标签：write accept sprint bst led tco oid actual 连接数
http://nginx.org/en/docs/http/ngx_http_stub_status_module.html
ngx_http_stub_status_module 是一个 Nginx 的内置 HTTP 模块，该模块可以提供 Nginx 的状态信息。默认情况下这个模块是不被编译进来的，所以在编译 Nginx 时要指定加载该模块：
--with-http_stub_status_module为什么拿它做例子？因为它也是个足够短小精悍的模块，是一个典型 handler 模块。那么以后我们讲解模块的过程，都是：
location /nginx_status {
stub_status on;
access_log off;
access_log /usr/local/nginx/logs/status.log; #日志
allow SOME.IP.ADD.RESS;
deny all;
}
我们假设你是在本机上实验，并且开启的是 80 端口，那么在浏览器中输入：
http://localhost/nginx_status
会看到这样的信息：
Active connections: 291
server accepts handled requests
16630948 16630948 31070465
Reading: 6 Writing: 179 Waiting: 106
其含义很容易理解：
- 当前的活跃连接数：291
- 服务器已接受的连接数：16630948（accepted connection #）
- 服务器已处理的连接数：16630948（handled connection #）
- 服务器已处理的请求：31070465（可以算出，平均每个连接有 1.8 个请求）（handled connection #）
- Reading – Nginx 读取的请求头次数为 6；
- Writting – Nginx 读取请求体、处理请求并发送响应给客户端的次数为 179；
- Waiting – 当前活动的长连接数：106。
Nginx 官方的解释如下：
active connections – number of all open connectionsserver accepts handled requests – nginx accepted 16630948 connections, handled 16630948 connections (no one was closed just it was accepted), and handles 31070465 requests (1.8 requests per connection)reading – nginx reads request headerwriting – nginx reads request body, processes request, or writes response to a clientwaiting – keep-alive connections, actually it is active - (reading + writing)这个模块中的唯一一个指令，是：
stub_status
stub_status on先看完整代码：
/*
* Copyright (C) Igor Sysoev
* Copyright (C) Nginx, Inc.
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
static char *ngx_http_set_status(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
static ngx_command_t ngx_http_status_commands[] = {
{ ngx_string("stub_status"),
NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
ngx_http_set_status,
0,
0,
NULL },
ngx_null_command
};
static ngx_http_module_t ngx_http_stub_status_module_ctx = {
NULL, /* preconfiguration */
NULL, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
NULL, /* create server configuration */
NULL, /* merge server configuration */
NULL, /* create location configuration */
NULL /* merge location configuration */
};
ngx_module_t ngx_http_stub_status_module = {
NGX_MODULE_V1,
&ngx_http_stub_status_module_ctx, /* module context */
ngx_http_status_commands, /* module directives */
NGX_HTTP_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
};
static ngx_int_t ngx_http_status_handler(ngx_http_request_t *r)
{
size_t size;
ngx_int_t rc;
ngx_buf_t *b;
ngx_chain_t out;
ngx_atomic_int_t ap, hn, ac, rq, rd, wr;
if (r->method != NGX_HTTP_GET && r->method != NGX_HTTP_HEAD) {
return NGX_HTTP_NOT_ALLOWED;
}
rc = ngx_http_discard_request_body(r);
if (rc != NGX_OK) {
return rc;
}
ngx_str_set(&r->headers_out.content_type, "text/plain");
if (r->method == NGX_HTTP_HEAD) {
r->headers_out.status = NGX_HTTP_OK;
rc = ngx_http_send_header(r);
if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
return rc;
}
}
size = sizeof("Active connections: \n") + NGX_ATOMIC_T_LEN
+ sizeof("server accepts handled requests\n") - 1
+ 6 + 3 * NGX_ATOMIC_T_LEN
+ sizeof("Reading: Writing: Waiting: \n") + 3 * NGX_ATOMIC_T_LEN;
b = ngx_create_temp_buf(r->pool, size);
if (b == NULL) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
out.buf = b;
