【源码剖析】Webbench —— 简洁而优美的压力测试工具

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Webbench 是一个古老而著名的网站压力测试工具，简单而实用。如果你不清楚你的网站能承受多大的压力，或者你想分析对比两个网站的性能，webbench 再好用不过了。

Gitbub 地址：https://github.com/yangtingcheng/projectwithcomment/tree/master/webbench

安装：

很简单，cd 进项目主页后进行 make install clean 就好了。

用法：

想要知道用法可以在安装后直接输入 webbench 或 webbench -h 或 webbench --help. 可以看到：

    webbench [option]... URL        -f|--force               Don't wait for reply from server.        -r|--reload              Send reload request - Pragma: no-cache.        -t|--time <sec>          Run benchmark for <sec> seconds. Default 30.        -p|--proxy <server:port> Use proxy server for request.        -c|--clients <n>         Run <n> HTTP clients at once. Default one.        -9|--http09              Use HTTP/0.9 style requests.        -1|--http10              Use HTTP/1.0 protocol.        -2|--http11              Use HTTP/1.1 protocol.        --get                    Use GET request method.        --head                   Use HEAD request method.        --options                Use OPTIONS request method.        --trace                  Use TRACE request method.        -?|-h|--help             This information.        -V|--version             Display program version.

说一下主要的几个选项：指定 -f 时不等待服务器数据返回， -t 为指定压力测试运行时间， -c 指定由多少个客户端发起测试请求。

-9 -1 -2 分别为指定 HTTP/0.9 HTTP/1.0 HTTP/1.1。

示例：

访问 http://baidu.com/ , 一个客户端，持续 60 秒。

    ➜  webbench-1.5  webbench -t 60 http://www.baidu.com/      Webbench - Simple Web Benchmark 1.5      Copyright (c) Radim Kolar 1997-2004, GPL Open Source Software.            Benchmarking: GET http://www.baidu.com/      1 client, running 60 sec.            Speed=36 pages/min, 54150 bytes/sec.      Requests: 36 susceed, 0 failed.

（这校园网真是 ri le gou 了）

访问 http://baidu.com/ , 10 个客户端，持续 60 秒，socket 提前关闭。

➜ webbench-1.5 webbench -f -c 10 -t 60 http://www.baidu.com/
Webbench - Simple Web Benchmark 1.5
Copyright (c) Radim Kolar 1997-2004, GPL Open Source Software.
Benchmarking: GET http://www.baidu.com/
10 clients, running 60 sec, early socket close.
Speed=586 pages/min, 0 bytes/sec.
Requests: 586 susceed, 0 failed.

代码分析：

其实我把项目 clone 之后做的第一件事是把代码风格全部调整了....强迫症面对不一样的缩进和花括号都不能忍...

项目源码都位于 socket.c 和 webbench.c 两个 c 文件里面。其他都是说明文档或用于编译。

可能涉及知识点：命令行参数解析（getopt_long）信号处理（sigaction） socket 管道读写。这些都可以通过 man 相关函数或者直接百度，不赘述了。

主要函数：

alarm_handler 信号处理函数，时钟结束时进行调用。

usage 输出 webbench 命令用法

main 提供程序入口...

build_request 构造 HTTP 请求

bench 派生子进程，父子进程管道通信最后输出计算结果。

benchcore 每个子进程的实际发起请求函数。

主要流程：

说一下程序执行的主要流程：

1. 解析命令行参数，根据命令行指定参数设定变量，可以认为是初始化配置。

2.根据指定的配置构造 HTTP 请求报文格式。

3.开始执行 bench 函数，先进行一次 socket 连接建立与断开，测试是否可以正常访问。

4.建立管道，派生根据指定进程数派生子进程。

5.每个子进程调用 benchcore 函数，先通过 sigaction 安装信号，用 alarm 设置闹钟函数，接着不断建立 socket 进行通信，与服务器交互数据，直到收到信号结束访问测试。子进程将访问测试结果写进管道。

6.父进程读取管道数据，汇总子进程信息，收到所有子进程消息后，输出汇总信息，结束。

流程图：

注释源码：

socket.c:

