controller_manager.cpp

Go to the documentation of this file.

// Copyright (C) 2012, hiDOF, INC and Willow Garage, Inc
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
//   * Neither the names of Willow Garage, Inc., hiDOF Inc, nor the names of its
//     contributors may be used to endorse or promote products derived from
//     this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
/*
 * Author: Wim Meeussen
 */
 
#include "controller_manager/controller_manager.h"
#include <algorithm>
#include <chrono>
#include <mutex>
#include <sstream>
#include <thread>
#include <ros/console.h>
#include <controller_manager/controller_loader.h>
#include <controller_manager_msgs/ControllerState.h>
 
namespace controller_manager
{
 
 
ControllerManager::ControllerManager(hardware_interface::RobotHW *robot_hw, const ros::NodeHandle& nh) :
  robot_hw_(robot_hw),
  root_nh_(nh),
  cm_node_(nh, "controller_manager")
{
  // create controller loader
  controller_loaders_.push_back(
    ControllerLoaderInterfaceSharedPtr(new ControllerLoader<controller_interface::ControllerBase>("controller_interface",
                                                                                                  "controller_interface::ControllerBase") ) );
 
  // Advertise services (this should be the last thing we do in init)
  srv_list_controllers_ = cm_node_.advertiseService("list_controllers", &ControllerManager::listControllersSrv, this);
  srv_list_controller_types_ = cm_node_.advertiseService("list_controller_types", &ControllerManager::listControllerTypesSrv, this);
  srv_load_controller_ = cm_node_.advertiseService("load_controller", &ControllerManager::loadControllerSrv, this);
  srv_unload_controller_ = cm_node_.advertiseService("unload_controller", &ControllerManager::unloadControllerSrv, this);
  srv_switch_controller_ = cm_node_.advertiseService("switch_controller", &ControllerManager::switchControllerSrv, this);
  srv_reload_libraries_ = cm_node_.advertiseService("reload_controller_libraries", &ControllerManager::reloadControllerLibrariesSrv, this);
}
 
 
// Must be realtime safe.
void ControllerManager::update(const ros::Time& time, const ros::Duration& period, bool reset_controllers)
{
  used_by_realtime_ = current_controllers_list_;
  
  // Restart all running controllers if motors are re-enabled
  if (reset_controllers){
    for (const auto& controller : controllers_lists_[used_by_realtime_]){
      if (controller.c->isRunning()){
        controller.c->stopRequest(time);
        controller.c->startRequest(time);
      }
    }
  }
 
 
  // Update all controllers
  for (const auto& controller : controllers_lists_[used_by_realtime_])
    controller.c->updateRequest(time, period);
 
  // there are controllers to start/stop
  if (switch_params_.do_switch)
  {
    manageSwitch(time);
  }
}
 
controller_interface::ControllerBase* ControllerManager::getControllerByName(const std::string& name)
{
  // Lock recursive mutex in this context
  std::lock_guard<std::recursive_mutex> guard(controllers_lock_);
 
  for (const auto& controller : controllers_lists_[current_controllers_list_])
  {
    if (controller.info.name == name)
      return controller.c.get();
  }
  return nullptr;
}
 
void ControllerManager::getControllerNames(std::vector<std::string> &names)
{
  std::lock_guard<std::recursive_mutex> guard(controllers_lock_);
  names.clear();
  for (const auto& controller : controllers_lists_[current_controllers_list_])
  {
    names.push_back(controller.info.name);
  }
}
 
void ControllerManager::manageSwitch(const ros::Time& time)
{
  // switch hardware interfaces (if any)
  if (!switch_params_.started)
  {
    robot_hw_->doSwitch(switch_start_list_, switch_stop_list_);
    switch_params_.started = true;
  }
 
  stopControllers(time);
 
