Maint: move OpenVPN configurator to openvpn/config

internal/openvpn/config/command.go

@@ -0,0 +1,76 @@
+package config
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os/exec"
+	"strings"
+	"syscall"
+
+	"github.com/qdm12/gluetun/internal/constants"
+)
+
+var ErrVersionUnknown = errors.New("OpenVPN version is unknown")
+
+const (
+	binOpenvpn24 = "openvpn2.4"
+	binOpenvpn25 = "openvpn"
+)
+
+type Starter interface {
+	Start(ctx context.Context, version string, flags []string) (
+		stdoutLines, stderrLines chan string, waitError chan error, err error)
+}
+
+func (c *configurator) Start(ctx context.Context, version string, flags []string) (
+	stdoutLines, stderrLines chan string, waitError chan error, err error) {
+	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)
+
+	args := []string{"--config", constants.OpenVPNConf}
+	args = append(args, flags...)
+	cmd := exec.CommandContext(ctx, bin, args...)
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+
+	return c.cmder.Start(cmd)
+}
+
+type VersionGetter interface {
+	Version24(ctx context.Context) (version string, err error)
+	Version25(ctx context.Context) (version string, err error)
+}
+
+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, binName string) (version string, err error) {
+	cmd := exec.CommandContext(ctx, binName, "--version")
+	output, err := c.cmder.Run(cmd)
+	if err != nil && err.Error() != "exit status 1" {
+		return "", err
+	}
+	firstLine := strings.Split(output, "\n")[0]
+	words := strings.Fields(firstLine)
+	const minWords = 2
+	if len(words) < minWords {
+		return "", fmt.Errorf("%w: %s", ErrVersionTooShort, firstLine)
+	}
+	return words[1], nil
+}