RTMP在NGINX的启动

作者原创，转载请联系作者

本文主要介绍通过前文介绍的将rtmp模块编译进nginx情况下，启动nginx时rtmp模块主要做了哪些工作

Nginx的模块开发三段式

定义nginx模块需要定义三个变量：command，ctx，module。RTMP此三段式在rtmp.c文件中，模块参考代码如下：

static ngx_command_t  ngx_rtmp_commands[] = {
  { ngx_string("rtmp"),
    NGX_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_NOARGS,
    ngx_rtmp_block,
    0,
    0,
    NULL },
  ngx_null_command
};

static ngx_core_module_t  ngx_rtmp_module_ctx = {
  ngx_string("rtmp"),
  NULL,
  NULL
};

ngx_module_t  ngx_rtmp_module = {
  NGX_MODULE_V1,
  &ngx_rtmp_module_ctx,                  /* module context */
  ngx_rtmp_commands,                     /* module directives */
  NGX_CORE_MODULE,                       /* module type */
  NULL,                                  /* init master */
  NULL,                                  /* init module */
  ngx_rtmp_init_process,                 /* init process */
  NULL,                                  /* init thread */
  NULL,                                  /* exit thread */
  NULL,                                  /* exit process */
  NULL,                                  /* exit master */
  NGX_MODULE_V1_PADDING
};

RTMP模块如何启动？

RTMP模块的启动函数在ngx_rtmp_commands申明的ngx_rtmp_block()。下面主要讲解如何调用：

ngx_rtmp_commands的类型为ngx_command_t，其定义为：
struct ngx_command_s {
ngx_str_t name;
ngx_uint_t type;
char (set)(ngx_conf_t *cf, ngx_command_t cmd, voidconf);
ngx_uint_t conf;
ngx_uint_t offset;
void *post;
};
rtmp_block对应是set指针
set的是在nginx启动的时候，ngx_conf_handler()中调用，其简化代码如下。可以看出，其主要根据编译时生成的ngx_modules变量，以此取出module定义的command和ctx，调用command的set函数依次启动各个模块
for (i = 0; ngx_modules[i]; i++) {
cmd = ngx_modules[i]->commands;
for ( /* void / ; cmd->name.len; cmd++) {
/ set up the directive's configuration context */
conf = NULL;
if (cmd->type & NGX_DIRECT_CONF) {
conf = ((void **) cf->ctx)[ngx_modules[i]->index];
} else if (cmd->type & NGX_MAIN_CONF) {
conf = &(((void **) cf->ctx)[ngx_modules[i]->index]);
} else if (cf->ctx) {
confp = *(void **) ((char *) cf->ctx + cmd->conf);
if (confp) {
conf = confp[ngx_modules[i]->ctx_index];
}
}
rv = cmd->set(cf, cmd, conf);
}
}
调用链如下：
static ngx_int_t ngx_conf_handler(ngx_conf_t *cf, ngx_int_t last) ->
```
char * ngx_conf_parse(ngx_conf_t *cf, ngx_str_t *filename) ->

char * ngx_conf_param(ngx_conf_t *cf)  ->

ngx_cycle_t * ngx_init_cycle(ngx_cycle_t *old_cycle) ->

int ngx_cdecl  main(int argc, char *const *argv)
```
RTMP启动做了什么？
RTMP启动具体做了什么其实就是ngx_rtmp_block()的功能，此处简略说明：
1、计算RTMP模块数并设置每个模块的上下文索引
2、为每个RTMP模块创建main_conf
3、为每个RTMP模块创建srv_conf
4、为每个RTMP模块创建app_conf
5、调用各个RTMP模块preconfiguration
6、初始化各个RTMP模块 init_main_conf
7、初始化各个RTMP模块各个APP的merge_srv_conf
8、初始化各个RTMP模块各个APP的merge_app_conf
9、初始化各个RTMP服务事件