  // start controllers once the switch is fully complete
  if (!switch_params_.start_asap)
  {
    startControllers(time);
  }
  // start controllers as soon as their required joints are done switching
  else
  {
    startControllersAsap(time);
  }
}
 
void ControllerManager::stopControllers(const ros::Time& time)
{
  // stop controllers
  for (const auto& request : stop_request_)
  {
    if (request->isRunning())
    {
      request->stopRequest(time);
    }
  }
}
 
void ControllerManager::startControllers(const ros::Time& time)
{
  // start controllers
  if (robot_hw_->switchResult() == hardware_interface::RobotHW::SwitchState::DONE)
  {
    for (const auto& request : start_request_)
    {
      request->startRequest(time);
    }
 
    switch_params_.do_switch = false;
  }
  // abort controllers in case of error or timeout (if set)
  else if ((robot_hw_->switchResult() == hardware_interface::RobotHW::SwitchState::ERROR) ||
           (switch_params_.timeout > 0.0 &&
            (time - switch_params_.init_time).toSec() > switch_params_.timeout))
  {
    for (const auto& request : start_request_)
    {
      request->abortRequest(time);
    }
 
    switch_params_.do_switch = false;
  }
  // wait controllers
  else
  {
    for (const auto& request : start_request_)
    {
      request->waitRequest(time);
    }
  }
}
 
void ControllerManager::startControllersAsap(const ros::Time& time)
{
  // start controllers if possible
  for (const auto& request : start_request_)
  {
    if (!request->isRunning())
    {
      // find the info from this controller
      for (const auto& controller : controllers_lists_[current_controllers_list_])
      {
        if (request == controller.c.get())
        {
          // ready to start
          if (robot_hw_->switchResult(controller.info) == hardware_interface::RobotHW::SwitchState::DONE)
          {
            request->startRequest(time);
          }
          // abort on error or timeout (if set)
          else if ((robot_hw_->switchResult(controller.info) == hardware_interface::RobotHW::SwitchState::ERROR) ||
                   (switch_params_.timeout > 0.0 &&
                    (time - switch_params_.init_time).toSec() > switch_params_.timeout))
          {
            request->abortRequest(time);
          }
          // controller is waiting
          else
          {
            request->waitRequest(time);
          }
        }
        continue;
      }
    }
  }
 
  // all needed controllers started or aborted, switch done
  if (std::all_of(start_request_.begin(), start_request_.end(),
                  [](controller_interface::ControllerBase *request) {
                    return request->isRunning() || request->isAborted();
                  }))
  {
    switch_params_.do_switch = false;
  }
}
 
bool ControllerManager::loadController(const std::string& name)
{
  ROS_DEBUG("Will load controller '%s'", name.c_str());
 
  // lock controllers
  std::lock_guard<std::recursive_mutex> guard(controllers_lock_);
 
  // get reference to controller list
  int free_controllers_list = (current_controllers_list_ + 1) % 2;
  while (ros::ok() && free_controllers_list == used_by_realtime_)
  {
    if (!ros::ok())
    {
      return false;
    }
    std::this_thread::sleep_for(std::chrono::microseconds(200));
  }
  std::vector<ControllerSpec>
    &from = controllers_lists_[current_controllers_list_],
    &to = controllers_lists_[free_controllers_list];
  to.clear();
 
  // Copy all controllers from the 'from' list to the 'to' list
  for (const auto& controller : from)
    to.push_back(controller);
 
  // Checks that we're not duplicating controllers
  for (const auto& controller : to)
  {
    if (controller.info.name == name)
    {
      to.clear();
      ROS_ERROR("A controller named '%s' was already loaded inside the controller manager", name.c_str());
      return false;
    }
  }
 
  ros::NodeHandle c_nh;
  // Constructs the controller
  try{
    c_nh = ros::NodeHandle(root_nh_, name);
  }
  catch(std::exception &e) {
    ROS_ERROR("Exception thrown while constructing nodehandle for controller with name '%s':\n%s", name.c_str(), e.what());
    return false;
  }
  catch(...){
    ROS_ERROR("Exception thrown while constructing nodehandle for controller with name '%s'", name.c_str());
    return false;
  }
  controller_interface::ControllerBaseSharedPtr c;
  std::string type;
  if (c_nh.getParam("type", type))
  {
    ROS_DEBUG("Constructing controller '%s' of type '%s'", name.c_str(), type.c_str());
    try
    {
      // Trying loading the controller using all of our controller loaders. Exit once we've found the first valid loaded controller
      auto it = controller_loaders_.begin();
      while (!c && it != controller_loaders_.end())
      {
        for (const auto& cur_type : (*it)->getDeclaredClasses()){
          if (type == cur_type){
            c = (*it)->createInstance(type);
          }
        }
        ++it;
      }
    }
    catch (const std::runtime_error &ex)
    {
      ROS_ERROR("Could not load class '%s': %s", type.c_str(), ex.what());
    }
  }
  else
  {
    ROS_ERROR("Could not load controller '%s' because the type was not specified. Did you load the controller configuration on the parameter server (namespace: '%s')?", name.c_str(), c_nh.getNamespace().c_str());
    to.clear();
    return false;
  }
 