    /* $Id: socket.c 1.1 1995/01/01 07:11:14 cthuang Exp $      *      * This module has been modified by Radim Kolar for OS/2 emx      */            /***********************************************************************       module:       socket.c       program:      popclient       SCCS ID:      @(#)socket.c    1.5  4/1/94       programmer:   Virginia Tech Computing Center       compiler:     DEC RISC C compiler (Ultrix 4.1)       environment:  DEC Ultrix 4.3        description:  UNIX sockets code.      ***********************************************************************/             #include <sys/types.h>      #include <sys/socket.h>      #include <fcntl.h>      #include <netinet/in.h>      #include <arpa/inet.h>      #include <netdb.h>      #include <sys/time.h>      #include <string.h>      #include <unistd.h>      #include <stdio.h>      #include <stdlib.h>      #include <stdarg.h>            int Socket(const char *host, int clientPort)      {          int sock;          unsigned long inaddr;          struct sockaddr_in ad;          struct hostent *hp;                /* 初始化地址 */          memset(&ad, 0, sizeof(ad));          ad.sin_family = AF_INET;                /* 尝试把主机名转化为数字 */          inaddr = inet_addr(host);          if (inaddr != INADDR_NONE)              memcpy(&ad.sin_addr, &inaddr, sizeof(inaddr));          else          {              /* 取得 ip 地址 */              hp = gethostbyname(host);              if (hp == NULL)                  return -1;              memcpy(&ad.sin_addr, hp->h_addr, hp->h_length);          }          ad.sin_port = htons(clientPort);                /* 建立 socket */          sock = socket(AF_INET, SOCK_STREAM, 0);          if (sock < 0)              return sock;          /* 建立链接 */          if (connect(sock, (struct sockaddr *)&ad, sizeof(ad)) < 0)              return -1;          return sock;      }

webbench.c:

