[misc]: Factorize SetFlagsFromEnvVars and add support for CREDENTIALS_DIRECTORY

The code for setting up command flags values from environment variables
was copied in three different places, this puts the helper function in
the util package so that every component can use it.
Furthermore, it now supports reading values from files in
`$CREDENTIALS_DIRECTORY`, which allows direct integration with systemd's
`LoadCredential` mechanism (but any platform can define such a variable
and pass values as files).

Author: Tom-Hubrecht

client/cmd/down.go

@@ -16,7 +16,7 @@ var downCmd = &cobra.Command{
 	Use:   "down",
 	Short: "down netbird connections",
 	RunE: func(cmd *cobra.Command, args []string) error {
-		SetFlagsFromEnvVars(rootCmd)
+		util.SetFlagsFromEnvVars(rootCmd)
 
 		cmd.SetOut(cmd.OutOrStdout())
 

client/cmd/login.go

@@ -371,7 +371,7 @@ func isUnixRunningDesktop() bool {
 }
 
 func setEnvAndFlags(cmd *cobra.Command) error {
-	SetFlagsFromEnvVars(rootCmd)
+	util.SetFlagsFromEnvVars(rootCmd)
 
 	cmd.SetOut(cmd.OutOrStdout())
 

client/cmd/logout.go

@@ -9,13 +9,14 @@ import (
 	"github.com/spf13/cobra"
 
 	"github.com/netbirdio/netbird/client/proto"
+	"github.com/netbirdio/netbird/util"
 )
 
 var logoutCmd = &cobra.Command{
 	Use:   "logout",
 	Short: "logout from the Netbird Management Service and delete peer",
 	RunE: func(cmd *cobra.Command, args []string) error {
-		SetFlagsFromEnvVars(rootCmd)
+		util.SetFlagsFromEnvVars(rootCmd)
 
 		cmd.SetOut(cmd.OutOrStdout())
 

client/cmd/profile.go

@@ -53,8 +53,8 @@ var profileSelectCmd = &cobra.Command{
 }
 
 func setupCmd(cmd *cobra.Command) error {
-	SetFlagsFromEnvVars(rootCmd)
-	SetFlagsFromEnvVars(cmd)
+	util.SetFlagsFromEnvVars(rootCmd)
+	util.SetFlagsFromEnvVars(cmd)
 
 	cmd.SetOut(cmd.OutOrStdout())
 

client/cmd/root.go

@@ -18,11 +18,11 @@ import (
 	"github.com/cenkalti/backoff/v4"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
-	"github.com/spf13/pflag"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials/insecure"
 
 	"github.com/netbirdio/netbird/client/internal/profilemanager"
+	"github.com/netbirdio/netbird/util"
 )
 
 const (
@@ -194,38 +194,6 @@ func SetupCloseHandler(ctx context.Context, cancel context.CancelFunc) {
 	}()
 }
 
-// SetFlagsFromEnvVars reads and updates flag values from environment variables with prefix WT_
-func SetFlagsFromEnvVars(cmd *cobra.Command) {
-	flags := cmd.PersistentFlags()
-	flags.VisitAll(func(f *pflag.Flag) {
-		oldEnvVar := FlagNameToEnvVar(f.Name, "WT_")
-
-		if value, present := os.LookupEnv(oldEnvVar); present {
-			err := flags.Set(f.Name, value)
-			if err != nil {
-				log.Infof("unable to configure flag %s using variable %s, err: %v", f.Name, oldEnvVar, err)
-			}
-		}
-
-		newEnvVar := FlagNameToEnvVar(f.Name, "NB_")
-
-		if value, present := os.LookupEnv(newEnvVar); present {
-			err := flags.Set(f.Name, value)
-			if err != nil {
-				log.Infof("unable to configure flag %s using variable %s, err: %v", f.Name, newEnvVar, err)
-			}
-		}
-	})
-}
-
-// FlagNameToEnvVar converts flag name to environment var name adding a prefix,
-// replacing dashes and making all uppercase (e.g. setup-keys is converted to NB_SETUP_KEYS according to the input prefix)
-func FlagNameToEnvVar(cmdFlag string, prefix string) string {
-	parsed := strings.ReplaceAll(cmdFlag, "-", "_")
-	upper := strings.ToUpper(parsed)
-	return prefix + upper
-}
-
 // DialClientGRPCServer returns client connection to the daemon server.
 func DialClientGRPCServer(ctx context.Context, addr string) (*grpc.ClientConn, error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Second*3)
@@ -382,7 +350,7 @@ func migrateToNetbird(oldPath, newPath string) bool {
 }
 
 func getClient(cmd *cobra.Command) (*grpc.ClientConn, error) {
-	SetFlagsFromEnvVars(rootCmd)
+	util.SetFlagsFromEnvVars(rootCmd)
 	cmd.SetOut(cmd.OutOrStdout())
 
 	conn, err := DialClientGRPCServer(cmd.Context(), daemonAddr)

client/cmd/root_test.go

@@ -8,6 +8,7 @@ import (
 	"github.com/spf13/cobra"
 
 	"github.com/netbirdio/netbird/client/iface"
+	"github.com/netbirdio/netbird/util"
 )
 
 func TestInitCommands(t *testing.T) {
@@ -45,7 +46,7 @@ func TestSetFlagsFromEnvVars(t *testing.T) {
 		Long:         "test",
 		SilenceUsage: true,
 		Run: func(cmd *cobra.Command, args []string) {
-			SetFlagsFromEnvVars(cmd)
+			util.SetFlagsFromEnvVars(cmd)
 		},
 	}
 

client/cmd/service_controller.go

@@ -103,8 +103,8 @@ func (p *program) Stop(srv service.Service) error {
 
 // Common setup for service control commands
 func setupServiceControlCommand(cmd *cobra.Command, ctx context.Context, cancel context.CancelFunc) (service.Service, error) {
-	SetFlagsFromEnvVars(rootCmd)
-	SetFlagsFromEnvVars(serviceCmd)
+	util.SetFlagsFromEnvVars(rootCmd)
+	util.SetFlagsFromEnvVars(serviceCmd)
 
 	cmd.SetOut(cmd.OutOrStdout())
 

client/cmd/service_installer.go

@@ -20,8 +20,8 @@ var ErrGetServiceStatus = fmt.Errorf("failed to get service status")
 
 // Common service command setup
 func setupServiceCommand(cmd *cobra.Command) error {
-	SetFlagsFromEnvVars(rootCmd)
-	SetFlagsFromEnvVars(serviceCmd)
+	util.SetFlagsFromEnvVars(rootCmd)
+	util.SetFlagsFromEnvVars(serviceCmd)
 	cmd.SetOut(cmd.OutOrStdout())
 	return handleRebrand(cmd)
 }

client/cmd/ssh.go

@@ -42,8 +42,8 @@ var sshCmd = &cobra.Command{
 	},
 	Short: "connect to a remote SSH server",
 	RunE: func(cmd *cobra.Command, args []string) error {
-		SetFlagsFromEnvVars(rootCmd)
-		SetFlagsFromEnvVars(cmd)
+		util.SetFlagsFromEnvVars(rootCmd)
+		util.SetFlagsFromEnvVars(cmd)
 
 		cmd.SetOut(cmd.OutOrStdout())
 

client/cmd/status.go

@@ -51,7 +51,7 @@ func init() {
 }
 
 func statusFunc(cmd *cobra.Command, args []string) error {
-	SetFlagsFromEnvVars(rootCmd)
+	util.SetFlagsFromEnvVars(rootCmd)
 
 	cmd.SetOut(cmd.OutOrStdout())