Implementing roles caching

Signed-off-by: Ethan Wellenreiter <ewellenreiter@gmail.com>

backend/internal/storage/cache/redis_roles.go

@@ -0,0 +1,47 @@
+package cache
+
+import (
+	"context"
+	"encoding/json"
+
+	"git.ewellenr.ca/receipt_indexer/backend/internal/storage"
+	"github.com/redis/go-redis/v9"
+)
+
+type RolesStore struct {
+	rdb *redis.Client
+}
+
+func (s *RolesStore) Get(ctx context.Context, name string) (*storage.Role, error) {
+
+	data, err := s.rdb.Get(ctx, name).Result()
+	if err == redis.Nil {
+		return nil, nil
+	} else if err != nil {
+		return nil, err
+	}
+
+	var role storage.Role
+	if data != "" {
+		err := json.Unmarshal([]byte(data), &role)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return &role, nil
+}
+
+func (s *RolesStore) Set(ctx context.Context, role *storage.Role) error {
+
+	json, err := json.Marshal(role)
+	if err != nil {
+		return err
+	}
+
+	return s.rdb.Set(ctx, role.Name, json, RolesExpTime).Err()
+}
+
+func (s *RolesStore) Delete(ctx context.Context, name string) {
+	s.rdb.Del(ctx, name)
+}