Labels HookManager::masterLaunchTaskLabelDecorator( const TaskInfo& taskInfo, const FrameworkInfo& frameworkInfo, const SlaveInfo& slaveInfo) { Lock lock(&mutex); Labels labels; foreachpair (const string& name, Hook* hook, availableHooks) { const Result<Labels>& result = hook->masterLaunchTaskLabelDecorator(taskInfo, frameworkInfo, slaveInfo); if (result.isSome()) { labels.MergeFrom(result.get()); } else if (result.isError()) { LOG(WARNING) << "Master label decorator hook failed for module '" << name << "': " << result.error(); } } return labels; }