lnrpc+macaroon: skip subserver macaroons on stateless_init

This will prevent the subservers from writing macaroons to disk
when the stateless_init flag is set to true. It accomplishes
this by storing the StatelessInit value in the Macaroon Service.

lnrpc/chainrpc/chainnotifier_server.go

@@ -72,16 +72,6 @@ var (
 		"still in the process of starting")
 )
 
-// fileExists reports whether the named file or directory exists.
-func fileExists(name string) bool {
-	if _, err := os.Stat(name); err != nil {
-		if os.IsNotExist(err) {
-			return false
-		}
-	}
-	return true
-}
-
 // Server is a sub-server of the main RPC server: the chain notifier RPC. This
 // RPC sub-server allows external callers to access the full chain notifier
 // capabilities of lnd. This allows callers to create custom protocols, external
@@ -111,18 +101,20 @@ func New(cfg *Config) (*Server, lnrpc.MacaroonPerms, error) {
 	}
 
 	// Now that we know the full path of the chain notifier macaroon, we can
-	// check to see if we need to create it or not.
+	// check to see if we need to create it or not. If stateless_init is set
+	// then we don't write the macaroons.
 	macFilePath := cfg.ChainNotifierMacPath
-	if cfg.MacService != nil && !fileExists(macFilePath) {
+	if cfg.MacService != nil && !cfg.MacService.StatelessInit &&
+		!lnrpc.FileExists(macFilePath) {
+
 		log.Infof("Baking macaroons for ChainNotifier RPC Server at: %v",
 			macFilePath)
 
 		// At this point, we know that the chain notifier macaroon
 		// doesn't yet, exist, so we need to create it with the help of
 		// the main macaroon service.
 		chainNotifierMac, err := cfg.MacService.NewMacaroon(
-			context.Background(),
-			macaroons.DefaultRootKeyID,
+			context.Background(), macaroons.DefaultRootKeyID,
 			macaroonOps...,
 		)
 		if err != nil {
@@ -134,7 +126,7 @@ func New(cfg *Config) (*Server, lnrpc.MacaroonPerms, error) {
 		}
 		err = ioutil.WriteFile(macFilePath, chainNotifierMacBytes, 0644)
 		if err != nil {
-			os.Remove(macFilePath)
+			_ = os.Remove(macFilePath)
 			return nil, nil, err
 		}
 	}

lnrpc/invoicesrpc/invoices_server.go

@@ -92,8 +92,11 @@ func New(cfg *Config) (*Server, lnrpc.MacaroonPerms, error) {
 	)
 
 	// Now that we know the full path of the invoices macaroon, we can
-	// check to see if we need to create it or not.
-	if !lnrpc.FileExists(macFilePath) && cfg.MacService != nil {
+	// check to see if we need to create it or not. If stateless_init is set
+	// then we don't write the macaroons.
+	if cfg.MacService != nil && !cfg.MacService.StatelessInit &&
+		!lnrpc.FileExists(macFilePath) {
+
 		log.Infof("Baking macaroons for invoices RPC Server at: %v",
 			macFilePath)
 
@@ -113,7 +116,7 @@ func New(cfg *Config) (*Server, lnrpc.MacaroonPerms, error) {
 		}
 		err = ioutil.WriteFile(macFilePath, invoicesMacBytes, 0644)
 		if err != nil {
-			os.Remove(macFilePath)
+			_ = os.Remove(macFilePath)
 			return nil, nil, err
 		}
 	}

lnrpc/routerrpc/router_server.go

@@ -131,16 +131,6 @@ type Server struct {
 // gRPC service.
 var _ RouterServer = (*Server)(nil)
 
-// fileExists reports whether the named file or directory exists.
-func fileExists(name string) bool {
-	if _, err := os.Stat(name); err != nil {
-		if os.IsNotExist(err) {
-			return false
-		}
-	}
-	return true
-}
-
 // New creates a new instance of the RouterServer given a configuration struct
 // that contains all external dependencies. If the target macaroon exists, and
 // we're unable to create it, then an error will be returned. We also return
@@ -156,9 +146,12 @@ func New(cfg *Config) (*Server, lnrpc.MacaroonPerms, error) {
 	}
 
