CNS to Unix domain socket capability

Author: pjohnst5

cns/configuration/configuration.go

@@ -112,9 +112,10 @@ type KeyVaultSettings struct {
 }
 
 type GRPCSettings struct {
-	Enable    bool
-	IPAddress string
-	Port      uint16
+	Enable           bool
+	IPAddress        string
+	Port             uint16
+	DomainSocketPath string
 }
 
 func getConfigFilePath(cmdPath string) (string, error) {

cns/grpc/server.go

@@ -22,8 +22,9 @@ type Server struct {
 
 // GrpcServerSettings holds the gRPC server settings.
 type ServerSettings struct {
-	IPAddress string
-	Port      uint16
+	IPAddress        string
+	Port             uint16
+	DomainSocketPath string
 }
 
 // NewServer initializes a new gRPC server instance.
@@ -43,24 +44,46 @@ func NewServer(settings ServerSettings, cnsService pb.CNSServer, logger *zap.Log
 }
 
 // Start starts the gRPC server.
+// Now this has the capability of listening over both TCP and Unix Domain Sockets.
+// If both IPAddress and DomainSocketPath are provided, it will prioritize TCP.
 func (s *Server) Start() error {
-	address := net.JoinHostPort(s.Settings.IPAddress, strconv.FormatUint(uint64(s.Settings.Port), 10))
-	lis, err := net.Listen("tcp", address)
-	if err != nil {
-		log.Printf("[Listener] Failed to listen on gRPC endpoint: %+v", err)
-		return fmt.Errorf("failed to listen on address %s: %w", address, err)
-	}
-	log.Printf("[Listener] Started listening on gRPC endpoint %s.", address)
+	if s.Settings.IPAddress != "" || s.Settings.Port != 0 {
+		address := net.JoinHostPort(s.Settings.IPAddress, strconv.FormatUint(uint64(s.Settings.Port), 10))
+		lis, err := net.Listen("tcp", address)
+		if err != nil {
+			log.Printf("[Listener] Failed to listen on gRPC endpoint: %+v", err)
+			return fmt.Errorf("failed to listen on address %s: %w", address, err)
+		}
+		log.Printf("[Listener] Started listening on gRPC endpoint %s.", address)
 
-	grpcServer := grpc.NewServer()
-	pb.RegisterCNSServer(grpcServer, s.CnsService)
+		grpcServer := grpc.NewServer()
+		pb.RegisterCNSServer(grpcServer, s.CnsService)
 
-	// Register reflection service on gRPC server.
-	reflection.Register(grpcServer)
+		// Register reflection service on gRPC server.
+		reflection.Register(grpcServer)
 
-	if err := grpcServer.Serve(lis); err != nil {
-		return fmt.Errorf("failed to serve gRPC server: %w", err)
-	}
+		if err := grpcServer.Serve(lis); err != nil {
+			return fmt.Errorf("failed to serve gRPC server: %w", err)
+		}
+	} else if s.Settings.DomainSocketPath != "" {
+		lis, err := net.Listen("unix", s.Settings.DomainSocketPath)
+		if err != nil {
+			log.Printf("[Listener] Failed to listen on gRPC Unix Domain Socket: %+v", err)
+			return fmt.Errorf("failed to listen on Unix Domain Socket %s: %w", s.Settings.DomainSocketPath, err)
+		}
+		log.Printf("[Listener] Started listening on gRPC Unix Domain Socket %s.", s.Settings.DomainSocketPath)
+
+		grpcServer := grpc.NewServer()
+		pb.RegisterCNSServer(grpcServer, s.CnsService)
 
+		// Register reflection service on gRPC server.
+		reflection.Register(grpcServer)
+
+		if err := grpcServer.Serve(lis); err != nil {
+			return fmt.Errorf("failed to serve gRPC server: %w", err)
+		}
+	} else {
+		return fmt.Errorf("no valid gRPC server settings provided: IP address or domain socket path must be specified")
+	}
 	return nil
 }

cns/service/main.go

@@ -974,8 +974,9 @@ func main() {
 	if cnsconfig.GRPCSettings.Enable {
 		// Define gRPC server settings
 		settings := grpc.ServerSettings{
-			IPAddress: cnsconfig.GRPCSettings.IPAddress,
-			Port:      cnsconfig.GRPCSettings.Port,
+			IPAddress:        cnsconfig.GRPCSettings.IPAddress,
+			Port:             cnsconfig.GRPCSettings.Port,
+			DomainSocketPath: cnsconfig.GRPCSettings.DomainSocketPath,
 		}
 
 		// Initialize CNS service