ProcessSpawnManager.h

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/*
 * Copyright (C) 2012 by
 *   MetraLabs GmbH (MLAB), GERMANY
 * and
 *   Neuroinformatics and Cognitive Robotics Labs (NICR) at TU Ilmenau, GERMANY
 * All rights reserved.
 *
 * Contact: info@mira-project.org
 *
 * Commercial Usage:
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 *   accordance with the commercial license agreement provided with the
 *   software or, alternatively, in accordance with the terms contained in
 *   a written agreement between you and MLAB or NICR.
 *
 * GNU General Public License Usage:
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 *   General Public License version 3.0 as published by the Free Software
 *   Foundation and appearing in the file LICENSE.GPL3 included in the
 *   packaging of this file. Please review the following information to
 *   ensure the GNU General Public License version 3.0 requirements will be
 *   met: http://www.gnu.org/copyleft/gpl.html.
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 */


#ifndef _MIRA_PROCESSSPAWNMANAGER_H_
#define _MIRA_PROCESSSPAWNMANAGER_H_

#include <list>
#include <vector>

#include <boost/algorithm/string.hpp>

#include <error/Logging.h>

#include <utils/Foreach.h>
#include <utils/Path.h>
#include <utils/PathFinder.h>

#include <thread/ThreadMonitor.h>

#include <platform/Process.h>

namespace mira {


class ProcessSpawnManager
{
public:

    struct ProcessInfo
    {
        ~ProcessInfo()
        {
            if(!cleanup_cmd.empty() && std::system(NULL)) {
                if (0 != std::system(cleanup_cmd.c_str())) {
                    MIRA_LOG(WARNING) << "ProcessSpawnManager: Failed to clean up using command '" << cleanup_cmd << "'";
                }
            }
        }

        std::string getName() const {
            if(name.empty())
                return pid;
            else
                return name;
        }

        Process process;

        std::string name;
        std::string pid;
        bool respawn;
        bool required;

        // infos for respawn
        bool shutdownRecursively;
        Path executable; // the used executable
        std::vector<std::string> args; // arguments of the process
        boost::optional<Process::Environment> env;
        std::string cleanup_cmd;
    };
    typedef boost::shared_ptr<ProcessInfo> ProcessInfoPtr;

    std::list<ProcessInfoPtr> mProcesses;

    boost::thread mWatchdogThread;
    boost::mutex mMutex;

    typedef boost::function<void(const ProcessInfo& p)> RequiredProcessTerminatedFn;

    RequiredProcessTerminatedFn mRequiredProcessTerminatedFn;

public:
    ~ProcessSpawnManager()
    {
        mWatchdogThread.interrupt();
        mWatchdogThread.join();
    }

    void startProcess(const Path& executable, const std::vector<std::string>& args,
                      const std::string& name = "",
                      bool respawn=false, bool required=false,
                      bool shutdownRecursively=false,
                      boost::optional<Process::Environment> env = boost::optional<Process::Environment>(),
                      const std::string& cleanupCmd="")
    {
        ProcessInfoPtr info(new ProcessInfo);

        // store infos
        info->name = name;
        info->respawn = respawn;
        info->required = required;

        Process::CreationFlags flags = Process::interruptChildOnParentDeath;
        if (shutdownRecursively)
            flags |= Process::shutdownRecursively;

        // launch the new process
        info->process = Process::createProcess(executable.string(), args,
                                               flags,
                                               Process::none, env);
        info->pid = toString(info->process.getPID());

        info->shutdownRecursively = shutdownRecursively;
        info->executable = executable;
        info->args = args;
        info->env = env;
        info->cleanup_cmd = cleanupCmd;

        // synchronize
        {
            boost::mutex::scoped_lock lock(mMutex);
            mProcesses.push_back(info);
        }
    }

    void startWatchdog(RequiredProcessTerminatedFn fn = RequiredProcessTerminatedFn())
    {
        mRequiredProcessTerminatedFn = fn;
        // start watchdog thread that respawns processes when they terminate
        // if not yet running
        if(mWatchdogThread.get_id()==boost::thread::id())
            mWatchdogThread = boost::thread(&ProcessSpawnManager::watchdog, this);
    }

    void watchdog()
    {
        if(!ThreadMonitor::isDestroyed())
            ThreadMonitor::instance().addThisThread("#ProcessSpawnManager Watchdog");

        while(!boost::this_thread::interruption_requested()) {
            boost::this_thread::sleep(Duration::seconds(1));

            boost::mutex::scoped_lock lock(mMutex);
            foreach(ProcessInfoPtr info, mProcesses)
            {
                if(info->process.isRunning())
                    continue; // process is still running, nothing to do

                MIRA_LOG(NOTICE) << "Process '" << info->getName() << "' "
                                 << "was terminated.";
                // if we reach here, the process was stopped and we need
                // to respawn it or terminate ourselves
                if(info->respawn) {
                    Process::CreationFlags flags = Process::interruptChildOnParentDeath;
                    if (info->shutdownRecursively)
                        flags |= Process::shutdownRecursively;
                    MIRA_LOG(NOTICE) << "Respawning: " << info->getName();
                    info->process = Process::createProcess(info->executable.string(), info->args,
                                                           flags,
                                                           Process::none, info->env);
                    info->pid = toString(info->process.getPID());
                } else if(info->required) {
                    if(mRequiredProcessTerminatedFn)
                        mRequiredProcessTerminatedFn(*info);
                }
            }
        }
        if(!ThreadMonitor::isDestroyed())
            ThreadMonitor::instance().removeThisThread();
    }

};


} // namespace

#endif