fix dupulicate assets url (#275)

Signed-off-by: YZ775 <yuzuki-mimura@cybozu.co.jp>

models/etcd/asset_updater.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"math/rand"
 	"net/http"
+	"slices"
 	"strconv"
 	"time"
 
@@ -41,7 +42,13 @@ RETRY:
 		return nil
 	}
 
+	currentURLs := slices.Clone(a.URLs)
 	a.URLs = append(a.URLs, d.myURL("/api/v1/assets", a.Name))
+	slices.Sort(a.URLs)
+	slices.Compact(a.URLs)
+	if slices.Equal(currentURLs, a.URLs) || len(a.URLs) > maxAssetURLs {
+		return nil
+	}
 	key := KeyAssets + a.Name
 
 	j, err := json.Marshal(a)
@@ -120,11 +127,9 @@ func (d *driver) downloadAsset(ctx context.Context, asset *sabakan.Asset) error
 		return err
 	}
 
-	if len(asset.URLs) < maxAssetURLs {
-		err = d.addAssetURL(ctx, asset)
-		if err != nil {
-			return err
-		}
+	err = d.addAssetURL(ctx, asset)
+	if err != nil {
+		return err
 	}
 
 	return nil