add yaml support

types/encoder.go

@@ -0,0 +1,25 @@
+package types
+
+import (
+	"encoding/json"
+	"io"
+
+	"github.com/ghodss/yaml"
+)
+
+func JSONEncoder(writer io.Writer, v interface{}) error {
+	return json.NewEncoder(writer).Encode(v)
+}
+
+func YAMLEncoder(writer io.Writer, v interface{}) error {
+	data, err := json.Marshal(v)
+	if err != nil {
+		return err
+	}
+	buf, err := yaml.JSONToYAML(data)
+	if err != nil {
+		return err
+	}
+	_, err = writer.Write(buf)
+	return err
+}