g-wan - How to disable G-WAN servlet internal cache?

Question

gwan version: 3.12.26

servlet type: C and Perl

problem:

gwan internal cache make request not re-read the script

test:

1. create 'log' dir :

   [bash]# mkdir -p /dev/shm/random-c
   [bash]# chmod 777 /dev/shm/random-c
   

2. create /path/to/gwan/0.0.0.0_8080/#0.0.0.0/csp/random.c

   // ============================================================================
   // C servlet sample for the G-WAN Web Application Server (http://trustleap.ch/)
   // ----------------------------------------------------------------------------
   // hello.c: just used with Lighty's Weighttp to benchmark a minimalist servlet
   // ============================================================================
   // imported functions:
   //   get_reply(): get a pointer on the 'reply' dynamic buffer from the server
   //    xbuf_cat(): like strcat(), but it works in the specified dynamic buffer
   // ----------------------------------------------------------------------------
   #include <sys/time.h>
   #include "gwan.h" // G-WAN exported functions
   #include <stdio.h>
   #include <stdlib.h>
   #include <string.h>
   
   
   //------------------
   void init_random(){
       struct /*sys/time.h->*/timeval res;
       /*sys/time.h->*/gettimeofday(&res,NULL);
      /*stdlib.h->*/srand( (unsigned int)/*stdlib.h->*/time(NULL) + res.tv_usec);
   }
   
   //------------------
   char *get_rnd_char(int num){
       char *char_list = "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
       int  char_list_len = 62;
       char *ret = (char *)/*stdlib.h->*/malloc((num * sizeof(char)) + 1);
       int i,r;
   
   
       for(i=0;i<num;i++){
           r=(int) (/*stdlib.h->*/rand() % char_list_len);
           ret[i] = char_list[r==char_list_len ? r-1 : r];
       }
       ret[num] = '\0';
       return ret;
   }
   
   //------------------
   int main(int argc, char *argv[])
   {
       char *rnd_out; //-- random data for browser output and file input
       char *rnd_file; //-- random file
       char *rnd_path; //-- for speed let's make on ramdisk /dev/shm/random-c/
       char *t;
       FILE *F;
   
       int num_char=10;
       int arg_cnt=1;
   
       if(argc>0){
           //-- why nobody love C ? one of the reason is these kind parsing thing
           while ((t = /*string.h->*/strtok(argv[0], "=")) != NULL) {
               argv[0] = NULL;
               if(arg_cnt == 2){
                   num_char = /*stdlib.h->*/atoi(t);
               }
               arg_cnt++;
           }
       }else{
           //-- get random number betwen 1 to 1000
           num_char = (rand() % 1000)+1;
       }
   
       init_random();
   
   
      //-- create random data
       rnd_out = get_rnd_char(num_char);
   
   
       //-- creating "log" path
       //-- why nobody love C ? more reason
      rnd_file = get_rnd_char(20);
      // "/dev/shm/random-c/xxxxxxxxxxxxxxxxxxxx" -> 38 chars + 1 for \0
      rnd_path = (char *)/*stdlib.h->*/malloc((38 * sizeof(char)) + 1);
      rnd_path[0] = '\0';
      /*string.h->*/strcat(rnd_path,"/dev/shm/random-c/");
      /*string.h->*/strcat(rnd_path,rnd_file);
   
       //-- save to file
       F = /*stdio.h->*/fopen(rnd_path,"w");
           /*stdio.h->*/fprintf(F,"%s",rnd_out);
       /*stdio.h->*/fclose(F);
   
   
      //-- send output to browser
      /*gwan.h->*/xbuf_cat(get_reply(argv), rnd_out);
   
   
       //-- cleanup memory
       //-- why nobody love C ? MAIN reason: no easy way of memory management
      /*stdlib.h->*/free(rnd_file);
      /*stdlib.h->*/free(rnd_out);
      /*stdlib.h->*/free(rnd_path);
   
      return 200; // return an HTTP code (200:'OK')
   }
   
   // ============================================================================
   // End of Source Code
   // ============================================================================
   

3. run on browser:

   http://localhost:8080/?random.c 
   

   then you should have one 20char random file at /dev/shm/random-c/

4. here the 'problem', run:

   ab -n 1000 'http://localhost:8080/?random.c'
   

   my ubuntu have output:

   Finished 1000 requests
   
   
   Server Software:        G-WAN
   Server Hostname:        localhost
   Server Port:            8080
   
   Document Path:          /?random.c
   Document Length:        440 bytes
   
   Concurrency Level:      1
   Time taken for tests:   0.368 seconds
   Complete requests:      1000
   Failed requests:        361
      (Connect: 0, Receive: 0, Length: 361, Exceptions: 0)
   Write errors:           0
   Total transferred:      556492 bytes
   HTML transferred:       286575 bytes
   Requests per second:    2718.73 [#/sec] (mean)
   Time per request:       0.368 [ms] (mean)
   Time per request:       0.368 [ms] (mean, across all concurrent requests)
   Transfer rate:          1477.49 [Kbytes/sec] received
   

   try:

   [bash]# ls /dev/shm/random-c/
   

   the directory only list 4 or 5 random files, which expected was 1000files

5. tested on random.c and perl's version random.pl

so the back to beginning question, how to disable GWAN internal cache, I try to read gwan user guide for set something in handler, but found nothing (or I miss something in that guide ).

thanks for GWAN team for this great product. any answer welcome .. thanks

Answer 1

我认为您正在谈论的功能是微缓存。要禁用它，URI 需要在 200 毫秒内对每个请求都是唯一的。（就像在 URI 上添加随机数）

G-WAN 常见问题解答状态：

“为了免除对前端缓存服务器的需求（并让 G-WAN 用作缓存反向代理），G-WAN 支持微缓存，这是一种 RESTful 功能。当以高并发调用给定 URI 时以及生成payload 需要很长时间，然后 G-WAN 会自动缓存一个页面 200 毫秒（Internet 上的平均延迟）以确保缓存是最新的：在 200 毫秒内，连续请求提供预期的结果。为防止触发微缓存，请对并发请求使用不断变化的查询参数（每个用户会话 id、随机数、计数器等）。

请注意，对于 v4.10+，默认情况下禁用缓存，请查看gwan/init.c文件。