10、调用各个模块postconfiguration，主要是注册回调，具体如下

NGX_RTMP_CONNECT
注册模块：ngx_rtmp_limit_module
注册回调：ngx_rtmp_limit_connect;
NGX_RTMP_HANDSHAKE_DONE
注册模块：ngx_rtmp_relay_module中初始化
注册回调：ngx_rtmp_relay_handshake_done
NGX_RTMP_DISCONNECT
注册模块：ngx_rtmp_cmd_module
注册回调：ngx_rtmp_cmd_disconnect_init;
注册模块：ngx_rtmp_codec_module
注册回调：ngx_rtmp_codec_disconnect;
注册模块：ngx_rtmp_limit_module
注册回调：ngx_rtmp_limit_disconnect;
注册模块：ngx_rtmp_log_module
注册回调：ngx_rtmp_log_disconnect;
注册模块：ngx_rtmp_netcall_module
注册回调：ngx_rtmp_netcall_disconnect;
NGX_RTMP_MSG_AUDIO
注册模块：ngx_rtmp_codec_module
注册回调：ngx_rtmp_codec_av
注册模块：ngx_rtmp_dash_module
注册回调：ngx_rtmp_dash_video
注册模块：ngx_rtmp_hls_module
注册回调：ngx_rtmp_hls_audio
注册模块：ngx_rtmp_live_module
注册回调：ngx_rtmp_live_av
注册模块：ngx_rtmp_record_module
注册回调：ngx_rtmp_record_av
NGX_RTMP_MSG_VIDEO
注册模块：ngx_rtmp_codec_module
注册回调：ngx_rtmp_codec_av
注册模块：ngx_rtmp_dash_module
注册回调：ngx_rtmp_dash_video
注册模块：ngx_rtmp_hls_module
注册回调：ngx_rtmp_hls_audio
注册模块：ngx_rtmp_live_module
注册回调：ngx_rtmp_live_av
注册模块：ngx_rtmp_record_module
注册回调：ngx_rtmp_record_av

11、初始化事件处理，主要是AMF消息，特殊消息，处理回调注册

static size_t    pm_events[] = {
    NGX_RTMP_MSG_CHUNK_SIZE,
    NGX_RTMP_MSG_ABORT,
    NGX_RTMP_MSG_ACK,
    NGX_RTMP_MSG_ACK_SIZE,
    NGX_RTMP_MSG_BANDWIDTH
  };
  static size_t    amf_events[] = {
    NGX_RTMP_MSG_AMF_CMD,
    NGX_RTMP_MSG_AMF_META,
    NGX_RTMP_MSG_AMF_SHARED,
    NGX_RTMP_MSG_AMF3_CMD,
    NGX_RTMP_MSG_AMF3_META,
    NGX_RTMP_MSG_AMF3_SHARED
  };
  /* init standard protocol events */
  for(n = 0; n < sizeof(pm_events) / sizeof(pm_events[0]); ++n) {
    eh = ngx_array_push(&cmcf->events[pm_events[n]]);
    *eh = ngx_rtmp_protocol_message_handler;
  }

  /* init amf events */
  for(n = 0; n < sizeof(amf_events) / sizeof(amf_events[0]); ++n) {
    eh = ngx_array_push(&cmcf->events[amf_events[n]]);
    *eh = ngx_rtmp_amf_message_handler;
  }

  /* init user protocol events */
  eh = ngx_array_push(&cmcf->events[NGX_RTMP_MSG_USER]);
  *eh = ngx_rtmp_user_message_handler;

  /* aggregate to audio/video map */
  eh = ngx_array_push(&cmcf->events[NGX_RTMP_MSG_AGGREGATE]);
  *eh = ngx_rtmp_aggregate_message_handler;

特别需要提出的是在ngx_rtmp_cmd_module模块，对相应的用户控制消息进行注册，代码如下：

static ngx_rtmp_amf_handler_t ngx_rtmp_cmd_map[] = {
{ ngx_string("connect"),            ngx_rtmp_cmd_connect_init           },
{ ngx_string("createStream"),       ngx_rtmp_cmd_create_stream_init     },
{ ngx_string("closeStream"),        ngx_rtmp_cmd_close_stream_init      },
{ ngx_string("deleteStream"),       ngx_rtmp_cmd_delete_stream_init     },
{ ngx_string("publish"),            ngx_rtmp_cmd_publish_init           },
{ ngx_string("play"),               ngx_rtmp_cmd_play_init              },
{ ngx_string("play2"),              ngx_rtmp_cmd_play2_init             },
{ ngx_string("seek"),               ngx_rtmp_cmd_seek_init              },
{ ngx_string("pause"),              ngx_rtmp_cmd_pause_init             },
{ ngx_string("pauseraw"),           ngx_rtmp_cmd_pause_init             },
};

......
ncalls = sizeof(ngx_rtmp_cmd_map) /  sizeof(ngx_rtmp_cmd_map[0]);
ch = ngx_array_push_n(&cmcf->amf, ncalls);
bh = ngx_rtmp_cmd_map;
for(n = 0; n < ncalls; ++n, ++ch, ++bh) {
    *ch = *bh;
}
......

12、开始各个RTMP服务侦听，注册连接到时时执行ngx_rtmp_init_connection的回调

RTMP在NGINX的启动

Nginx的模块开发三段式

RTMP模块如何启动？

你可能感兴趣的:(RTMP在NGINX的启动)