datasift / storyplayer

 * @return Iterator

 *         a hostid that matches the role

 */

function firstHostWithRole($roleName)

{

    $listOfHosts = fromRolesTable()->getDetailsForRole($roleName);

    if (!count(get_object_vars($listOfHosts))) {

        throw new E5xx_ActionFailed(__METHOD__, "unknown role '{$roleName}' or no hosts for that role");

    }

    // what are we doing?

    $log = usingLog()->startAction("for the first host with role '{$roleName}' ... ");

    // we yield a single host ID ...

    $hostsAsArray = get_object_vars($listOfHosts);

    $hostDetails  = array_pop($hostsAsArray);

    yield($hostDetails->hostId);

    // all done

    $log->endAction();

}

/**

 * iterate over all hosts that match the given role, and return only the last one

 * @return Iterator

 *         a hostid that matches the role

 */

function lastHostWithRole($roleName)

{

    $listOfHosts = fromRolesTable()->getDetailsForRole($roleName);

    if (!count(get_object_vars($listOfHosts))) {

        throw new E5xx_ActionFailed(__METHOD__, "unknown role '{$roleName}' or no hosts for that role");

    }

    // what are we doing?

    $log = usingLog()->startAction("for the last host with role '{$roleName}' ... ");

    // we yield a single host ID ...

    $hostsAsArray = get_object_vars($listOfHosts);

    $hostDetails = end($hostsAsArray);

    yield($hostDetails->hostId);

    // all done

    $log->endAction();

}

/**

 * iterate over all hosts that match the given role