Feature: OPENVPN_VERSION which can be 2.4 or 2.5

internal/openvpn/command.go

@@ -9,16 +9,42 @@ import (
 	"github.com/qdm12/gluetun/internal/constants"
 )
 
-func (c *configurator) Start(ctx context.Context) (
+var ErrVersionUnknown = errors.New("OpenVPN version is unknown")
+
+const (
+	binOpenvpn24 = "openvpn2.4"
+	binOpenvpn25 = "openvpn"
+)
+
+func (c *configurator) Start(ctx context.Context, version string) (
 	stdoutLines, stderrLines chan string, waitError chan error, err error) {
-	c.logger.Info("starting openvpn")
-	return c.commander.Start(ctx, "openvpn", "--config", constants.OpenVPNConf)
+	var bin string
+	switch version {
+	case constants.Openvpn24:
+		bin = binOpenvpn24
+	case constants.Openvpn25:
+		bin = binOpenvpn25
+	default:
+		return nil, nil, nil, fmt.Errorf("%w: %s", ErrVersionUnknown, version)
+	}
+
+	c.logger.Info("starting OpenVPN " + version)
+
+	return c.commander.Start(ctx, bin, "--config", constants.OpenVPNConf)
+}
+
+func (c *configurator) Version24(ctx context.Context) (version string, err error) {
+	return c.version(ctx, binOpenvpn24)
+}
+
+func (c *configurator) Version25(ctx context.Context) (version string, err error) {
+	return c.version(ctx, binOpenvpn25)
 }
 
 var ErrVersionTooShort = errors.New("version output is too short")
 
-func (c *configurator) Version(ctx context.Context) (string, error) {
-	output, err := c.commander.Run(ctx, "openvpn", "--version")
+func (c *configurator) version(ctx context.Context, binName string) (version string, err error) {
+	output, err := c.commander.Run(ctx, binName, "--version")
 	if err != nil && err.Error() != "exit status 1" {
 		return "", err
 	}