分析Nginx，从最基础的角度出发，也就是事件驱动开始
首先是事件的的定义
//定义事件
typedef struct {
ngx_int_t (*add)(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags);
ngx_int_t (*del)(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags);
ngx_int_t (*enable)(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags);
ngx_int_t (*disable)(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags);
ngx_int_t (*add_conn)(ngx_connection_t *c);
ngx_int_t (*del_conn)(ngx_connection_t *c, ngx_uint_t flags);
ngx_int_t (*notify)(ngx_event_handler_pt handler);
ngx_int_t (*process_events)(ngx_cycle_t *cycle, ngx_msec_t timer,
ngx_uint_t flags);
ngx_int_t (*init)(ngx_cycle_t *cycle, ngx_msec_t timer);
void (*done)(ngx_cycle_t *cycle);
} ngx_event_actions_t;
-----------------------
ngx_event_actions_t ngx_event_actions;
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// 定义每个事件的宏
#define ngx_process_events ngx_event_actions.process_events
#define ngx_done_events ngx_event_actions.done
#define ngx_add_event ngx_event_actions.add
#define ngx_del_event ngx_event_actions.del
#define ngx_add_conn ngx_event_actions.add_conn
#define ngx_del_conn ngx_event_actions.del_conn
#define ngx_notify ngx_event_actions.notify
#define ngx_add_timer ngx_event_add_timer
#define ngx_del_timer ngx_event_del_timer
//事件具体操作的逻辑放入到此处
static ngx_event_module_t ngx_epoll_module_ctx = {
&epoll_name,
ngx_epoll_create_conf, /* create configuration */
ngx_epoll_init_conf, /* init configuration */
{
ngx_epoll_add_event, /* add an event */
ngx_epoll_del_event, /* delete an event */
ngx_epoll_add_event, /* enable an event */
ngx_epoll_del_event, /* disable an event */
ngx_epoll_add_connection, /* add an connection */
ngx_epoll_del_connection, /* delete an connection */
#if (NGX_HAVE_EVENTFD)
ngx_epoll_notify, /* trigger a notify */
#else
NULL, /* trigger a notify */
#endif
ngx_epoll_process_events, /* process the events */
ngx_epoll_init, /* init the events */
ngx_epoll_done, /* done the events */
}
};
ngx_event_module_t是新定义的结构
typedef struct {
//事件模块名称
ngx_str_t *name;
void *(*create_conf)(ngx_cycle_t *cycle);
char *(*init_conf)(ngx_cycle_t *cycle, void *conf);
//事件模块，每个事件模块需要实现10个抽象方法
ngx_event_actions_t actions;
} ngx_event_module_t;
//创建epoll的内存结构从内存池中
static void *
ngx_epoll_create_conf(ngx_cycle_t *cycle)
{
ngx_epoll_conf_t *epcf;
epcf = ngx_palloc(cycle->pool, sizeof(ngx_epoll_conf_t));
if (epcf == NULL) {
return NULL;
}
epcf->events = NGX_CONF_UNSET;
epcf->aio_requests = NGX_CONF_UNSET;
return epcf;
}
//初始化事件的信息
static char *
ngx_epoll_init_conf(ngx_cycle_t *cycle, void *conf)
{
ngx_epoll_conf_t *epcf = conf;
ngx_conf_init_uint_value(epcf->events, 512);
ngx_conf_init_uint_value(epcf->aio_requests, 32);
return NGX_CONF_OK;
}
Nginx连接的定义
//被动连接，指的是客户端连接，服务器被动接收
struct ngx_connection_s {
void *data;
ngx_event_t *read;
ngx_event_t *write;
ngx_socket_t fd;
ngx_recv_pt recv;
ngx_send_pt send;
ngx_recv_chain_pt recv_chain;
ngx_send_chain_pt send_chain;
ngx_listening_t *listening;
off_t sent;
ngx_log_t *log;
//定义pool的目的是新建的连接从连接池中获取
ngx_pool_t *pool;
int type;
struct sockaddr *sockaddr;
socklen_t socklen;
ngx_str_t addr_text;
ngx_str_t proxy_protocol_addr;
in_port_t proxy_protocol_port;
#if (NGX_SSL || NGX_COMPAT)
ngx_ssl_connection_t *ssl;
#endif
struct sockaddr *local_sockaddr;
socklen_t local_socklen;
ngx_buf_t *buffer;
ngx_queue_t queue;
ngx_atomic_uint_t number;
ngx_uint_t requests;
unsigned buffered:8;
unsigned log_error:3; /* ngx_connection_log_error_e */
unsigned timedout:1;
unsigned error:1;
unsigned destroyed:1;
unsigned idle:1;
unsigned reusable:1;
unsigned close:1;
unsigned shared:1;
unsigned sendfile:1;
unsigned sndlowat:1;
unsigned tcp_nodelay:2; /* ngx_connection_tcp_nodelay_e */
unsigned tcp_nopush:2; /* ngx_connection_tcp_nopush_e */
unsigned need_last_buf:1;
#if (NGX_HAVE_AIO_SENDFILE || NGX_COMPAT)
unsigned busy_count:2;
#endif
#if (NGX_THREADS || NGX_COMPAT)
ngx_thread_task_t *sendfile_task;
#endif
};
//作为web服务器，Nginx主动连接上游服务器，使用的是另外一个结构体
struct ngx_peer_connection_s {
ngx_connection_t *connection;
struct sockaddr *sockaddr;
socklen_t socklen;
ngx_str_t *name;
ngx_uint_t tries;
ngx_msec_t start_time;
ngx_event_get_peer_pt get;
ngx_event_free_peer_pt free;
ngx_event_notify_peer_pt notify;
void *data;
#if (NGX_SSL || NGX_COMPAT)
ngx_event_set_peer_session_pt set_session;
ngx_event_save_peer_session_pt save_session;
#endif
ngx_addr_t *local;
int type;
int rcvbuf;
ngx_log_t *log;
unsigned cached:1;
unsigned transparent:1;
/* ngx_connection_log_error_e */
unsigned log_error:2;
NGX_COMPAT_BEGIN(2)
NGX_COMPAT_END
};
ngx_events_module 核心模块
我们知道Nginx最核心的代码就是模块，每个模块组装成整个框架
/* 定义事件核心模块 */
ngx_module_t ngx_events_module = {
NGX_MODULE_V1,
&ngx_events_module_ctx, /* module context */
ngx_events_commands, /* module directives */
NGX_CORE_MODULE, /* module type */
NULL, /* init master */
NULL, /* init module */
NULL, /* init process */
NULL, /* init thread */
NULL, /* exit thread */
NULL, /* exit process */
NULL, /* exit master */
NGX_MODULE_V1_PADDING
};
ngx_events_commands为配置项指令结构
/* 配置项结构体数组 */
static ngx_command_t ngx_events_commands[] = {
{ ngx_string("events"),
NGX_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_NOARGS,
ngx_events_block,
0,
0,
NULL },
ngx_null_command
};