srs/trunk/src/app/srs_app_process.hpp

/*
 The MIT License (MIT)
 
 Copyright (c) 2013-2015 SRS(simple-rtmp-server)
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of
 this software and associated documentation files (the "Software"), to deal in
 the Software without restriction, including without limitation the rights to
 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 the Software, and to permit persons to whom the Software is furnished to do so,
 subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef SRS_APP_PROCESS_HPP
#define SRS_APP_PROCESS_HPP

/*
#include <srs_app_process.hpp>
*/
#include <srs_core.hpp>

#include <string>
#include <vector>

/**
 * to start and stop a process, cycle to restart the process when terminated.
 * the usage:
 *      // the binary is the process to fork.
 *      binary = "./objs/ffmpeg/bin/ffmpeg";
 *      // where argv is a array contains each params.
 *      argv = ["-i", "in.flv", "1", ">", "/dev/null", "2", ">", "/dev/null"];
 *
 *      process = new SrsProcess();
 *      if ((ret = process->initialize(binary, argv)) != ERROR_SUCCESS) { return ret; }
 *      if ((ret = process->start()) != ERROR_SUCCESS) { return ret; }
 *      if ((ret = process->cycle()) != ERROR_SUCCESS) { return ret; }
 *      process->fast_stop();
 *      process->stop();
 */
class SrsProcess
{
private:
    bool is_started;
    // whether SIGTERM send but need to wait or SIGKILL.
    bool fast_stopped;
    pid_t pid;
private:
    std::string bin;
    std::string stdout_file;
    std::string stderr_file;
    std::vector<std::string> params;
    // the cli to fork process.
    std::string cli;
public:
    SrsProcess();
    virtual ~SrsProcess();
public:
    /**
     * whether process is already started.
     */
    virtual bool started();
    /**
     * initialize the process with binary and argv.
     */
    virtual int initialize(std::string binary, std::vector<std::string> argv);
public:
    /**
     * start the process, ignore when already started.
     */
    virtual int start();
    /**
     * cycle check the process, update the state of process.
     * @remark when process terminated(not started), user can restart it again by start().
     */
    virtual int cycle();
    /**
     * send SIGTERM then SIGKILL to ensure the process stopped.
     * the stop will wait [0, SRS_PROCESS_QUIT_TIMEOUT_MS] depends on the
     * process quit timeout.
     * @remark use fast_stop before stop one by one, when got lots of process to quit.
     */
    virtual void stop();
public:
    /**
     * the fast stop is to send a SIGTERM.
     * for example, the ingesters owner lots of FFMPEG, it will take a long time
     * to stop one by one, instead the ingesters can fast_stop all FFMPEG, then
     * wait one by one to stop, it's more faster.
     * @remark user must use stop() to ensure the ffmpeg to stopped.
     * @remark we got N processes to stop, compare the time we spend,
     *      when use stop without fast_stop, we spend maybe [0, SRS_PROCESS_QUIT_TIMEOUT_MS * N]
     *      but use fast_stop then stop, the time is almost [0, SRS_PROCESS_QUIT_TIMEOUT_MS].
     */
    virtual void fast_stop();
};

#endif