out.next = NULL;
ap = *ngx_stat_accepted;
hn = *ngx_stat_handled;
ac = *ngx_stat_active;
rq = *ngx_stat_requests;
rd = *ngx_stat_reading;
wr = *ngx_stat_writing;
b->last = ngx_sprintf(b->last, "Active connections: %uA \n", ac);
b->last = ngx_cpymem(b->last, "server accepts handled requests\n",
sizeof("server accepts handled requests\n") - 1);
b->last = ngx_sprintf(b->last, " %uA %uA %uA \n", ap, hn, rq);
b->last = ngx_sprintf(b->last, "Reading: %uA Writing: %uA Waiting: %uA \n",
rd, wr, ac - (rd + wr));
r->headers_out.status = NGX_HTTP_OK;
r->headers_out.content_length_n = b->last - b->pos;
b->last_buf = 1;
rc = ngx_http_send_header(r);
if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
return rc;
}
return ngx_http_output_filter(r, &out);
}
static char *ngx_http_set_status(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
ngx_http_core_loc_conf_t *clcf;
clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
clcf->handler = ngx_http_status_handler;
return NGX_CONF_OK;
}
的确够短小精悍吧？关键在于 Nginx 提供的模块扩展方式比较好，让你可以少写一些代码（NDK 可以让你写的更少，这是后话）。
ngx_module_t ngx_http_stub_status_module = {
NGX_MODULE_V1,
&ngx_http_stub_status_module_ctx, /* module context */
ngx_http_status_commands, /* module directives */
NGX_HTTP_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
};
与此前介绍的 ngx_http_hello_world_module 并无本质区别。
static ngx_command_t ngx_http_status_commands[] = {
{ ngx_string("stub_status"),
NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
ngx_http_set_status,
0,
0,
NULL },
ngx_null_command
};
命令集定义如上，得到如下信息：
#define NGX_CONF_ARGS_NUMBER 0x000000ff#define NGX_CONF_BLOCK 0x00000100#define NGX_CONF_FLAG 0x00000200#define NGX_CONF_ANY 0x00000400#define NGX_CONF_1MORE 0x00000800#define NGX_CONF_2MORE 0x00001000#define NGX_CONF_MULTI 0x00002000
下面解释下一些 types：
以下宏定义来自 ngx_conf_file.h：
#define NGX_CONF_NOARGS 0x00000001 // 命令不接受参数
#define NGX_CONF_TAKE1 0x00000002 // 命令携带1个参数
#define NGX_CONF_TAKE2 0x00000004 // 命令携带2个参数
#define NGX_CONF_TAKE3 0x00000008 // 命令携带3个参数
#define NGX_CONF_TAKE4 0x00000010 // 命令携带4个参数
#define NGX_CONF_TAKE5 0x00000020 // 命令携带5个参数
#define NGX_CONF_TAKE6 0x00000040 // 命令携带6个参数
#define NGX_CONF_TAKE7 0x00000080 // 命令携带7个参数
#define NGX_CONF_TAKE12 (NGX_CONF_TAKE1|NGX_CONF_TAKE2) // 命令携带1个或2个参数
#define NGX_CONF_TAKE13 (NGX_CONF_TAKE1|NGX_CONF_TAKE3) // 命令携带1个或3个参数
#define NGX_CONF_TAKE23 (NGX_CONF_TAKE2|NGX_CONF_TAKE3) // 命令携带2个或3个参数
#define NGX_CONF_TAKE123 (NGX_CONF_TAKE1|NGX_CONF_TAKE2|NGX_CONF_TAKE3) // 命令携带1个、2个或3个参数
#define NGX_CONF_TAKE1234 (NGX_CONF_TAKE1|NGX_CONF_TAKE2|NGX_CONF_TAKE3|NGX_CONF_TAKE4) // 命令携带1个、2个、3个或4个参数
#define NGX_CONF_ARGS_NUMBER 0x000000ff // 命令
#define NGX_CONF_BLOCK 0x00000100 // 块域，后面跟 {…}，比如 server {...}
#define NGX_CONF_FLAG 0x00000200 // 命令接受“on|off”参数
#define NGX_CONF_ANY 0x00000400
#define NGX_CONF_1MORE 0x00000800 // 命令携带至少1个参数
#define NGX_CONF_2MORE 0x00001000 // 命令携带至少2个参数
#define NGX_CONF_MULTI 0x00002000 // 命令携带多个参数
static ngx_http_module_t ngx_http_stub_status_module_ctx = {
NULL, /* preconfiguration */
NULL, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
NULL, /* create server configuration */
NULL, /* merge server configuration */
NULL, /* create location configuration */
NULL /* merge location configuration */
};
这个都是 NULL，够简单，无话可说了??
