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.GetUserFromConfig(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)
+func GetUserFromConfig(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
+	return ResolveConfiguredUser(dest, output)
 }
 
-// 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
-	}
+func ResolveConfiguredUser(dest Destination, configOutput []byte) (string, error) {
+	hostConfig := NewConfigFromBytes(configOutput)
 
-	if !IsExplicitHostConfig(host, output) {
-		return Config{}, fmt.Errorf("no explicit host config found for %s", host)
+	if IsExplicitHostConfig(dest.Host, configOutput) {
+		if hostConfig.User != "" && dest.User != "" && hostConfig.User != dest.User {
+			return "", fmt.Errorf(
+				"ssh host/alias %q is already associated with user %q",
+				dest.Host,
+				hostConfig.User,
+			)
+		}
+		if dest.User != "" {
+			return dest.User, nil
+		}
+		return hostConfig.User, nil
 	}
 
-	return NewConfigFromBytes(output), nil
+	if dest.User != "" {
+		return dest.User, nil
+	}
+	return hostConfig.User, nil
 }
 
 func IsExplicitHostConfig(host string, config []byte) bool {

internal/ssh/config_test.go

@@ -56,6 +56,80 @@ user homer
 	})
 }
 
+func TestResolveConfiguredUser(t *testing.T) {
+	t.Run("with explicit configuration", func(t *testing.T) {
+		explicitConfig := []byte(`debug1: /tmp/.ssh/topo_config line 1: Applying options for board-alias
+debug1: /etc/ssh/ssh_config line 57: Applying options for *
+user root
+hostname 10.2.2.26
+`)
+
+		t.Run("returns destination's user when no user is configured", func(t *testing.T) {
+			config := []byte(`debug1: /tmp/.ssh/topo_config line 1: Applying options for board-alias
+debug1: /etc/ssh/ssh_config line 57: Applying options for *
+hostname 10.2.2.26
+`)
+			dest := ssh.Destination{User: "root", Host: "board-alias"}
+
+			got, err := ssh.ResolveConfiguredUser(dest, config)
+
+			assert.NoError(t, err)
+			assert.Equal(t, "root", got)
+		})
+
+		t.Run("returns destination's user when user is configured as the same user", func(t *testing.T) {
+			dest := ssh.Destination{User: "root", Host: "board-alias"}
+
+			got, err := ssh.ResolveConfiguredUser(dest, explicitConfig)
+
+			assert.NoError(t, err)
+			assert.Equal(t, "root", got)
+		})
+
+		t.Run("returns configured user when destination's user is not set", func(t *testing.T) {
+			dest := ssh.Destination{Host: "board-alias"}
+
+			got, err := ssh.ResolveConfiguredUser(dest, explicitConfig)
+
+			assert.NoError(t, err)
+			assert.Equal(t, "root", got)
+		})
+
+		t.Run("errors if destination's user doesn't match configured user", func(t *testing.T) {
+			dest := ssh.Destination{User: "admin", Host: "board-alias"}
+
+			_, err := ssh.ResolveConfiguredUser(dest, explicitConfig)
+
+			assert.ErrorContains(t, err, `ssh host/alias "board-alias" is already associated with user "root"`)
+		})
+	})
+
+	t.Run("without explicit host configuration", func(t *testing.T) {
+		wildcardConfig := []byte(`debug1: /etc/ssh/ssh_config line 57: Applying options for *
+user username
+hostname board-alias
+`)
+
+		t.Run("returns destination's user when it's set", func(t *testing.T) {
+			dest := ssh.Destination{User: "root", Host: "board-alias"}
+
+			got, err := ssh.ResolveConfiguredUser(dest, wildcardConfig)
+
+			assert.NoError(t, err)
+			assert.Equal(t, "root", got)
+		})
+
+		t.Run("returns configured user when destination's user is not set", func(t *testing.T) {
+			dest := ssh.Destination{Host: "board-alias"}
+
+			got, err := ssh.ResolveConfiguredUser(dest, wildcardConfig)
+
+			assert.NoError(t, err)
+			assert.Equal(t, "username", got)
+		})
+	})
+}
+
 func TestIsExplicitHostConfig(t *testing.T) {
 	t.Run("returns true for exact host matches in verbose ssh output", func(t *testing.T) {
 		config := []byte(`debug1: /tmp/config line 1: Applying options for Board,board-alt