fix: adding ucind cluster with tcp connections to config

internal/cli/cli.go

@@ -137,8 +137,8 @@ func connectCluster(ctx context.Context, conn config.MachineConnection) (*client
 			KeyPath: keyPath,
 		}
 		return client.New(ctx, connector.NewSSHConnector(sshConfig))
-	} else if conn.TCP.IsValid() {
-		return client.New(ctx, connector.NewTCPConnector(conn.TCP))
+	} else if conn.TCP != nil && conn.TCP.IsValid() {
+		return client.New(ctx, connector.NewTCPConnector(*conn.TCP))
 	}
 
 	return nil, errors.New("connection configuration is invalid")

internal/cli/config/config.go

@@ -5,7 +5,7 @@ import (
 	"os"
 	"path/filepath"
 
-	"gopkg.in/yaml.v3"
+	"github.com/goccy/go-yaml"
 )
 
 type Config struct {
@@ -45,7 +45,7 @@ func (c *Config) Read() error {
 		return fmt.Errorf("read config file '%s': %w", c.path, err)
 	}
 	if err = yaml.Unmarshal(data, c); err != nil {
-		return fmt.Errorf("parse config file '%s': %w", c.path, err)
+		return fmt.Errorf("parse config file '%s': %s", c.path, yaml.FormatError(err, true, true))
 	}
 
 	return nil
@@ -62,8 +62,7 @@ func (c *Config) Save() error {
 		return fmt.Errorf("write config file '%s': %w", c.path, err)
 	}
 
-	encoder := yaml.NewEncoder(f)
-	encoder.SetIndent(2)
+	encoder := yaml.NewEncoder(f, yaml.Indent(2), yaml.IndentSequence(true))
 	if err = encoder.Encode(c); err != nil {
 		_ = f.Close()
 		return fmt.Errorf("encode config file '%s': %w", c.path, err)

internal/cli/config/connection.go

@@ -17,9 +17,11 @@ const (
 type MachineConnection struct {
 	SSH        SSHDestination `yaml:"ssh,omitempty"`
 	SSHKeyFile string         `yaml:"ssh_key_file,omitempty"`
-	TCP        netip.AddrPort `yaml:"tcp,omitempty"`
-	Host       string         `yaml:"host,omitempty"`
-	PublicKey  secret.Secret  `yaml:"public_key,omitempty"`
+	// TCP is the address and port of the machine's API server.
+	// The pointer is used to omit the field when not set. Otherwise, yaml marshalling includes an empty object.
+	TCP       *netip.AddrPort `yaml:"tcp,omitempty"`
+	Host      string          `yaml:"host,omitempty"`
+	PublicKey secret.Secret   `yaml:"public_key,omitempty"`
 }
 
 // SSHDestination represents an SSH destination string in the canonical form of "user@host:port".