[backplane] Set Envoy node metadata

Author: dilyevsky

pkg/backplane/envoy/node.go

@@ -0,0 +1,158 @@
+package envoy
+
+import (
+	"encoding/json"
+	"fmt"
+
+	corev3 "github.com/envoyproxy/go-control-plane/envoy/config/core/v3"
+	discoveryv3 "github.com/envoyproxy/go-control-plane/envoy/service/discovery/v3"
+	"google.golang.org/protobuf/types/known/structpb"
+)
+
+// NodeMetadata represents metadata attached to an Envoy node.
+// This metadata is sent with every XDS discovery request to the control plane.
+type NodeMetadata struct {
+	// Name is the human-readable name of the node/proxy instance
+	Name string `json:"name,omitempty"`
+
+	// PrivateAddress is the private/internal address of the node
+	// This can be used for internal communication or routing
+	PrivateAddress string `json:"private_address,omitempty"`
+}
+
+// ToMap converts NodeMetadata to a map[string]interface{} for serialization
+func (nm *NodeMetadata) ToMap() (map[string]interface{}, error) {
+	// Marshal to JSON then unmarshal to map to handle all field types properly
+	data, err := json.Marshal(nm)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal node metadata: %w", err)
+	}
+
+	var result map[string]interface{}
+	if err := json.Unmarshal(data, &result); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal node metadata to map: %w", err)
+	}
+
+	// Remove empty fields
+	for k, v := range result {
+		if v == nil || v == "" {
+			delete(result, k)
+		}
+	}
+
+	return result, nil
+}
+
+// FromMap populates NodeMetadata from data.
+func (nm *NodeMetadata) FromMap(data map[string]interface{}) error {
+	if data == nil {
+		return nil
+	}
+
+	// Marshal map to JSON then unmarshal to struct
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		return fmt.Errorf("failed to marshal map data: %w", err)
+	}
+
+	if err := json.Unmarshal(jsonData, nm); err != nil {
+		return fmt.Errorf("failed to unmarshal data to node metadata: %w", err)
+	}
+
+	return nil
+}
+
+// ToStruct converts NodeMetadata to protobuf Struct for use in Envoy Node.
+func (nm *NodeMetadata) ToStruct() (*structpb.Struct, error) {
+	metadataMap, err := nm.ToMap()
+	if err != nil {
+		return nil, err
+	}
+
+	if len(metadataMap) == 0 {
+		return nil, nil
+	}
+
+	return structpb.NewStruct(metadataMap)
+}
+
+// FromStruct populates NodeMetadata from a protobuf Struct
+func (nm *NodeMetadata) FromStruct(s *structpb.Struct) error {
+	if s == nil {
+		return nil
+	}
+
+	return nm.FromMap(s.AsMap())
+}
+
+// ExtractFromDiscoveryRequest extracts NodeMetadata from an XDS DiscoveryRequest.
+func ExtractFromDiscoveryRequest(req *discoveryv3.DiscoveryRequest) (*NodeMetadata, error) {
+	if req == nil || req.Node == nil {
+		return nil, fmt.Errorf("discovery request or node is nil")
+	}
+
+	nm := &NodeMetadata{}
+
+	if req.Node.Metadata != nil {
+		if err := nm.FromStruct(req.Node.Metadata); err != nil {
+			return nil, fmt.Errorf("failed to extract metadata from discovery request: %w", err)
+		}
+	}
+
+	return nm, nil
+}
+
+// ExtractFromNode extracts NodeMetadata from an Envoy core.Node struct.
+func ExtractFromNode(node *corev3.Node) (*NodeMetadata, error) {
+	if node == nil {
+		return nil, fmt.Errorf("node is nil")
+	}
+
+	nm := &NodeMetadata{}
+
+	if node.Metadata != nil {
+		if err := nm.FromStruct(node.Metadata); err != nil {
+			return nil, fmt.Errorf("failed to extract metadata from node: %w", err)
+		}
+	}
+
+	return nm, nil
+}
+
+// String returns a string representation of the NodeMetadata.
+func (nm *NodeMetadata) String() string {
+	data, _ := json.Marshal(nm)
+	return string(data)
+}
+
+// Clone creates a deep copy of the NodeMetadata.
+func (nm *NodeMetadata) Clone() *NodeMetadata {
+	if nm == nil {
+		return nil
+	}
+
+	return &NodeMetadata{
+		Name:           nm.Name,
+		PrivateAddress: nm.PrivateAddress,
+	}
+}
+
+// IsEmpty returns true if all fields are empty.
+func (nm *NodeMetadata) IsEmpty() bool {
+	return nm.Name == "" && nm.PrivateAddress == ""
+}
+
+// Merge merges another NodeMetadata into this one.
+// Non-empty fields from other will overwrite fields in nm.
+func (nm *NodeMetadata) Merge(other *NodeMetadata) {
+	if other == nil {
+		return
+	}
+
+	if other.Name != "" {
+		nm.Name = other.Name
+	}
+	if other.PrivateAddress != "" {
+		nm.PrivateAddress = other.PrivateAddress
+	}
+}