Add admin config page and runtime-tunable upload/rate-limit settings

internal/config/service.go

@@ -0,0 +1,125 @@
+package config
+
+import (
+	"errors"
+	"strconv"
+	"sync"
+	"time"
+
+	"gorm.io/gorm"
+)
+
+type Service struct {
+	repo *Repository
+
+	// Small in-memory cache to avoid hitting the DB on every request.
+	// Updated on SetString; lazy-filled on first Get.
+	mu    sync.RWMutex
+	cache map[string]string
+}
+
+func NewService(r *Repository) *Service {
+	return &Service{repo: r, cache: make(map[string]string)}
+}
+
+func (s *Service) List() ([]ConfigEntry, error) {
+	entries, err := s.repo.List()
+	if err != nil {
+		return nil, err
+	}
+	// refresh cache snapshot
+	s.mu.Lock()
+	for _, e := range entries {
+		s.cache[e.Key] = e.Value
+	}
+	s.mu.Unlock()
+	return entries, nil
+}
+
+func (s *Service) SetString(key, value string) error {
+	if err := s.repo.Upsert(key, value); err != nil {
+		return err
+	}
+	s.mu.Lock()
+	s.cache[key] = value
+	s.mu.Unlock()
+	return nil
+}
+
+func (s *Service) GetStringDefault(key, def string) string {
+	s.mu.RLock()
+	v, ok := s.cache[key]
+	s.mu.RUnlock()
+	if ok {
+		if v == "" {
+			return def
+		}
+		return v
+	}
+
+	e, err := s.repo.Get(key)
+	if err != nil {
+		return def
+	}
+
+	s.mu.Lock()
+	s.cache[key] = e.Value
+	s.mu.Unlock()
+
+	if e.Value == "" {
+		return def
+	}
+	return e.Value
+}
+
+func (s *Service) GetIntDefault(key string, def int) int {
+	v := s.GetStringDefault(key, "")
+	if v == "" {
+		return def
+	}
+	n, err := strconv.Atoi(v)
+	if err != nil {
+		return def
+	}
+	return n
+}
+
+func (s *Service) GetInt64Default(key string, def int64) int64 {
+	v := s.GetStringDefault(key, "")
+	if v == "" {
+		return def
+	}
+	n, err := strconv.ParseInt(v, 10, 64)
+	if err != nil {
+		return def
+	}
+	return n
+}
+
+func (s *Service) GetBoolDefault(key string, def bool) bool {
+	v := s.GetStringDefault(key, "")
+	if v == "" {
+		return def
+	}
+	b, err := strconv.ParseBool(v)
+	if err != nil {
+		return def
+	}
+	return b
+}
+
+func (s *Service) GetDurationSecondsDefault(key string, def time.Duration) time.Duration {
+	v := s.GetStringDefault(key, "")
+	if v == "" {
+		return def
+	}
+	n, err := strconv.Atoi(v)
+	if err != nil {
+		return def
+	}
+	return time.Duration(n) * time.Second
+}
+
+func IsNotFound(err error) bool {
+	return errors.Is(err, gorm.ErrRecordNotFound)
+}