jpictl: refactor dump to support TOML, JSON and YAML

Signed-off-by: Alejandro Mery <amery@jpi.io>

cmd/jpictl/dump.go

@@ -2,27 +2,78 @@ package main
 
 import (
 	"bytes"
+	"encoding/json"
+	"io"
 	"os"
 
 	"github.com/burntSushi/toml"
 	"github.com/spf13/cobra"
+	"gopkg.in/yaml.v3"
 
 	"git.jpi.io/amery/jpictl/pkg/zones"
 )
 
+// Encoder represents an object that encodes another internally
+type Encoder interface {
+	Encode(any) error
+}
+
+// Encoding represents a type of [Encoder]
+type Encoding int
+
+const (
+	// TOMLEncoding represents TOML encoding
+	TOMLEncoding Encoding = iota
+	// JSONEncoding represents JSON encoding
+	JSONEncoding
+	// YAMLEncoding represents YAML encoding
+	YAMLEncoding
+)
+
+// NewJSONEncoder returns a JSON [Encoder] to work on the given [io.Writer]
+func NewJSONEncoder(w io.Writer) Encoder {
+	enc := json.NewEncoder(w)
+	enc.SetIndent(``, `  `)
+	return enc
+}
+
+// NewYAMLEncoder returns a YAML [Encoder] to work on the given [io.Writer]
+func NewYAMLEncoder(w io.Writer) Encoder {
+	enc := yaml.NewEncoder(w)
+	enc.SetIndent(2)
+	return enc
+}
+
+// NewTOMLEncoder returns a TOML [Encoder] to work on the given [io.Writer]
+func NewTOMLEncoder(w io.Writer) Encoder {
+	enc := toml.NewEncoder(w)
+	return enc
+}
+
+const encoding = TOMLEncoding
+
 // Command
 var dumpCmd = &cobra.Command{
 	Use:   "dump",
-	Short: "generates a toml representation of the config",
+	Short: "generates a text representation of the config",
 	RunE: func(_ *cobra.Command, _ []string) error {
 		var buf bytes.Buffer
+		var enc Encoder
 
 		m, err := zones.New(cfg.Base, cfg.Domain)
 		if err != nil {
 			return err
 		}
 
-		enc := toml.NewEncoder(&buf)
+		switch encoding {
+		case JSONEncoding:
+			enc = NewJSONEncoder(&buf)
+		case YAMLEncoding:
+			enc = NewYAMLEncoder(&buf)
+		default:
+			enc = NewTOMLEncoder(&buf)
+		}
+
 		if err = enc.Encode(m); err != nil {
 			return err
 		}