 	// Now that we know the full path of the router macaroon, we can check
-	// to see if we need to create it or not.
+	// to see if we need to create it or not. If stateless_init is set
+	// then we don't write the macaroons.
 	macFilePath := cfg.RouterMacPath
-	if !fileExists(macFilePath) && cfg.MacService != nil {
+	if cfg.MacService != nil && !cfg.MacService.StatelessInit &&
+		!lnrpc.FileExists(macFilePath) {
+
 		log.Infof("Making macaroons for Router RPC Server at: %v",
 			macFilePath)
 
@@ -178,7 +171,7 @@ func New(cfg *Config) (*Server, lnrpc.MacaroonPerms, error) {
 		}
 		err = ioutil.WriteFile(macFilePath, routerMacBytes, 0644)
 		if err != nil {
-			os.Remove(macFilePath)
+			_ = os.Remove(macFilePath)
 			return nil, nil, err
 		}
 	}

lnrpc/signrpc/signer_server.go

@@ -103,9 +103,12 @@ func New(cfg *Config) (*Server, lnrpc.MacaroonPerms, error) {
 	}
 
 	// Now that we know the full path of the signer macaroon, we can check
-	// to see if we need to create it or not.
+	// to see if we need to create it or not. If stateless_init is set
+	// then we don't write the macaroons.
 	macFilePath := cfg.SignerMacPath
-	if cfg.MacService != nil && !lnrpc.FileExists(macFilePath) {
+	if cfg.MacService != nil && !cfg.MacService.StatelessInit &&
+		!lnrpc.FileExists(macFilePath) {
+
 		log.Infof("Making macaroons for Signer RPC Server at: %v",
 			macFilePath)
 
@@ -125,7 +128,7 @@ func New(cfg *Config) (*Server, lnrpc.MacaroonPerms, error) {
 		}
 		err = ioutil.WriteFile(macFilePath, signerMacBytes, 0644)
 		if err != nil {
-			os.Remove(macFilePath)
+			_ = os.Remove(macFilePath)
 			return nil, nil, err
 		}
 	}

lnrpc/walletrpc/walletkit_server.go

@@ -170,18 +170,20 @@ func New(cfg *Config) (*WalletKit, lnrpc.MacaroonPerms, error) {
 	}
 
 	// Now that we know the full path of the wallet kit macaroon, we can
-	// check to see if we need to create it or not.
+	// check to see if we need to create it or not. If stateless_init is set
+	// then we don't write the macaroons.
 	macFilePath := cfg.WalletKitMacPath
-	if !lnrpc.FileExists(macFilePath) && cfg.MacService != nil {
+	if cfg.MacService != nil && !cfg.MacService.StatelessInit &&
+		!lnrpc.FileExists(macFilePath) {
+
 		log.Infof("Baking macaroons for WalletKit RPC Server at: %v",
 			macFilePath)
 
 		// At this point, we know that the wallet kit macaroon doesn't
 		// yet, exist, so we need to create it with the help of the
 		// main macaroon service.
 		walletKitMac, err := cfg.MacService.NewMacaroon(
-			context.Background(),
-			macaroons.DefaultRootKeyID,
+			context.Background(), macaroons.DefaultRootKeyID,
 			macaroonOps...,
 		)
 		if err != nil {
@@ -193,7 +195,7 @@ func New(cfg *Config) (*WalletKit, lnrpc.MacaroonPerms, error) {
 		}
 		err = ioutil.WriteFile(macFilePath, walletKitMacBytes, 0644)
 		if err != nil {
-			os.Remove(macFilePath)
+			_ = os.Remove(macFilePath)
 			return nil, nil, err
 		}
 	}