  // checks if controller was constructed
  if (!c)
  {
    ROS_ERROR("Could not load controller '%s' because controller type '%s' does not exist.",  name.c_str(), type.c_str());
    ROS_ERROR("Use 'rosservice call controller_manager/list_controller_types' to get the available types");
    to.clear();
    return false;
  }
 
  // Initializes the controller
  ROS_DEBUG("Initializing controller '%s'", name.c_str());
  bool initialized;
  controller_interface::ControllerBase::ClaimedResources claimed_resources; // Gets populated during initRequest call
  try{
    initialized = c->initRequest(robot_hw_, root_nh_, c_nh, claimed_resources);
  }
  catch(std::exception &e){
    ROS_ERROR("Exception thrown while initializing controller '%s'.\n%s", name.c_str(), e.what());
    initialized = false;
  }
  catch(...){
    ROS_ERROR("Exception thrown while initializing controller '%s'", name.c_str());
    initialized = false;
  }
  if (!initialized)
  {
    to.clear();
    ROS_ERROR("Initializing controller '%s' failed", name.c_str());
    return false;
  }
  ROS_DEBUG("Initialized controller '%s' successful", name.c_str());
 
  // Adds the controller to the new list
  to.resize(to.size() + 1);
  to.back().info.type = type;
  to.back().info.name = name;
  to.back().info.claimed_resources = claimed_resources;
  to.back().c = c;
 
  // Destroys the old controllers list when the realtime thread is finished with it.
  int former_current_controllers_list_ = current_controllers_list_;
  current_controllers_list_ = free_controllers_list;
  while (ros::ok() && used_by_realtime_ == former_current_controllers_list_)
  {
    if (!ros::ok())
    {
      return false;
    }
    std::this_thread::sleep_for(std::chrono::microseconds(200));
  }
  from.clear();
 
  ROS_DEBUG("Successfully load controller '%s'", name.c_str());
  return true;
}
 
 
bool ControllerManager::unloadController(const std::string &name)
{
  ROS_DEBUG("Will unload controller '%s'", name.c_str());
 
  // lock the controllers
  std::lock_guard<std::recursive_mutex> guard(controllers_lock_);
 
  // get reference to controller list
  int free_controllers_list = (current_controllers_list_ + 1) % 2;
  while (ros::ok() && free_controllers_list == used_by_realtime_)
  {
    if (!ros::ok())
    {
      return false;
    }
    std::this_thread::sleep_for(std::chrono::microseconds(200));
  }
  std::vector<ControllerSpec>
    &from = controllers_lists_[current_controllers_list_],
    &to = controllers_lists_[free_controllers_list];
  to.clear();
 
  // Transfers the running controllers over, skipping the one to be removed and the running ones.
  bool removed = false;
  for (const auto& controller : from)
  {
    if (controller.info.name == name){
      if (controller.c->isRunning()){
        to.clear();
        ROS_ERROR("Could not unload controller with name '%s' because it is still running",
                  name.c_str());
        return false;
      }
      removed = true;
    }
    else
      to.push_back(controller);
  }
 
  // Fails if we could not remove the controllers
  if (!removed)
  {
    to.clear();
    ROS_ERROR("Could not unload controller with name '%s' because no controller with this name exists",
              name.c_str());
    return false;
  }
 
  // Destroys the old controllers list when the realtime thread is finished with it.
  ROS_DEBUG("Realtime switches over to new controller list");
  int former_current_controllers_list_ = current_controllers_list_;
  current_controllers_list_ = free_controllers_list;
  while (ros::ok() && used_by_realtime_ == former_current_controllers_list_)
  {
    if (!ros::ok())
    {
      return false;
    }
    std::this_thread::sleep_for(std::chrono::microseconds(200));
  }
  ROS_DEBUG("Destruct controller");
  from.clear();
  ROS_DEBUG("Destruct controller finished");
 
