refactor: centralize SSH executable creation

Signed-off-by: Bartek Mucha <muchzill4@gmail.com>

Author: muchzill4

cmd/limactl/copy.go

@@ -84,7 +84,11 @@ func copyAction(cmd *cobra.Command, args []string) error {
 		scpFlags = append(scpFlags, "-r")
 	}
 	// this assumes that ssh and scp come from the same place, but scp has no -V
-	legacySSH := sshutil.DetectOpenSSHVersion(sshutil.SSHExe{Executable: "ssh"}).LessThan(*semver.New("8.0.0"))
+	sshExe, err := sshutil.NewSSHExe()
+	if err != nil {
+		return err
+	}
+	legacySSH := sshutil.DetectOpenSSHVersion(sshExe).LessThan(*semver.New("8.0.0"))
 	for _, arg := range args {
 		if runtime.GOOS == "windows" {
 			if filepath.IsAbs(arg) {
@@ -135,14 +139,22 @@ func copyAction(cmd *cobra.Command, args []string) error {
 		// arguments such as ControlPath.  This is preferred as we can multiplex
 		// sessions without re-authenticating (MaxSessions permitting).
 		for _, inst := range instances {
-			sshOpts, err = sshutil.SSHOpts(sshutil.SSHExe{Executable: "ssh"}, inst.Dir, *inst.Config.User.Name, false, false, false, false)
+			sshExe, err := sshutil.NewSSHExe()
+			if err != nil {
+				return err
+			}
+			sshOpts, err = sshutil.SSHOpts(sshExe, inst.Dir, *inst.Config.User.Name, false, false, false, false)
 			if err != nil {
 				return err
 			}
 		}
 	} else {
 		// Copying among multiple hosts; we can't pass in host-specific options.
-		sshOpts, err = sshutil.CommonOpts(sshutil.SSHExe{Executable: "ssh"}, false)
+		sshExe, err := sshutil.NewSSHExe()
+		if err != nil {
+			return err
+		}
+		sshOpts, err = sshutil.CommonOpts(sshExe, false)
 		if err != nil {
 			return err
 		}

cmd/limactl/shell.go

@@ -196,7 +196,7 @@ func shellAction(cmd *cobra.Command, args []string) error {
 		)
 	}
 
-	sshExe, err := sshutil.SSHArguments()
+	sshExe, err := sshutil.NewSSHExe()
 	if err != nil {
 		return err
 	}
@@ -236,7 +236,7 @@ func shellAction(cmd *cobra.Command, args []string) error {
 		script,
 	}...)
 	allArgs := append(sshExe.Args, sshArgs...)
-	sshCmd := exec.Command(sshExe.Executable, allArgs...)
+	sshCmd := exec.Command(sshExe.Exe, allArgs...)
 	sshCmd.Stdin = os.Stdin
 	sshCmd.Stdout = os.Stdout
 	sshCmd.Stderr = os.Stderr

cmd/limactl/show-ssh.go

@@ -92,8 +92,12 @@ func showSSHAction(cmd *cobra.Command, args []string) error {
 	}
 	logrus.Warnf("`limactl show-ssh` is deprecated. Instead, use `ssh -F %s %s`.",
 		filepath.Join(inst.Dir, filenames.SSHConfig), inst.Hostname)
+	sshExe, err := sshutil.NewSSHExe()
+	if err != nil {
+		return err
+	}
 	opts, err := sshutil.SSHOpts(
-		sshutil.SSHExe{Executable: "ssh"},
+		sshExe,
 		inst.Dir,
 		*inst.Config.User.Name,
 		*inst.Config.SSH.LoadDotSSHPubKeys,

cmd/limactl/tunnel.go

@@ -82,7 +82,7 @@ func tunnelAction(cmd *cobra.Command, args []string) error {
 		}
 	}
 
-	sshExe, err := sshutil.SSHArguments()
+	sshExe, err := sshutil.NewSSHExe()
 	if err != nil {
 		return err
 	}
@@ -108,7 +108,7 @@ func tunnelAction(cmd *cobra.Command, args []string) error {
 		inst.SSHAddress,
 	}...)
 	allArgs := append(sshExe.Args, sshArgs...)
-	sshCmd := exec.Command(sshExe.Executable, allArgs...)
+	sshCmd := exec.Command(sshExe.Exe, allArgs...)
 	sshCmd.Stdout = stderr
 	sshCmd.Stderr = stderr
 	logrus.Debugf("executing ssh (may take a long)): %+v", sshCmd.Args)

pkg/hostagent/hostagent.go

@@ -146,8 +146,12 @@ func New(instName string, stdout io.Writer, signalCh chan os.Signal, opts ...Opt
 		return nil, err
 	}
 
+	sshExe, err := sshutil.NewSSHExe()
+	if err != nil {
+		return nil, err
+	}
 	sshOpts, err := sshutil.SSHOpts(
-		sshutil.SSHExe{Executable: "ssh"},
+		sshExe,
 		inst.Dir,
 		*inst.Config.User.Name,
 		*inst.Config.SSH.LoadDotSSHPubKeys,

pkg/sshutil/sshutil.go

@@ -36,11 +36,11 @@ import (
 const EnvShellSSH = "SSH"
 
 type SSHExe struct {
-	Executable string
-	Args       []string
+	Exe  string
+	Args []string
 }
 
-func SSHArguments() (SSHExe, error) {
+func NewSSHExe() (SSHExe, error) {
 	var sshExe SSHExe
 
 	if sshShell := os.Getenv(EnvShellSSH); sshShell != "" {
@@ -50,7 +50,7 @@ func SSHArguments() (SSHExe, error) {
 			logrus.WithError(err).Warnf("Failed to split %s variable into shell tokens. "+
 				"Falling back to 'ssh' command", EnvShellSSH)
 		case len(sshShellFields) > 0:
-			sshExe.Executable = sshShellFields[0]
+			sshExe.Exe = sshShellFields[0]
 			if len(sshShellFields) > 1 {
 				sshExe.Args = sshShellFields[1:]
 			}
@@ -62,7 +62,7 @@ func SSHArguments() (SSHExe, error) {
 	if err != nil {
 		return SSHExe{}, err
 	}
-	sshExe.Executable = executable
+	sshExe.Exe = executable
 
 	return sshExe, nil
 }
@@ -376,7 +376,7 @@ func detectOpenSSHInfo(sshExe SSHExe) openSSHInfo {
 	)
 	// TODO: Fix this function to properly handle complex SSH commands like "kitten ssh"
 	// The current LookPath, os.Stat, and caching logic doesn't work well for multi-word commands
-	path, err := exec.LookPath(sshExe.Executable)
+	path, err := exec.LookPath(sshExe.Exe)
 	if err != nil {
 		logrus.Warnf("failed to find ssh executable: %v", err)
 	} else {
@@ -391,7 +391,7 @@ func detectOpenSSHInfo(sshExe SSHExe) openSSHInfo {
 	}
 	// -V should be last
 	allArgs := append(sshExe.Args, "-o", "GSSAPIAuthentication=no", "-V")
-	cmd := exec.Command(sshExe.Executable, allArgs...)
+	cmd := exec.Command(sshExe.Exe, allArgs...)
 	cmd.Stderr = &stderr
 	if err := cmd.Run(); err != nil {
 		logrus.Warnf("failed to run %v: stderr=%q", cmd.Args, stderr.String())