVisible():
                 if self.vmlabel.currentIndex() != self.label_idx:
                     label = self.label_list[self.vmlabel.currentIndex()]
                     self.vm.label = label
                     self.anything_changed = True
+        except Exception as ex:
+            msg.append(str(ex))
 
         #vm template changed
+        try:
             if self.template_name.currentIndex() != self.template_idx:
                 new_template_name = self.template_name.currentText()
                 new_template_name = new_template_name.split(' ')[0]
@@ -318,8 +342,11 @@ class VMSettingsWindow(Ui_SettingsDialog, QDialog):
                 assert template_vm.is_template()
                 self.vm.template = template_vm
                 self.anything_changed = True
+        except Exception as ex:
+            msg.append(str(ex))
 
         #vm netvm changed
+        try:
             if self.netVM.currentIndex() != self.netvm_idx:
                 new_netvm_name = self.netVM.currentText()
                 new_netvm_name = new_netvm_name.split(' ')[0]
@@ -339,17 +366,25 @@ class VMSettingsWindow(Ui_SettingsDialog, QDialog):
                 self.vm.netvm = netvm
                 self.vm.uses_default_netvm = uses_default_netvm
                 self.anything_changed = True
+        except Exception as ex:
+            msg.append(str(ex))
 
         #include in backups
+        try:
             if self.vm.include_in_backups != self.include_in_backups.isChecked():
                 self.vm.include_in_backups = self.include_in_backups.isChecked()
                 self.anything_changed = True
+        except Exception as ex:
+            msg.append(str(ex))
 
         #run_in_debug_mode
+        try:
             if self.run_in_debug_mode.isVisible():
                 if self.vm.debug != self.run_in_debug_mode.isChecked():
                     self.vm.debug = self.run_in_debug_mode.isChecked()
                     self.anything_changed = True
+        except Exception as ex:
+            msg.append(str(ex))
 
         #max priv storage
         priv_size = self.max_priv_storage.value()
@@ -449,8 +484,10 @@ class VMSettingsWindow(Ui_SettingsDialog, QDialog):
                 
        
     def __apply_advanced_tab__(self):
+        msg = []
 
         #mem/cpu
+        try:
             if self.init_mem.value() != int(self.vm.memory):
                 self.vm.memory = self.init_mem.value()
                 self.anything_changed = True
@@ -462,18 +499,21 @@ class VMSettingsWindow(Ui_SettingsDialog, QDialog):
             if self.vcpus.value() != int(self.vm.vcpus):
                 self.vm.vcpus = self.vcpus.value()
                 self.anything_changed = True
+        except Exception as ex:
+            msg.append(str(ex))
 
         #include_in_memory_balancing applied in services tab
 
 
         #in case VM is not Linux
         if not hasattr(self.vm, "kernel"):
-            return;
+            return msg;
 
         #kernel changed
         if not self.kernel_groupbox.isVisible():
-            return
+            return msg
 
+        try:
             if self.kernel.currentIndex() != self.kernel_idx:
                 new_kernel = self.kernel.currentText()
                 new_kernel = new_kernel.split(' ')[0]
@@ -489,6 +529,10 @@ class VMSettingsWindow(Ui_SettingsDialog, QDialog):
 
                 self.vm.kernel = kernel
                 self.anything_changed = True
+        except Exception as ex:
+            msg.append(str(ex))
+
+        return msg
 
 
     ######## devices tab
@@ -528,9 +572,11 @@ class VMSettingsWindow(Ui_SettingsDialog, QDialog):
 
 
     def __apply_devices_tab__(self):
+        msg = []
         sth_changed = False
         added = []
 
+        try:
             for i in range(self.dev_list.selected_list.count()):
                 item = self.dev_list.selected_list.item(i)
                 if item.slot not in self.vm.pcidevs:
@@ -548,6 +594,10 @@ class VMSettingsWindow(Ui_SettingsDialog, QDialog):
                     pcidevs.append(slot)
                 self.vm.pcidevs = pcidevs
                 self.anything_changed = True
+        except Exception as ex:
+            msg.append(str(ex))
+
+        return msg
 
     def include_in_balancing_state_changed(self, state):
         for r in range (self.services_list.count()):
@@ -619,6 +669,9 @@ class VMSettingsWindow(Ui_SettingsDialog, QDialog):
 
 
     def __apply_services_tab__(self):
+        msg = []
+
+        try:
             for r in range (self.services_list.count()):
                 item = self.services_list.item(r)
                 self.new_srv_dict[str(item.text())] = (item.checkState() == QtCore.Qt.Checked)
@@ -634,6 +687,10 @@ class VMSettingsWindow(Ui_SettingsDialog, QDialog):
             if self.new_srv_dict != self.vm.services:
                 self.vm.services = self.new_srv_dict
                 self.anything_changed = True
+        except Exception as ex:
+            msg.append(str(ex))
+
+        return msg
 
 
     ######### firewall tab related