  ROS_DEBUG("Successfully unloaded controller '%s'", name.c_str());
  return true;
}
 
 
bool ControllerManager::switchController(const std::vector<std::string>& start_controllers,
                                         const std::vector<std::string>& stop_controllers,
                                         int strictness, bool start_asap, double timeout)
{
  switch_params_ = SwitchParams();
 
  if (!stop_request_.empty() || !start_request_.empty())
    ROS_FATAL("The internal stop and start request lists are not empty at the beginning of the swithController() call. This should not happen.");
 
  if (strictness == 0){
    ROS_WARN("Controller Manager: To switch controllers you need to specify a strictness level of controller_manager_msgs::SwitchController::STRICT (%d) or ::BEST_EFFORT (%d). Defaulting to ::BEST_EFFORT.",
             controller_manager_msgs::SwitchController::Request::STRICT,
             controller_manager_msgs::SwitchController::Request::BEST_EFFORT);
    strictness = controller_manager_msgs::SwitchController::Request::BEST_EFFORT;
  }
 
  ROS_DEBUG("switching controllers:");
  for (const auto& controller : start_controllers)
    ROS_DEBUG(" - starting controller '%s'", controller.c_str());
  for (const auto& controller : stop_controllers)
    ROS_DEBUG(" - stopping controller '%s'", controller.c_str());
 
  // lock controllers
  std::lock_guard<std::recursive_mutex> guard(controllers_lock_);
 
  controller_interface::ControllerBase* ct;
  // list all controllers to stop
  for (const auto& controller : stop_controllers)
  {
    ct = getControllerByName(controller);
    if (ct == nullptr){
      if (strictness ==  controller_manager_msgs::SwitchController::Request::STRICT){
        ROS_ERROR("Could not stop controller with name '%s' because no controller with this name exists",
                  controller.c_str());
        stop_request_.clear();
        return false;
      }
      else{
        ROS_DEBUG("Could not stop controller with name '%s' because no controller with this name exists",
                  controller.c_str());
      }
    }
    else{
      ROS_DEBUG("Found controller '%s' that needs to be stopped in list of controllers",
                controller.c_str());
      stop_request_.push_back(ct);
    }
  }
  ROS_DEBUG("Stop request vector has size %i", (int)stop_request_.size());
 
  // list all controllers to start
  for (const auto& controller : start_controllers)
  {
    ct = getControllerByName(controller);
    if (ct == nullptr){
      if (strictness ==  controller_manager_msgs::SwitchController::Request::STRICT){
        ROS_ERROR("Could not start controller with name '%s' because no controller with this name exists",
                  controller.c_str());
        stop_request_.clear();
        start_request_.clear();
        return false;
      }
      else{
        ROS_DEBUG("Could not start controller with name '%s' because no controller with this name exists",
                  controller.c_str());
      }
    }
    else{
      ROS_DEBUG("Found controller '%s' that needs to be started in list of controllers",
                controller.c_str());
      start_request_.push_back(ct);
    }
  }
  ROS_DEBUG("Start request vector has size %i", (int)start_request_.size());
 
  // Do the resource management checking
  std::list<hardware_interface::ControllerInfo> info_list;
  switch_start_list_.clear();
  switch_stop_list_.clear();
 
  const auto &controllers = controllers_lists_[current_controllers_list_];
  for (const auto& controller : controllers)
  {
    bool in_stop_list  = false;
    for (const auto& request : stop_request_)
    {
      if (request == controller.c.get())
      {
        in_stop_list = true;
        break;
      }
    }
 
    bool in_start_list = false;
    for (const auto& request : start_request_)
    {
      if (request == controller.c.get())
      {
        in_start_list = true;
        break;
      }
    }
 
    const bool is_running = controller.c->isRunning();
    const hardware_interface::ControllerInfo &info = controller.info;
 
    if(!is_running && in_stop_list){ // check for double stop
      if(strictness ==  controller_manager_msgs::SwitchController::Request::STRICT){
        ROS_ERROR_STREAM("Could not stop controller '" << info.name << "' since it is not running");
        stop_request_.clear();
        start_request_.clear();
        return false;
      } else {
        in_stop_list = false;
      }
    }
 
    if(is_running && !in_stop_list && in_start_list){ // check for doubled start
      if(strictness ==  controller_manager_msgs::SwitchController::Request::STRICT){
        ROS_ERROR_STREAM("Controller '" << info.name << "' is already running");
        stop_request_.clear();
        start_request_.clear();
        return false;
      } else {
        in_start_list = false;
      }
    }
 
    if(in_stop_list && in_start_list){ // duplicate start/stop
        ROS_ERROR_STREAM("Could no start or stop controller '" << info.name << "' because of conflicting switching command");
        stop_request_.clear();
        start_request_.clear();
        return false;
    }
 
