Nginx之Keepalive请求长连接复用率统计

该模块的实现原理比较简单：在NGX_LOG_PHASE阶段加入一个handler，根据请求是否upstream，再结合upstream->peer.cached参数即可判断该请求是否复用长连接。

#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
#include <nginx.h>
#include <ngx_files.h>

#define KEEPALIVE_LOG_DEBUG
#define KEEPALIVE_LOG_DEBUG_LEVEL NGX_LOG_NOTICE
#define KEEPALIVE_LOG_MAX_LOG_LEN 1024

typedef struct {
 ngx_log_t *default_log;
}ngx_http_keepalive_log_main_conf_t;

typedef struct {
 ngx_flag_t on;
 ngx_log_t *log;
} ngx_http_keepalive_log_loc_conf_t;

static void* ngx_http_keepalive_log_create_main_conf(ngx_conf_t *cf);
static void* ngx_http_keepalive_log_create_loc_conf(ngx_conf_t *cf);
static char* ngx_http_keepalive_log_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child);
static ngx_int_t ngx_http_keepalive_log_init(ngx_conf_t *cf);
static ngx_int_t ngx_http_keepalive_log_init_process(ngx_cycle_t *cycle);
static ngx_int_t ngx_http_keepalive_log_handler(ngx_http_request_t *r);
static void ngx_http_keepalive_log_get_req_info(ngx_http_request_t *r, ngx_str_t *serv, ngx_str_t *hostname, ngx_str_t *ip);
static ngx_log_t *ngx_log_create(ngx_cycle_t *cycle, ngx_str_t *name);
static char* ngx_http_keepalive_log_set_log(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);

static ngx_http_module_t ngx_http_keepalive_log_module_ctx = {
    NULL,
    ngx_http_keepalive_log_init,    /* postconfiguration */
   
 ngx_http_keepalive_log_create_main_conf,  /* create main configuration */
    NULL,

NULL,
    NULL,

ngx_http_keepalive_log_create_loc_conf,
    ngx_http_keepalive_log_merge_loc_conf   
};

static ngx_command_t ngx_http_keepalive_log_commands[] = {
 {
  ngx_string("keepalive_log"),
  NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF | NGX_HTTP_LIF_CONF | NGX_CONF_TAKE1,
  ngx_http_keepalive_log_set_log,
  NGX_HTTP_LOC_CONF_OFFSET,
  0,
  NULL
 },
 {
  ngx_string("keepalive_log_enable"),
  NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF | NGX_CONF_TAKE1,
  ngx_conf_set_flag_slot,
  NGX_HTTP_LOC_CONF_OFFSET,
        offsetof(ngx_http_keepalive_log_loc_conf_t, on),
  NULL
 },
 ngx_null_command
};

ngx_module_t ngx_http_keepalive_log_module = {
 NGX_MODULE_V1,
 &ngx_http_keepalive_log_module_ctx,
 ngx_http_keepalive_log_commands,
 NGX_HTTP_MODULE,
 NULL,              /* init master */
 NULL,              /* init module */
 ngx_http_keepalive_log_init_process,      /* init process */
 NULL,              /* init thread */
 NULL,              /* exit thread */
 NULL,              /* exit process */
 NULL,              /* exit master */
 NGX_MODULE_V1_PADDING
};

static ngx_int_t
ngx_http_keepalive_log_init_process(ngx_cycle_t *cycle)
{
 ngx_http_keepalive_log_main_conf_t *kmcf = ngx_http_cycle_get_module_main_conf(cycle, ngx_http_keepalive_log_module);
 kmcf->default_log = &cycle->new_log;

return NGX_OK;
}

static void*
ngx_http_keepalive_log_create_main_conf(ngx_conf_t *cf)
{
 ngx_http_keepalive_log_main_conf_t *kmcf;
 kmcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_keepalive_log_main_conf_t));
 if(!kmcf) {
  return NGX_CONF_ERROR;
 }
 kmcf->default_log = NULL;

return kmcf;
}

static void*
ngx_http_keepalive_log_create_loc_conf(ngx_conf_t *cf)
{
 ngx_http_keepalive_log_loc_conf_t *klcf;

klcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_keepalive_log_loc_conf_t));
 if(klcf == NULL) {
  return NULL;
 }

klcf->on = NGX_CONF_UNSET;
 klcf->log = NGX_CONF_UNSET_PTR;
   
    return klcf;
}

static char*
ngx_http_keepalive_log_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
{
 ngx_http_keepalive_log_loc_conf_t *prev = parent;
 ngx_http_keepalive_log_loc_conf_t *conf = child;

ngx_conf_merge_value(conf->on, prev->on, 0);
 ngx_conf_merge_ptr_value(conf->log, prev->log, NULL);

return NGX_CONF_OK;
}

static ngx_int_t
ngx_http_keepalive_log_init(ngx_conf_t *cf)
{
 ngx_http_handler_pt *h;
 ngx_http_core_main_conf_t *cmcf;