kvm2: domain and volume XML, metadata element and NoCloud seed builders

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

internal/provider/kvm2/metadata.go

@@ -0,0 +1,78 @@
+package kvm2
+
+import (
+	"encoding/xml"
+	"strings"
+	"time"
+
+	"gitea.home.hrajfrisbee.cz/kacerr/egress-proxies-operator/internal/provider"
+)
+
+// The GC mark lives in the domain's <metadata> as one element in kvm2's own
+// namespace (spec entry 8). The namespace is what selects it in
+// DomainGetMetadata; libvirt 11.6 hands the element back without the xmlns
+// declaration, so parsing matches on the local name only.
+const (
+	metadataURI       = "https://gitea.home.hrajfrisbee.cz/kacerr/egress-proxies-operator/kvm2"
+	metadataLocalName = "instance"
+)
+
+// instanceMetadata is the mark as it is written and read back. The fields
+// are the element's text as is; managed and createdAt interpret them.
+type instanceMetadata struct {
+	XMLName   xml.Name
+	Managed   string `xml:"managed"`
+	UID       string `xml:"uid"`
+	CreatedAt string `xml:"createdAt"`
+}
+
+func newInstanceMetadata(uid string, createdAt time.Time) instanceMetadata {
+	return instanceMetadata{
+		XMLName:   xml.Name{Space: metadataURI, Local: metadataLocalName},
+		Managed:   provider.LabelManagedYes,
+		UID:       uid,
+		CreatedAt: createdAt.UTC().Format(time.RFC3339),
+	}
+}
+
+func (m instanceMetadata) managed() bool {
+	return m.Managed == provider.LabelManagedYes
+}
+
+// createdAt returns the zero time when the element carries no parsable
+// timestamp; GC treats that as old, which the spec accepts.
+func (m instanceMetadata) createdAt() time.Time {
+	t, err := time.Parse(time.RFC3339, m.CreatedAt)
+	if err != nil {
+		return time.Time{}
+	}
+	return t
+}
+
+// marshalInstanceMetadata renders the namespaced element that goes under
+// the domain's <metadata>.
+func marshalInstanceMetadata(m instanceMetadata) (string, error) {
+	m.XMLName = xml.Name{Space: metadataURI, Local: metadataLocalName}
+	out, err := xml.Marshal(m)
+	if err != nil {
+		return "", permanentf("marshalling instance metadata: %v", err)
+	}
+	return string(out), nil
+}
+
+// parseInstanceMetadata reads the element back, with or without its xmlns
+// declaration. Anything that is not an <instance> element is ErrPermanent:
+// the domain's metadata is corrupt and no retry fixes it.
+func parseInstanceMetadata(s string) (instanceMetadata, error) {
+	var m instanceMetadata
+	if strings.TrimSpace(s) == "" {
+		return instanceMetadata{}, permanentf("parsing instance metadata: empty document")
+	}
+	if err := xml.Unmarshal([]byte(s), &m); err != nil {
+		return instanceMetadata{}, permanentf("parsing instance metadata: %v", err)
+	}
+	if m.XMLName.Local != metadataLocalName {
+		return instanceMetadata{}, permanentf("parsing instance metadata: root element is <%s>, want <%s>", m.XMLName.Local, metadataLocalName)
+	}
+	return m, nil
+}