Add base64 encoding support to file provider

Signed-off-by: Stepan Kokhanovskiy <[email protected]>

README.md

@@ -576,6 +576,7 @@ Examples:
 
 - `ref+file://foo/bar` loads the file at `foo/bar`
 - `ref+file:///home/foo/bar` loads the file at `/home/foo/bar`
+- `ref+file://foo/bar?encode=base64` loads the file at `foo/bar` and encodes its content to a base64 string
 - `ref+file://some.yaml#/foo/bar` loads the YAML file at `some.yaml` and reads the value for the path `$.foo.bar`.
   Let's say `some.yaml` contains `{"foo":{"bar":"BAR"}}`, `key1: ref+file://some.yaml#/foo/bar` results in `key1: BAR`.
 

pkg/providers/file/file.go

@@ -1,6 +1,8 @@
 package file
 
 import (
+	"encoding/base64"
+	"fmt"
 	"os"
 	"strings"
 
@@ -10,20 +12,34 @@ import (
 )
 
 type provider struct {
+	Encode string
 }
 
 func New(cfg api.StaticConfig) *provider {
 	p := &provider{}
+	p.Encode = cfg.String("encode")
+	if p.Encode == "" {
+		p.Encode = "raw"
+	}
 	return p
 }
 
 func (p *provider) GetString(key string) (string, error) {
+	res := ""
 	key = strings.TrimSuffix(key, "/")
 	bs, err := os.ReadFile(key)
 	if err != nil {
 		return "", err
 	}
-	return string(bs), nil
+	switch p.Encode {
+	case "raw":
+		res = string(bs)
+	case "base64":
+		res = base64.StdEncoding.EncodeToString(bs)
+	default:
+		return "", fmt.Errorf("Unsupported encode parameter: '%s'.", p.Encode)
+	}
+	return res, nil
 }
 
 func (p *provider) GetStringMap(key string) (map[string]interface{}, error) {