Add support for setting up <channel> elements in libvirt config

To enable use of guest agents, support for configuring the
<channel> elements in libvirt XML config is required

Blueprint: libvirt-spice
Change-Id: I3cea7b326bb2f746c5804d0aa3bbe369da6935e8
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

nova/tests/test_libvirt_config.py

@@ -539,6 +539,29 @@ class LibvirtConfigGuestConsoleTest(LibvirtConfigBaseTest):
             <console type="pty"/>""")
 
 
+class LibvirtConfigGuestChannelTest(LibvirtConfigBaseTest):
+    def test_config_spice_minimal(self):
+        obj = config.LibvirtConfigGuestChannel()
+        obj.type = "spicevmc"
+
+        xml = obj.to_xml()
+        self.assertXmlEqual(xml, """
+            <channel type="spicevmc">
+              <target type='virtio'/>
+            </channel>""")
+
+    def test_config_spice_full(self):
+        obj = config.LibvirtConfigGuestChannel()
+        obj.type = "spicevmc"
+        obj.target_name = "com.redhat.spice.0"
+
+        xml = obj.to_xml()
+        self.assertXmlEqual(xml, """
+            <channel type="spicevmc">
+              <target type='virtio' name='com.redhat.spice.0'/>
+            </channel>""")
+
+
 class LibvirtConfigGuestInterfaceTest(LibvirtConfigBaseTest):
     def test_config_ethernet(self):
         obj = config.LibvirtConfigGuestInterface()

nova/virt/libvirt/config.py

@@ -648,21 +648,34 @@ class LibvirtConfigGuestGraphics(LibvirtConfigGuestDevice):
         return dev
 
 
-class LibvirtConfigGuestChar(LibvirtConfigGuestDevice):
+class LibvirtConfigGuestCharBase(LibvirtConfigGuestDevice):
+
+    def __init__(self, **kwargs):
+        super(LibvirtConfigGuestCharBase, self).__init__(**kwargs)
+
+        self.type = "pty"
+        self.source_path = None
+
+    def format_dom(self):
+        dev = super(LibvirtConfigGuestCharBase, self).format_dom()
+
+        dev.set("type", self.type)
+        if self.type == "file":
+            dev.append(etree.Element("source", path=self.source_path))
+
+        return dev
+
+
+class LibvirtConfigGuestChar(LibvirtConfigGuestCharBase):
 
     def __init__(self, **kwargs):
         super(LibvirtConfigGuestChar, self).__init__(**kwargs)
 
-        self.type = "pty"
-        self.source_path = None
         self.target_port = None
 
     def format_dom(self):
         dev = super(LibvirtConfigGuestChar, self).format_dom()
 
-        dev.set("type", self.type)
-        if self.type == "file":
-            dev.append(etree.Element("source", path=self.source_path))
         if self.target_port is not None:
             dev.append(etree.Element("target", port=str(self.target_port)))
 
@@ -683,6 +696,26 @@ class LibvirtConfigGuestConsole(LibvirtConfigGuestChar):
                                                         **kwargs)
 
 
+class LibvirtConfigGuestChannel(LibvirtConfigGuestCharBase):
+
+    def __init__(self, **kwargs):
+        super(LibvirtConfigGuestChannel, self).__init__(root_name="channel",
+                                                        **kwargs)
+
+        self.target_type = "virtio"
+        self.target_name = None
+
+    def format_dom(self):
+        dev = super(LibvirtConfigGuestChannel, self).format_dom()
+
+        target = etree.Element("target", type=self.target_type)
+        if self.target_name is not None:
+            target.set("name", self.target_name)
+        dev.append(target)
+
+        return dev
+
+
 class LibvirtConfigGuest(LibvirtConfigObject):
 
     def __init__(self, **kwargs):