Add custom XML serializer for instance metadata

marshal.go

@@ -4,6 +4,7 @@ package fargo
 
 import (
 	"encoding/json"
+	"encoding/xml"
 	"strconv"
 )
 
@@ -120,3 +121,26 @@ func (i *InstanceMetadata) MarshalJSON() ([]byte, error) {
 
 	return i.Raw, nil
 }
+
+// MarshalXML is a custom XML marshaler for InstanceMetadata.
+func (i InstanceMetadata) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+	tokens := []xml.Token{start}
+
+	if i.parsed != nil {
+		for key, value := range i.parsed {
+			t := xml.StartElement{Name: xml.Name{"", key}}
+			tokens = append(tokens, t, xml.CharData(value.(string)), xml.EndElement{t.Name})
+		}
+	}
+	tokens = append(tokens, xml.EndElement{start.Name})
+
+	for _, t := range tokens {
+		err := e.EncodeToken(t)
+		if err != nil {
+			return err
+		}
+	}
+
+	// flush to ensure tokens are written
+	return e.Flush()
+}