static char *ngx_http_set_status(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) {
ngx_http_core_loc_conf_t *clcf;
clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
clcf->handler = ngx_http_status_handler;
return NGX_CONF_OK;
}
和 ngx_http_hello_world_module 对比下：
static char* ngx_http_hello_world(ngx_conf_t* cf, ngx_command_t* cmd, void* conf) {
ngx_http_core_loc_conf_t* clcf;
clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
clcf->handler = ngx_http_hello_world_handler;
ngx_conf_set_str_slot(cf, cmd, conf);
return NGX_CONF_OK;
}
唯一的区别，就是 ngx_http_hello_world_module 多了一句 ngx_conf_set_str_slot。这个先留做一个问题，后面会介绍，暂时与关键主题无关。
static ngx_int_t ngx_http_status_handler(ngx_http_request_t *r)
{
size_t size;
ngx_int_t rc;
ngx_buf_t *b;
ngx_chain_t out;
ngx_atomic_int_t ap, hn, ac, rq, rd, wr;
这个模块要求接受的请求类是 GET、HEAD，其他类型的请求会被拒绝。
if (r->method != NGX_HTTP_GET && r->method != NGX_HTTP_HEAD) {
return NGX_HTTP_NOT_ALLOWED;
}
放弃请求体，因为这个模块用不上。
rc = ngx_http_discard_request_body(r);
if (rc != NGX_OK) {
return rc;
}
如果请求是 HEAD 类型的，则直接设置响应头的 content_type、status 字段，并发送响应头。
ngx_str_set(&r->headers_out.content_type, "text/plain");
if (r->method == NGX_HTTP_HEAD) {
r->headers_out.status = NGX_HTTP_OK;
rc = ngx_http_send_header(r);
if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
return rc;
}
}
创建一个缓冲区，向缓冲区写入我们上面在浏览器中看到的东西。
size = sizeof("Active connections: \n") + NGX_ATOMIC_T_LEN
+ sizeof("server accepts handled requests\n") - 1
+ 6 + 3 * NGX_ATOMIC_T_LEN
+ sizeof("Reading: Writing: Waiting: \n") + 3 * NGX_ATOMIC_T_LEN;
b = ngx_create_temp_buf(r->pool, size);
if (b == NULL) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
out.buf = b;
out.next = NULL;
ap = *ngx_stat_accepted;
hn = *ngx_stat_handled;
ac = *ngx_stat_active;
rq = *ngx_stat_requests;
rd = *ngx_stat_reading;
wr = *ngx_stat_writing;
// 封装了 sprintf
b->last = ngx_sprintf(b->last, "Active connections: %uA \n", ac);
// 封装了 memcpy
b->last = ngx_cpymem(b->last, "server accepts handled requests\n",
sizeof("server accepts handled requests\n") - 1);
b->last = ngx_sprintf(b->last, " %uA %uA %uA \n", ap, hn, rq);
b->last = ngx_sprintf(b->last, "Reading: %uA Writing: %uA Waiting: %uA \n",
rd, wr, ac - (rd + wr));
缓冲区写完了。然后设置下响应头的 status、content_length_n（还记得吗？b->last - b->pos 刚好是缓冲区的第二个区域，是已写入数据部分。）
r->headers_out.status = NGX_HTTP_OK;
r->headers_out.content_length_n = b->last - b->pos;
b->last_buf = 1;
发送响应头。
rc = ngx_http_send_header(r);
if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
return rc;
}
filter。
return ngx_http_output_filter(r, &out);
}
Nginx解读内置非默认模块 ngx_http_stub_status_module
标签：write accept sprint bst led tco oid actual 连接数
原文地址：https://www.cnblogs.com/felixzh/p/9016133.html
