Open SQLite with WAL and bound delivery re-dispatch by ownership (closes #256)

internal/delivery/target_slack.go

@@ -95,12 +95,17 @@ func (t *slackTarget) failConfig(
 	d *database.Delivery,
 	err error,
 ) {
-	t.eng.recordResult(
+	recErr := t.eng.recordResult(
 		webhookDB, d, 1,
 		false, 0, "", err.Error(), 0,
 	)
+	if recErr != nil {
+		t.eng.bookkeepingFailed(d, recErr)
 
-	t.eng.updateDeliveryStatus(
+		return
+	}
+
+	t.eng.settleStatus(
 		webhookDB, d, d.Target.Type,
 		database.DeliveryStatusFailed,
 	)