    if(is_running && in_stop_list && !in_start_list){ // running and real stop
      switch_stop_list_.push_back(info);
    }
    else if(!is_running && !in_stop_list && in_start_list){ // start, but no restart
      switch_start_list_.push_back(info);
     }
 
    bool add_to_list = is_running;
    if (in_stop_list)
      add_to_list = false;
    if (in_start_list)
      add_to_list = true;
 
    if (add_to_list)
      info_list.push_back(info);
  }
 
  bool in_conflict = robot_hw_->checkForConflict(info_list);
  if (in_conflict)
  {
    ROS_ERROR("Could not switch controllers, due to resource conflict");
    stop_request_.clear();
    start_request_.clear();
    return false;
  }
 
  if (!robot_hw_->prepareSwitch(switch_start_list_, switch_stop_list_))
  {
    ROS_ERROR("Could not switch controllers. The hardware interface combination for the requested controllers is unfeasible.");
    stop_request_.clear();
    start_request_.clear();
    return false;
  }
 
  // start the atomic controller switching
  switch_params_.strictness = strictness;
  switch_params_.start_asap = start_asap;
  switch_params_.init_time = ros::Time::now();
  switch_params_.timeout = timeout;
  switch_params_.do_switch = true;
 
  // wait until switch is finished
  ROS_DEBUG("Request atomic controller switch from realtime loop");
  auto start_time = std::chrono::system_clock::now();
  bool timed_out = false;
  while (ros::ok() && switch_params_.do_switch)
  {
    if (!ros::ok())
    {
      return false;
    }
    std::chrono::duration<double> diff = std::chrono::system_clock::now() - start_time;
    if (diff.count() < timeout+1.0 || timeout == 0){
        std::this_thread::sleep_for(std::chrono::microseconds(100));
    } else {
        ROS_DEBUG("Timed out while switching controllers. Exiting...");
        timed_out = true;
        break;
    }
  }
  start_request_.clear();
  stop_request_.clear();
  if(timed_out){
      ROS_DEBUG("Exited wait until switch is finished loop using non-ROS-time timeout");
      return false;
  }
  ROS_DEBUG("Successfully switched controllers");
  return true;
}
 
 
bool ControllerManager::reloadControllerLibrariesSrv(
  controller_manager_msgs::ReloadControllerLibraries::Request &req,
  controller_manager_msgs::ReloadControllerLibraries::Response &resp)
{
  // lock services
  ROS_DEBUG("reload libraries service called");
  std::lock_guard<std::mutex> guard(services_lock_);
  ROS_DEBUG("reload libraries service locked");
 
  // only reload libraries if no controllers are running
  std::vector<std::string> controllers;
  getControllerNames(controllers);
  if (!controllers.empty() && !req.force_kill){
    ROS_ERROR("Controller manager: Cannot reload controller libraries because there are still %i controllers running", (int)controllers.size());
    resp.ok = false;
    return true;
  }
 
  // kill running controllers if requested
  if (!controllers.empty()){
    ROS_INFO("Controller manager: Killing all running controllers");
    std::vector<std::string> empty;
    if (!switchController(empty,controllers, controller_manager_msgs::SwitchController::Request::BEST_EFFORT)){
      ROS_ERROR("Controller manager: Cannot reload controller libraries because failed to stop running controllers");
      resp.ok = false;
      return true;
    }
    for (const auto& controller : controllers){
      if (!unloadController(controller)){
        ROS_ERROR("Controller manager: Cannot reload controller libraries because failed to unload controller '%s'",
                  controller.c_str());
        resp.ok = false;
        return true;
      }
    }
    getControllerNames(controllers);
  }
  assert(controllers.empty());
 
  // Force a reload on all the PluginLoaders (internally, this recreates the plugin loaders)
  for (const auto& controller_loader : controller_loaders_)
  {
    controller_loader->reload();
    ROS_INFO("Controller manager: reloaded controller libraries for '%s'", controller_loader->getName().c_str());
  }
 
  resp.ok = true;
 
  ROS_DEBUG("reload libraries service finished");
  return true;
}
 
 
bool ControllerManager::listControllerTypesSrv(
  controller_manager_msgs::ListControllerTypes::Request &req,
  controller_manager_msgs::ListControllerTypes::Response &resp)
{
  // pretend to use the request
  (void) req;
 
