virt-xml: Add --edit --convert-to-vnc

This wires up the guest.convert_to_vnc function to command line,
and documents it.

There's one suboption `qemu-vdagent=on|off`, defaulting to `off`

Signed-off-by: Cole Robinson <crobinso@redhat.com>

man/virt-xml.rst

@@ -222,6 +222,28 @@ Sub options are:
     we add to the VM by default.
 
 
+``--convert-to-vnc``
+^^^^^^^^^^^^^^^^^^^^
+
+**Syntax:** ``--convert-to-vnc`` [OPTIONS]
+
+Convert an existing VM to exclusively use a single VNC graphics device.
+
+It will attempt to remove all references to any non-VNC graphics config, like
+Spice. For example:
+
+* ``qxl`` devices will be replaced
+* all ``spicevmc`` and ``spiceport`` devices will be removed
+* spice GL will be converted to ``egl-headless``
+
+Sub options are:
+
+``qemu-vdagent=on|off``
+    Add a ``qemu-vdagent`` device if one is not already configured.
+    This replaces some functionality of the spice vdagent.
+    This defaults to ``off`` but that could change in the future.
+
+
 XML OPTIONS
 ===========
 

tests/data/cli/compare/virt-xml-convert-to-vnc-vdagent.xml

@@ -0,0 +1,15 @@
+   <on_reboot>restart</on_reboot>
+   <on_crash>destroy</on_crash>
+   <devices>
++    <channel type="qemu-vdagent">
++      <target type="virtio" name="com.redhat.spice.0"/>
++    </channel>
++    <graphics type="vnc" port="-1"/>
++    <video>
++      <model type="vga"/>
++    </video>
+   </devices>
+ </domain>
+
+Domain 'test' defined successfully.
+Changes will take effect after the domain is fully powered off.

tests/data/cli/compare/virt-xml-convert-to-vnc.xml

@@ -0,0 +1,12 @@
+   <on_reboot>restart</on_reboot>
+   <on_crash>destroy</on_crash>
+   <devices>
++    <graphics type="vnc" port="-1"/>
++    <video>
++      <model type="vga"/>
++    </video>
+   </devices>
+ </domain>
+
+Domain 'test' defined successfully.
+Changes will take effect after the domain is fully powered off.

tests/test_cli.py

@@ -1439,6 +1439,8 @@ c.add_compare("test --add-device --network default --update --confirm --no-defin
 # --convert-* tests
 c.add_compare("--connect %(URI-KVM-X86)s --print-diff --define --edit --convert-to-q35", "convert-to-q35", input_file=(_VIRTXMLDIR + "convert-to-q35-win10-in.xml"))
 c.add_compare("--connect %(URI-KVM-X86)s --print-diff --define --edit --convert-to-q35 num_pcie_root_ports=7", "convert-to-q35-numports", input_file=(_VIRTXMLDIR + "convert-to-q35-win10-in.xml"))
+c.add_compare("--connect %(URI-KVM-X86)s test --print-diff --define --edit --convert-to-vnc", "convert-to-vnc")
+c.add_compare("--connect %(URI-KVM-X86)s test --print-diff --define --edit --convert-to-vnc qemu-vdagent=on", "convert-to-vnc-vdagent")
 
 # Regression testing for historical --add-device/--remove-device/--edit multi option handling
 # Single `--edit` with multiple options are processed in sequence

virtinst/cli.py

@@ -1678,6 +1678,28 @@ class ParserConvertToQ35(VirtCLIParser):
         self.guest.convert_to_q35(**inst.__dict__)
 
 
+############################
+# --convert-to-vnc parsing #
+############################
+
+class ParserConvertToVNC(VirtCLIParser):
+    cli_arg_name = "convert_to_vnc"
+    supports_clearxml = False
+
+    @classmethod
+    def _virtcli_class_init(cls):
+        VirtCLIParser._virtcli_class_init_common(cls)
+        cls.add_arg("qemu-vdagent", "qemu_vdagent")
+
+    def parse(self, inst):
+        class ConvertToVNCData:
+            qemu_vdagent = None
+
+        inst = ConvertToVNCData()
+        super().parse(inst)
+        self.guest.convert_to_vnc(**inst.__dict__)
+
+
 ########################
 # --unattended parsing #
 ########################

virtinst/virtxml.py

@@ -491,6 +491,12 @@ def parse_args():
         const=cli.VirtCLIParser.OPTSTR_EMPTY,
         help=_("Convert an existing VM from PC/i440FX to Q35."))
 
+    cli.ParserConvertToVNC.register()
+    conv.add_argument("--convert-to-vnc", nargs="?",
+        const=cli.VirtCLIParser.OPTSTR_EMPTY,
+        help=_("Convert an existing VM to use VNC graphics. "
+               "This removes any remnants of Spice graphics."))
+
     g = parser.add_argument_group(_("XML options"))
     cli.add_disk_option(g, editexample=True)
     cli.add_net_option(g)