Code refactoring for #1744

pkg/creds/README.md

@@ -0,0 +1,7 @@
+# Credentials
+
+This module allows you to get variables:
+
+- from custom storage (ex. config file)
+- from [credential files](https://systemd.io/CREDENTIALS/)
+- from environment variables

pkg/creds/creds.go

@@ -0,0 +1,79 @@
+package creds
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+type Storage interface {
+	SetValue(name, value string) error
+	GetValue(name string) (string, bool)
+}
+
+var storage Storage
+
+func SetStorage(s Storage) {
+	storage = s
+}
+
+func SetValue(name, value string) error {
+	if storage == nil {
+		return errors.New("credentials: storage not initialized")
+	}
+	if err := storage.SetValue(name, value); err != nil {
+		return err
+	}
+	AddSecret(value)
+	return nil
+}
+
+func GetValue(name string) (value string, ok bool) {
+	value, ok = getValue(name)
+	AddSecret(value)
+	return
+}
+
+func getValue(name string) (string, bool) {
+	if storage != nil {
+		if value, ok := storage.GetValue(name); ok {
+			return value, true
+		}
+	}
+
+	if dir, ok := os.LookupEnv("CREDENTIALS_DIRECTORY"); ok {
+		if value, _ := os.ReadFile(filepath.Join(dir, name)); value != nil {
+			return strings.TrimSpace(string(value)), true
+		}
+	}
+
+	return os.LookupEnv(name)
+}
+
+// ReplaceVars - support format ${CAMERA_PASSWORD} and ${RTSP_USER:admin}
+func ReplaceVars(data []byte) []byte {
+	re := regexp.MustCompile(`\${([^}{]+)}`)
+	return re.ReplaceAllFunc(data, func(match []byte) []byte {
+		key := string(match[2 : len(match)-1])
+
+		var def string
+		var defok bool
+
+		if i := strings.IndexByte(key, ':'); i > 0 {
+			key, def = key[:i], key[i+1:]
+			defok = true
+		}
+
+		if value, ok := GetValue(key); ok {
+			return []byte(value)
+		}
+
+		if defok {
+			return []byte(def)
+		}
+
+		return match
+	})
+}

pkg/creds/secrets.go

@@ -0,0 +1,83 @@
+package creds
+
+import (
+	"io"
+	"net/http"
+	"slices"
+	"strings"
+	"sync"
+)
+
+func AddSecret(value string) {
+	if value == "" {
+		return
+	}
+
+	secretsMu.Lock()
+	defer secretsMu.Unlock()
+
+	if slices.Contains(secrets, value) {
+		return
+	}
+
+	secrets = append(secrets, value)
+	secretsReplacer = nil
+}
+
+var secrets []string
+var secretsMu sync.Mutex
+var secretsReplacer *strings.Replacer
+
+func getReplacer() *strings.Replacer {
+	secretsMu.Lock()
+	defer secretsMu.Unlock()
+
+	if secretsReplacer == nil {
+		oldnew := make([]string, 0, 2*len(secrets))
+		for _, s := range secrets {
+			oldnew = append(oldnew, s, "***")
+		}
+		secretsReplacer = strings.NewReplacer(oldnew...)
+	}
+
+	return secretsReplacer
+}
+
+func SecretString(s string) string {
+	re := getReplacer()
+	return re.Replace(s)
+}
+
+func SecretWriter(w io.Writer) io.Writer {
+	return &secretWriter{w}
+}
+
+type secretWriter struct {
+	w io.Writer
+}
+
+func (s *secretWriter) Write(b []byte) (int, error) {
+	re := getReplacer()
+	return re.WriteString(s.w, string(b))
+}
+
+type secretResponse struct {
+	w http.ResponseWriter
+}
+
+func (s *secretResponse) Header() http.Header {
+	return s.w.Header()
+}
+
+func (s *secretResponse) Write(b []byte) (int, error) {
+	re := getReplacer()
+	return re.WriteString(s.w, string(b))
+}
+
+func (s *secretResponse) WriteHeader(statusCode int) {
+	s.w.WriteHeader(statusCode)
+}
+
+func SecretResponse(w http.ResponseWriter) http.ResponseWriter {
+	return &secretResponse{w}
+}

pkg/creds/secrets_test.go

@@ -0,0 +1,15 @@
+package creds
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestString(t *testing.T) {
+	AddSecret("admin")
+	AddSecret("pa$$word")
+
+	s := SecretString("rtsp://admin:pa$$word@192.168.1.123/stream1")
+	require.Equal(t, "rtsp://***:***@192.168.1.123/stream1", s)
+}