Move opening of connections into a background thread to avoid locking the UI

src/virtManager/connection.py

@@ -26,6 +26,8 @@ from time import time
 import logging
 from socket import gethostbyaddr, gethostname
 import dbus
+import threading
+import gtk
 
 from virtManager.domain import vmmDomain
 from virtManager.network import vmmNetwork
@@ -96,6 +98,8 @@ class vmmConnection(gobject.GObject):
                               []),
         "state-changed": (gobject.SIGNAL_RUN_FIRST, gobject.TYPE_NONE,
                           []),
+        "connect-error": (gobject.SIGNAL_RUN_FIRST, gobject.TYPE_NONE,
+                          [str]),
         }
 
     STATE_DISCONNECTED = 0
@@ -108,6 +112,8 @@ class vmmConnection(gobject.GObject):
         self.config = config
         self.readOnly = readOnly
 
+        self.connectThread = None
+        self.connectError = None
         self.uri = uri
         if self.uri is None or self.uri.lower() == "xen":
             self.uri = "xen:///"
@@ -279,6 +285,15 @@ class vmmConnection(gobject.GObject):
 
         self.state = self.STATE_CONNECTING
         self.emit("state-changed")
+
+        logging.debug("Scheduling background open thread for " + self.uri)
+        self.connectThread = threading.Thread(target = self._open_thread, name="Connect " + self.uri)
+        self.connectThread.setDaemon(True)
+        self.connectThread.start()
+
+
+    def _open_thread(self):
+        logging.debug("Background thread is running")
         try:
             if self.readOnly is None:
                 try:
@@ -293,12 +308,42 @@ class vmmConnection(gobject.GObject):
                 else:
                     self.vmm = libvirt.open(self.uri)
             self.state = self.STATE_ACTIVE
-            self.tick()
-            self.emit("state-changed")
         except:
             self.state = self.STATE_DISCONNECTED
+
+            (type, value, stacktrace) = sys.exc_info ()
+            # Detailed error message, in English so it can be Googled.
+            self.connectError = \
+                    ("Unable to open connection to hypervisor URI '%s':\n" %
+                     str(self.uri)) + \
+                    str(type) + " " + str(value) + "\n" + \
+                    traceback.format_exc (stacktrace)
+            logging.error(self.connectError)
+
+        # We want to kill off this thread asap, so schedule a gobject
+        # idle even to inform the UI of result
+        logging.debug("Background open thread complete, scheduling notify")
+        gtk.gdk.threads_enter()
+        try:
+            gobject.idle_add(self._open_notify)
+        finally:
+            gtk.gdk.threads_leave()
+        self.connectThread = None
+
+    def _open_notify(self):
+        logging.debug("Notifying open result")
+        gtk.gdk.threads_enter()
+        try:
+            if self.state == self.STATE_ACTIVE:
+                self.tick()
             self.emit("state-changed")
-            raise
+
+            if self.state == self.STATE_DISCONNECTED:
+                self.emit("connect-error", self.connectError)
+                self.connectError = None
+        finally:
+            gtk.gdk.threads_leave()
+
 
     def pause(self):
         if self.state != self.STATE_ACTIVE:

src/virtManager/engine.py

@@ -34,7 +34,6 @@ from virtManager.console import vmmConsole
 from virtManager.asyncjob import vmmAsyncJob
 from virtManager.create import vmmCreate
 from virtManager.serialcon import vmmSerialConsole
-from virtManager.error import vmmErrorDialog
 from virtManager.host import vmmHost
 
