Add support for libvirt domaincapabilities

Author: PhilippMatthes

internal/libvirt/domcapabilities/client.go

@@ -0,0 +1,129 @@
+/*
+SPDX-FileCopyrightText: Copyright 2025 SAP SE or an SAP affiliate company and cobaltcore-dev contributors
+SPDX-License-Identifier: Apache-2.0
+
+Licensed under the Apache License, LibVirtVersion 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package domcapabilities
+
+import (
+	"encoding/xml"
+	"fmt"
+
+	v1 "github.com/cobaltcore-dev/openstack-hypervisor-operator/api/v1"
+	libvirt "github.com/digitalocean/go-libvirt"
+	"sigs.k8s.io/controller-runtime/pkg/log"
+)
+
+// Client that returns the domain capabilities of the host we are mounted on.
+type Client interface {
+	// Return the capabilities status of the host we are mounted on.
+	Get(virt *libvirt.Libvirt) (v1.DomainCapabilities, error)
+}
+
+// Implementation of the Client interface.
+type client struct{}
+
+// Create a new domain capabilities client.
+func NewClient() Client {
+	return &client{}
+}
+
+// Return the domain capabilities of the host we are mounted on.
+func (m *client) Get(virt *libvirt.Libvirt) (v1.DomainCapabilities, error) {
+	capabilitiesXMLBytes, err := virt.Capabilities()
+	if err != nil {
+		log.Log.Error(err, "failed to get libvirt capabilities")
+		return v1.DomainCapabilities{}, err
+	}
+	var capabilities DomainCapabilities
+	if err := xml.Unmarshal(capabilitiesXMLBytes, &capabilities); err != nil {
+		log.Log.Error(err, "failed to unmarshal libvirt capabilities")
+		return v1.DomainCapabilities{}, err
+	}
+	return convert(capabilities)
+}
+
+// Emulated domain capabilities client returning an embedded capabilities xml.
+type clientEmulator struct{}
+
+// Create a new emulated domain capabilities client.
+func NewClientEmulator() Client {
+	return &clientEmulator{}
+}
+
+// Get the domain capabilities of the host we are mounted on.
+func (c *clientEmulator) Get(virt *libvirt.Libvirt) (v1.DomainCapabilities, error) {
+	var capabilities DomainCapabilities
+	if err := xml.Unmarshal(exampleXML, &capabilities); err != nil {
+		log.Log.Error(err, "failed to unmarshal example capabilities")
+		return v1.DomainCapabilities{}, err
+	}
+	return convert(capabilities)
+}
+
+// Convert the libvirt capabilities to the API format.
+func convert(in DomainCapabilities) (out v1.DomainCapabilities, err error) {
+	out.Arch = in.Arch
+	out.HypervisorType = in.Domain
+
+	// Convert the supported cpu modes into a flat list of supported cpu types.
+	// - <mode name="example" supported="yes"><enum name="1"/></mode> becomes
+	// "mode/example" and "mode/example/1"
+	// - <mode name="example2" supported="no"><enum name="1"/></mode> is ignored
+	// - <mode name="example3" supported="yes"></mode> becomes "mode/example3"
+	out.SupportedCpuModes = []string{}
+	for _, cpuMode := range in.CPU.Modes {
+		if cpuMode.Supported != "yes" {
+			continue
+		}
+		out.SupportedCpuModes = append(out.SupportedCpuModes,
+			fmt.Sprintf("mode/%s", cpuMode.Name))
+		for _, enum := range cpuMode.Enums {
+			for _, cpuType := range enum.Values {
+				out.SupportedCpuModes = append(out.SupportedCpuModes,
+					fmt.Sprintf("mode/%s/%s", cpuMode.Name, cpuType))
+			}
+		}
+	}
+
+	// Convert the supported devices into a flat list.
+	// - <video supported="yes"><enum name="v1"/></video>
+	// becomes "video" and "video/v1"
+	// - <video supported="no"><enum name="v2"/></video> is ignored
+	// - <video supported="yes"></video> becomes "video".
+	out.SupportedDevices = []string{}
+	for _, device := range in.Devices.Devices {
+		if device.Supported != "yes" {
+			continue
+		}
+		out.SupportedDevices = append(out.SupportedDevices, device.XMLName.Local)
+		for _, enum := range device.Enums {
+			for _, deviceType := range enum.Values {
+				out.SupportedDevices = append(out.SupportedDevices,
+					fmt.Sprintf("%s/%s", device.XMLName.Local, deviceType))
+			}
+		}
+	}
+
+	// Convert the supported features into a flat list.
+	out.SupportedFeatures = []string{}
+	for _, feature := range in.Features.Features {
+		if feature.Supported == "yes" {
+			out.SupportedFeatures = append(out.SupportedFeatures, feature.XMLName.Local)
+		}
+	}
+
+	return out, nil
+}