  // lock services
  ROS_DEBUG("list types service called");
  std::lock_guard<std::mutex> guard(services_lock_);
  ROS_DEBUG("list types service locked");
 
  for (const auto& controller_loader : controller_loaders_)
  {
    std::vector<std::string> cur_types = controller_loader->getDeclaredClasses();
    for (const auto& cur_type : cur_types)
    {
      resp.types.push_back(cur_type);
      resp.base_classes.push_back(controller_loader->getName());
    }
  }
 
  ROS_DEBUG("list types service finished");
  return true;
}
 
 
bool ControllerManager::listControllersSrv(
  controller_manager_msgs::ListControllers::Request &req,
  controller_manager_msgs::ListControllers::Response &resp)
{
  // pretend to use the request
  (void) req;
 
  // lock services
  ROS_DEBUG("list controller service called");
  std::lock_guard<std::mutex> services_guard(services_lock_);
  ROS_DEBUG("list controller service locked");
 
  // lock controllers to get all names/types/states
  std::lock_guard<std::recursive_mutex> controller_guard(controllers_lock_);
  std::vector<ControllerSpec> &controllers = controllers_lists_[current_controllers_list_];
  resp.controller.resize(controllers.size());
 
  for (size_t i = 0; i < controllers.size(); ++i)
  {
    controller_manager_msgs::ControllerState& cs = resp.controller[i];
    cs.name = controllers[i].info.name;
    cs.type = controllers[i].info.type;
 
    cs.claimed_resources.clear();
    typedef std::vector<hardware_interface::InterfaceResources> ClaimedResVec;
    typedef ClaimedResVec::const_iterator ClaimedResIt;
    const ClaimedResVec& c_resources = controllers[i].info.claimed_resources;
    for (const auto& c_resource : c_resources)
    {
      controller_manager_msgs::HardwareInterfaceResources iface_res;
      iface_res.hardware_interface = c_resource.hardware_interface;
      std::copy(c_resource.resources.begin(), c_resource.resources.end(), std::back_inserter(iface_res.resources));
      cs.claimed_resources.push_back(iface_res);
    }
 
    if (controllers[i].c->isInitialized())
    {
      cs.state = "initialized";
    }
    else if (controllers[i].c->isRunning())
    {
      cs.state = "running";
    }
    else if (controllers[i].c->isStopped())
    {
      cs.state = "stopped";
    }
    else if (controllers[i].c->isWaiting())
    {
      cs.state = "waiting";
    }
    else if (controllers[i].c->isAborted())
    {
      cs.state = "aborted";
    }
    else
    {
      // should never happen
      cs.state = "unknown";
    }
  }
 
  ROS_DEBUG("list controller service finished");
  return true;
}
 
 
bool ControllerManager::loadControllerSrv(
  controller_manager_msgs::LoadController::Request &req,
  controller_manager_msgs::LoadController::Response &resp)
{
  // lock services
  ROS_DEBUG("loading service called for controller '%s' ",req.name.c_str());
  std::lock_guard<std::mutex> guard(services_lock_);
  ROS_DEBUG("loading service locked");
 
  resp.ok = loadController(req.name);
 
  ROS_DEBUG("loading service finished for controller '%s' ",req.name.c_str());
  return true;
}
 
 
bool ControllerManager::unloadControllerSrv(
  controller_manager_msgs::UnloadController::Request &req,
  controller_manager_msgs::UnloadController::Response &resp)
{
  // lock services
  ROS_DEBUG("unloading service called for controller '%s' ",req.name.c_str());
  std::lock_guard<std::mutex> guard(services_lock_);
  ROS_DEBUG("unloading service locked");
 
  resp.ok = unloadController(req.name);
 
  ROS_DEBUG("unloading service finished for controller '%s' ",req.name.c_str());
  return true;
}
 
 
bool ControllerManager::switchControllerSrv(
  controller_manager_msgs::SwitchController::Request &req,
  controller_manager_msgs::SwitchController::Response &resp)
{
  // lock services
  ROS_DEBUG("switching service called");
  std::lock_guard<std::mutex> guard(services_lock_);
  ROS_DEBUG("switching service locked");
 
  resp.ok = switchController(req.start_controllers, req.stop_controllers, req.strictness,
                             req.start_asap, req.timeout);
 
  ROS_DEBUG("switching service finished");
  return true;
}
 
void ControllerManager::registerControllerLoader(ControllerLoaderInterfaceSharedPtr controller_loader)
{
  controller_loaders_.push_back(controller_loader);
}
 
}