aggregate masq sync errors

images/kindnetd/cmd/kindnetd/masq.go

@@ -18,6 +18,7 @@ package main
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"time"
 
@@ -55,23 +56,23 @@ type IPMasqAgent struct {
 // SyncRulesForever syncs ip masquerade rules forever
 // these rules only needs to be installed once, but we run it periodically to check that are
 // not deleted by an external program. It fails if can't sync the rules during 3 iterations
-// TODO: aggregate errors
 func (ma *IPMasqAgent) SyncRulesForever(ctx context.Context, interval time.Duration) error {
-	errs := 0
+	var errs []error
 	ticker := time.NewTicker(interval)
 	defer ticker.Stop()
 
 	for {
 		if err := ma.SyncRules(); err != nil {
-			errs++
-			if errs > 3 {
-				return fmt.Errorf("Can't synchronize rules after 3 attempts: %v", err)
+			errs = append(errs, fmt.Errorf("failed to synchronize rules at %s: %v", time.Now(), err))
+			if len(errs) > 3 {
+				return fmt.Errorf("Can't synchronize rules after 3 attempts: %w", err)
 			}
 		} else {
-			errs = 0
+			errs = errs[:0]
 		}
 		select {
 		case <-ctx.Done():
+			return errors.Join(errs...)
 		case <-ticker.C:
 		}
 	}