SRS启动流程

main函数

main函数所在文件为main/srs_main_server.cpp中。

该文件定义了一些全局变量：

• _srs_log:全局的log文件
• _srs_context:全局的context文件。是一个SrsThreadContext类，这个类使用map来存放协程指针到id的映射关系。std::map

cache;

• _srs_config:全局配置文件

run_master

程序进入run_master。在该函数中，服务器做一些初始化工作并调用listern监听客户端的连接，然后调用do_cycle函数(死循环)，做一些监控，更新时间及缓存等。

执行流程如图：

代码分析如下：

//run()调用run_master()，启动 srs_error_t run_master(SrsServer* svr) { srs_error_t err = srs_success; //初始化st if ((err = svr->initialize_st()) != srs_success) { return srs_error_wrap(err, "initialize st"); } //初始化signal:创建signal pipe if ((err = svr->initialize_signal()) != srs_success) { return srs_error_wrap(err, "initialize signal"); } //将pid线程写进文件 if ((err = svr->acquire_pid_file()) != srs_success) { return srs_error_wrap(err, "acquire pid file"); } //监听客户端请求 if ((err = svr->listen()) != srs_success) { return srs_error_wrap(err, "listen"); } //注册信号(开启了新的协程) if ((err = svr->register_signal()) != srs_success) { return srs_error_wrap(err, "register signal"); } //undo if ((err = svr->http_handle()) != srs_success) { return srs_error_wrap(err, "http handle"); } //undo if ((err = svr->ingest()) != srs_success) { return srs_error_wrap(err, "ingest"); } //服务器的循环 if ((err = svr->cycle()) != srs_success) { return srs_error_wrap(err, "main cycle"); } return err; } 

do_cycle

srs_error_t SrsServer::do_cycle() { srs_error_t err = srs_success; // find the max loop int max = srs_max(0, SRS_SYS_TIME_RESOLUTION_MS_TIMES); #ifdef SRS_AUTO_STAT max = srs_max(max, SRS_SYS_RUSAGE_RESOLUTION_TIMES); max = srs_max(max, SRS_SYS_CPU_STAT_RESOLUTION_TIMES); max = srs_max(max, SRS_SYS_DISK_STAT_RESOLUTION_TIMES); max = srs_max(max, SRS_SYS_MEMINFO_RESOLUTION_TIMES); max = srs_max(max, SRS_SYS_PLATFORM_INFO_RESOLUTION_TIMES); max = srs_max(max, SRS_SYS_NETWORK_DEVICE_RESOLUTION_TIMES); max = srs_max(max, SRS_SYS_NETWORK_RTMP_SERVER_RESOLUTION_TIMES); #endif // for asprocess. bool asprocess = _srs_config->get_asprocess(); // the deamon thread, update the time cache while (true) { //这里handle为NULL if (handler && (err = handler->on_cycle()) != srs_success) { return srs_error_wrap(err, "handle callback"); } // the interval in config. default=9.9 int heartbeat_max_resolution = (int)(_srs_config->get_heartbeat_interval() / SRS_SYS_CYCLE_INTERVAL); // dynamic fetch the max. 1 int dynamic_max = srs_max(max, heartbeat_max_resolution); for (int i = 0; i < dynamic_max; i++) { //主线程休眠，让出CPU，其他线程如conn接受连接 srs_usleep(SRS_SYS_CYCLE_INTERVAL * 1000); //1000 * 1000, 1s // asprocess check. if (asprocess && ::getppid() != ppid) { return srs_error_new(ERROR_ASPROCESS_PPID, "asprocess ppid changed from %d to %d", ppid, ::getppid()); } // gracefully quit for SIGINT or SIGTERM. 收到腿出信号，返回 if (signal_gracefully_quit) { srs_trace("cleanup for gracefully terminate."); return err; } // for gperf heap checker, // @see: research/gperftools/heap-checker/heap_checker.cc // if user interrupt the program, exit to check mem leak. // but, if gperf, use reload to ensure main return normally, // because directly exit will cause core-dump. #ifdef SRS_AUTO_GPERF_MC if (signal_gmc_stop) { srs_warn("gmc got singal to stop server."); return err; } #endif // do persistence config to file. if (signal_persistence_config) { signal_persistence_config = false; srs_info("get signal to persistence config to file."); if ((err = _srs_config->persistence()) != srs_success) { return srs_error_wrap(err, "config persistence to file"); } srs_trace("persistence config to file success."); } // do reload the config. 重新加载配置的信号 if (signal_reload) { signal_reload = false; srs_info("get signal to reload the config."); if ((err = _srs_config->reload()) != srs_success) { return srs_error_wrap(err, "config reload"); } srs_trace("reload config success."); } // notice the stream sources to cycle. 流资源循环 if ((err = SrsSource::cycle_all()) != srs_success) { return srs_error_wrap(err, "source cycle"); } // update the cache time 事件缓存 if ((i % SRS_SYS_TIME_RESOLUTION_MS_TIMES) == 0) { srs_info("update current time cache."); srs_update_system_time_ms(); } #ifdef SRS_AUTO_STAT if ((i % SRS_SYS_RUSAGE_RESOLUTION_TIMES) == 0) { srs_info("update resource info, rss."); srs_update_system_rusage(); } if ((i % SRS_SYS_CPU_STAT_RESOLUTION_TIMES) == 0) { srs_info("update cpu info, cpu usage."); srs_update_proc_stat(); } if ((i % SRS_SYS_DISK_STAT_RESOLUTION_TIMES) == 0) { srs_info("update disk info, disk iops."); srs_update_disk_stat(); } if ((i % SRS_SYS_MEMINFO_RESOLUTION_TIMES) == 0) { srs_info("update memory info, usage/free."); srs_update_meminfo(); } if ((i % SRS_SYS_PLATFORM_INFO_RESOLUTION_TIMES) == 0) { srs_info("update platform info, uptime/load."); srs_update_platform_info(); } if ((i % SRS_SYS_NETWORK_DEVICE_RESOLUTION_TIMES) == 0) { srs_info("update network devices info."); srs_update_network_devices(); } if ((i % SRS_SYS_NETWORK_RTMP_SERVER_RESOLUTION_TIMES) == 0) { srs_info("update network server kbps info."); resample_kbps(); } if (_srs_config->get_heartbeat_enabled()) { if ((i % heartbeat_max_resolution) == 0) { srs_info("do http heartbeat, for internal server to report."); http_heartbeat->heartbeat(); } } #endif srs_info("server main thread loop"); } } return err; }