fix: allow Literal IP addresses in topo setup-keys

cmd/topo/setup_keys.go

@@ -33,6 +33,12 @@ var setupKeysCmd = &cobra.Command{
 		}
 
 		dest := ssh.NewDestination(targetArg)
+		user, err := ssh.IsDestinationAlreadyConfiguredWithAnotherUser(dest)
+		if err != nil {
+			return fmt.Errorf("%w; note: a per user SSH config entry should be created when setting up keys", err)
+		}
+
+		dest.User = user
 		targetSlug := dest.Slugify()
 		if privateKeyPath == "" {
 			privateKeyPath, err = setupkeys.GetDefaultPrivateKeyPath(targetSlug)
@@ -46,11 +52,6 @@ var setupKeysCmd = &cobra.Command{
 			return err
 		}
 
-		err = ssh.IsDestinationAlreadyConfiguredWithAnotherUser(dest)
-		if err != nil {
-			return fmt.Errorf("%w; note: a per user SSH config entry should be created when setting up keys", err)
-		}
-
 		seq, err := setupkeys.NewKeySetup(dest, privateKeyPath, parsedKeyType)
 		if err != nil {
 			return err
@@ -64,6 +65,7 @@ var setupKeysCmd = &cobra.Command{
 		modifiers := []ssh.ConfigDirectiveModifier{
 			ssh.NewEnsureConfigDirectivePath("IdentityFile", privateKeyPath),
 			ssh.NewEnsureConfigDirective("IdentitiesOnly", "yes"),
+			ssh.NewEnsureConfigDirective("User", dest.User),
 		}
 
 		return ssh.CreateOrModifyConfigFile(dest, modifiers)

internal/ssh/config.go

@@ -41,31 +41,35 @@ func NewConfigFromBytes(data []byte) Config {
 	return config
 }
 
-func IsDestinationAlreadyConfiguredWithAnotherUser(dest Destination) error {
-	hostConfig, err := LookupExplicitHostConfig(dest.Host, dest.Port)
+// IsDestinationAlreadyConfiguredWithAnotherUser checks if the destination is already configured with another user.
+// If it is, an error is returned. Otherwise, the user associated with the destination in the SSH config is returned.
+func IsDestinationAlreadyConfiguredWithAnotherUser(dest Destination) (string, error) {
+	output, err := readConfig(Destination{Host: dest.Host, Port: dest.Port})
 	if err != nil {
-		return err
+		return "", err
 	}
 
-	if dest.User != "" && hostConfig.User != dest.User {
-		return fmt.Errorf("ssh host/alias %q is already associated with user %q", dest.Host, hostConfig.User)
-	}
-	return nil
-}
-
-// LookupExplicitHostConfig returns configuration, only if there's an explicit entry for the given host/port
-func LookupExplicitHostConfig(host, port string) (Config, error) {
-	dest := Destination{Host: host, Port: port}
-	output, err := readConfig(dest)
-	if err != nil {
-		return Config{}, err
-	}
+	hostConfig := NewConfigFromBytes(output)
+	isExplicitHostConfig := IsExplicitHostConfig(dest.Host, output)
 
-	if !IsExplicitHostConfig(host, output) {
-		return Config{}, fmt.Errorf("no explicit host config found for %s", host)
+	if isExplicitHostConfig {
+		if dest.User != "" && hostConfig.User != dest.User {
+			return "", fmt.Errorf(
+				"ssh host/alias %q is already associated with user %q",
+				dest.Host,
+				hostConfig.User,
+			)
+		}
+	} else if !isExplicitHostConfig && !dest.IsIPLiteral() {
+		return "", fmt.Errorf("no explicit host config found for %s", dest.Host)
+	} else if !isExplicitHostConfig && dest.IsIPLiteral() {
+		if dest.User != "" {
+			return dest.User, nil
+		}
+		return hostConfig.User, nil
 	}
 
-	return NewConfigFromBytes(output), nil
+	return hostConfig.User, nil
 }
 
 func IsExplicitHostConfig(host string, config []byte) bool {

internal/ssh/destination.go

@@ -46,6 +46,10 @@ func (d Destination) IsLocalhost() bool {
 	return strings.EqualFold(d.Host, "localhost") || d.Host == "127.0.0.1"
 }
 
+func (d Destination) IsIPLiteral() bool {
+	return net.ParseIP(d.Host) != nil
+}
+
 func (d Destination) AsURI() string {
 	return d.String()
 }

internal/ssh/destination_test.go

@@ -200,6 +200,12 @@ func TestDestination(t *testing.T) {
 		})
 	})
 
+	t.Run("IsIPLiteral", func(t *testing.T) {
+		assert.True(t, ssh.Destination{User: "root", Host: "10.1.197.67", Port: "22"}.IsIPLiteral())
+		assert.True(t, ssh.Destination{User: "darth", Host: "2001:db8::1", Port: "80"}.IsIPLiteral())
+		assert.False(t, ssh.Destination{User: "vader", Host: "board", Port: "300"}.IsIPLiteral())
+	})
+
 	t.Run("Slugify", func(t *testing.T) {
 		t.Run("slugifies the uri", func(t *testing.T) {
 			d := ssh.Destination{