 class vmmEngine(gobject.GObject):
@@ -82,43 +81,6 @@ class vmmEngine(gobject.GObject):
             self.show_manager()
             return conn
         except:
-            (type, value, stacktrace) = sys.exc_info ()
-
-            # Detailed error message, in English so it can be Googled.
-            details = \
-                    ("Unable to open connection to hypervisor URI '%s':\n" %
-                     str(uri)) + \
-                    str(type) + " " + str(value) + "\n" + \
-                    traceback.format_exc (stacktrace)
-            logging.error (details)
-
-            # Error dialog.
-            if uri is None:
-                uri = "xen"
-            if uri == "xen":
-                dg = vmmErrorDialog (None, 0, gtk.MESSAGE_ERROR,
-                                     gtk.BUTTONS_CLOSE,
-                                     _("Unable to open a connection to the Xen hypervisor/daemon.\n\n" +
-                                       "Verify that:\n" +
-                                       " - A Xen host kernel was booted\n" +
-                                       " - The Xen service has been started\n"),
-                                     details)
-            elif uri.startswith("qemu:"):
-                dg = vmmErrorDialog (None, 0, gtk.MESSAGE_ERROR,
-                                     gtk.BUTTONS_CLOSE,
-                                     _("Unable to open a connection to the QEMU management daemon.\n\n" +
-                                       "Verify that:\n" +
-                                       " - The 'libvirt_qemud' daemon has been started\n"),
-                                     details)
-            else:
-                dg = vmmErrorDialog (None, 0, gtk.MESSAGE_ERROR,
-                                     gtk.BUTTONS_CLOSE,
-                                     _("Unable to open connection to hypervisor '%s'") % str(uri),
-                                     details)
-            dg.set_title(_("Virtual Machine Manager Connection Failure"))
-            dg.run()
-            dg.hide()
-            dg.destroy()
             return None
 
     def _connect_cancelled(self, connect):

src/virtManager/manager.py

@@ -22,13 +22,14 @@ import gtk
 import gtk.glade
 import threading
 import logging
+import sys
 
 import sparkline
 import libvirt
 
 from virtManager.connection import vmmConnection
 from virtManager.asyncjob import vmmAsyncJob
-
+from virtManager.error import vmmErrorDialog
 
 VMLIST_SORT_ID = 1
 VMLIST_SORT_NAME = 2
@@ -503,7 +504,7 @@ class vmmManager(gobject.GObject):
         row[ROW_VCPUS] = conn.host_active_processor_count()
         row[ROW_MEM] = conn.pretty_current_memory()
         row[ROW_MEM_USAGE] = conn.current_memory_percentage()
-        if conn.get_state() == vmmConnection.STATE_DISCONNECTED:
+        if conn.get_state() in [vmmConnection.STATE_DISCONNECTED, vmmConnection.STATE_CONNECTING]:
             row[ROW_ACTION] = gtk.STOCK_DELETE
             parent = self.rows[conn.get_uri()].iter
             if parent is not None:
@@ -942,6 +943,7 @@ class vmmManager(gobject.GObject):
         conn.connect("vm-removed", self.vm_removed)
         conn.connect("resources-sampled", self.conn_refresh_resources)
         conn.connect("state-changed", self.conn_state_changed)
+        conn.connect("connect-error", self._connect_error)
         conn.connect("vm-started", self.vm_started)
         # add the connection to the treeModel
         vmlist = self.window.get_widget("vm-list")
@@ -970,4 +972,26 @@ class vmmManager(gobject.GObject):
         logging.debug("Deactivating connection %s" % conn.get_uri())
         conn.pause()
 
+    def _connect_error(self, conn, details):
+        if conn.get_driver() == "xen" and not conn.is_remote():
+            dg = vmmErrorDialog (None, 0, gtk.MESSAGE_ERROR,
+                                 gtk.BUTTONS_CLOSE,
+                                 _("Unable to open a connection to the Xen hypervisor/daemon.\n\n" +
+                                   "Verify that:\n" +
+                                   " - A Xen host kernel was booted\n" +
+                                   " - The Xen service has been started\n"),
+                                 details)
+        else:
+            dg = vmmErrorDialog (None, 0, gtk.MESSAGE_ERROR,
+                                 gtk.BUTTONS_CLOSE,
+                                 _("Unable to open a connection to the libvirt management daemon.\n\n" +
+                                   "Verify that:\n" +
+                                   " - The 'libvirtd' daemon has been started\n"),
+                                 details)
+        dg.set_title(_("Virtual Machine Manager Connection Failure"))
+        dg.run()
+        dg.hide()
+        dg.destroy()
+
+
 gobject.type_register(vmmManager)