/*  * (C) Radim Kolar 1997-2004  * This is free software, see GNU Public License version 2 for  * details.  *  * Simple forking WWW Server benchmark:  *  * Usage:  *   webbench --help  *  * Return codes:  *    0 - sucess  *    1 - benchmark failed (server is not on-line)  *    2 - bad param  *    3 - internal error, fork failed  *  */  #include "socket.c"  #include <unistd.h>  #include <sys/param.h>  #include <rpc/types.h>  #include <getopt.h>  #include <strings.h>  #include <time.h>  #include <signal.h>    /* values */  volatile int timerexpired = 0;  int speed = 0;  int failed = 0;  int bytes = 0;    /* globals */  int http10 = 1; /* 0 - http/0.9, 1 - http/1.0, 2 - http/1.1 */    /* Allow: GET, HEAD, OPTIONS, TRACE */  #define METHOD_GET 0  #define METHOD_HEAD 1  #define METHOD_OPTIONS 2  #define METHOD_TRACE 3  #define PROGRAM_VERSION "1.5"    /* 默认设置 */  int method = METHOD_GET; /* GET 方式 */  int clients = 1; /* 只模拟一个客户端 */  int force = 0; /* 等待响应 */  int force_reload = 0; /* 失败时重新请求 */  int proxyport = 80; /* 访问端口 */  char *proxyhost = NULL; /* 代理服务器 */  int benchtime = 30; /* 模拟请求时间 */    /* internal */  int mypipe[2]; /* 管道 */  char host[MAXHOSTNAMELEN]; /* 网络地址 */  #define REQUEST_SIZE 2048  char request[REQUEST_SIZE]; /* 请求 */    static const struct option long_options[]=  {      {"force",no_argument,&force,1},      {"reload",no_argument,&force_reload,1},      {"time",required_argument,NULL,'t'},      {"help",no_argument,NULL,'?'},      {"http09",no_argument,NULL,'9'},      {"http10",no_argument,NULL,'1'},      {"http11",no_argument,NULL,'2'},      {"get",no_argument,&method,METHOD_GET},      {"head",no_argument,&method,METHOD_HEAD},      {"options",no_argument,&method,METHOD_OPTIONS},      {"trace",no_argument,&method,METHOD_TRACE},      {"version",no_argument,NULL,'V'},      {"proxy",required_argument,NULL,'p'},      {"clients",required_argument,NULL,'c'},      {NULL,0,NULL,0}  };    /* prototypes */  static void benchcore(const char* host,const int port, const char *request);  static int bench(void);  static void build_request(const char *url);    static void alarm_handler(int signal)  {      timerexpired = 1;  }    /* help 信息 */  static void usage(void)  {     fprintf(stderr,      "webbench [option]... URL\n"      "  -f|--force               Don't wait for reply from server.\n"      "  -r|--reload              Send reload request - Pragma: no-cache.\n"      "  -t|--time <sec>          Run benchmark for <sec> seconds. Default 30.\n"      "  -p|--proxy <server:port> Use proxy server for request.\n"      "  -c|--clients <n>         Run <n> HTTP clients at once. Default one.\n"      "  -9|--http09              Use HTTP/0.9 style requests.\n"      "  -1|--http10              Use HTTP/1.0 protocol.\n"      "  -2|--http11              Use HTTP/1.1 protocol.\n"      "  --get                    Use GET request method.\n"      "  --head                   Use HEAD request method.\n"      "  --options                Use OPTIONS request method.\n"      "  --trace                  Use TRACE request method.\n"      "  -?|-h|--help             This information.\n"      "  -V|--version             Display program version.\n"      );  };    int main(int argc, char *argv[])  {      int opt = 0;      int options_index = 0;      char *tmp = NULL;        /* 不带参数时直接输出 help 信息 */      if(argc == 1)      {          usage();          return 2;      }        /* getopt_long 为命令行解析的库函数，可通过 man 3 getopt_long 查看 */      while((opt = getopt_long(argc,argv,"912Vfrt:p:c:?h",long_options,&options_index)) != EOF )      {          /* 如果有返回对应的命令行参数 */          switch(opt)          {              case  0 : break;              case 'f': force = 1;break;              case 'r': force_reload = 1;break;              case '9': http10 = 0;break;              case '1': http10 = 1;break;              case '2': http10 = 2;break;              case 'V':                        printf(PROGRAM_VERSION"\n");                        exit(0);              case 't':                        benchtime = atoi(optarg);                        break;              case 'p':                        /* proxy server parsing server:port */                        tmp = strrchr(optarg,':');                        proxyhost = optarg;                        if(tmp == NULL)                        {                            break;                        }                        if(tmp == optarg)                        {                            fprintf(stderr,"Error in option --proxy %s: Missing hostname.\n",optarg);                            return 2;                        }                        if(tmp == optarg + strlen(optarg)-1)                        {                            fprintf(stderr,"Error in option --proxy %s Port number is missing.\n",optarg);                            return 2;                        }                        *tmp = '\0';                        proxyport = atoi(tmp+1);                        break;              case ':':              case 'h':              case '?': usage();return 2;break;              case 'c': clients = atoi(optarg);break;          }      }        /* optind 被 getopt_long 设置为命令行参数中未读取的下一个元素下标值 */      if(optind == argc)      {          fprintf(stderr,"webbench: Missing URL!\n");          usage();          return 2;      }        /* 不能指定客户端数和请求时间为 0 */      if(clients == 0) clients = 1;      if(benchtime == 0) benchtime = 60;        /* Copyright */      fprintf(stderr,"Webbench - Simple Web Benchmark "PROGRAM_VERSION"\n"       "Copyright (c) Radim Kolar 1997-2004, GPL Open Source Software.\n"       );        /* 构造 HTTP 请求到 request 数组 */      build_request(argv[optind]);        /* 以下到函数结束为输出提示信息 */      /* print bench info */      printf("\nBenchmarking: ");      switch(method)      {          case METHOD_GET:          default:              printf("GET");break;          case METHOD_OPTIONS:              printf("OPTIONS");break;          case METHOD_HEAD:              printf("HEAD");break;          case METHOD_TRACE:              printf("TRACE");break;      }        printf(" %s",argv[optind]);      switch(http10)      {          case 0: printf(" (using HTTP/0.9)");break;          case 2: printf(" (using HTTP/1.1)");break;      }        printf("\n");        if(clients == 1) printf("1 client");      else          printf("%d clients",clients);        printf(", running %d sec", benchtime);      if(force) printf(", early socket close");      if(proxyhost != NULL) printf(", via proxy server %s:%d",proxyhost,proxyport);      if(force_reload) printf(", forcing reload");      printf(".\n");        /* 开始压力测试，返回 bench 函数执行结果 */      return bench();  }    void build_request(const char *url)  {      char tmp[10];      int i;        /* 初始化 */      bzero(host,MAXHOSTNAMELEN);      bzero(request,REQUEST_SIZE);        /* 判断应该使用的 HTTP 协议 */      if(force_reload && proxyhost != NULL && http10 < 1) http10 = 1;      if(method == METHOD_HEAD && http10 < 1) http10 = 1;      if(method == METHOD_OPTIONS && http10 < 2) http10 = 2;      if(method == METHOD_TRACE && http10 < 2) http10 = 2;        /*填写 method 方法 */      switch(method)      {          default:          case METHOD_GET: strcpy(request,"GET");break;          case METHOD_HEAD: strcpy(request,"HEAD");break;          case METHOD_OPTIONS: strcpy(request,"OPTIONS");break;          case METHOD_TRACE: strcpy(request,"TRACE");break;      }        strcat(request," ");        /* URL 合法性判断 */      if(NULL == strstr(url,"://"))      {          fprintf(stderr, "\n%s: is not a valid URL.\n",url);          exit(2);      }        if(strlen(url)>1500)      {          fprintf(stderr,"URL is too long.\n");          exit(2);      }        if(proxyhost == NULL)          if(0 != strncasecmp("http://",url,7))          {              /* 只支持 HTTP 地址 */              fprintf(stderr,"\nOnly HTTP protocol is directly supported, set --proxy for others.\n");              exit(2);          }        /* 找到主机名开始的地方 */      /* protocol/host delimiter */      i = strstr(url,"://")-url+3;        /* 必须以 / 结束*/      /* printf("%d\n",i); */      if(strchr(url+i,'/')==NULL)      {          fprintf(stderr,"\nInvalid URL syntax - hostname don't ends with '/'.\n");          exit(2);      }        if(proxyhost == NULL)      {          /* get port from hostname */          if(index(url+i,':') != NULL && index(url+i,':') < index(url+i,'/'))          {              strncpy(host,url+i,strchr(url+i,':')-url-i);              /* 端口 */              bzero(tmp,10);              strncpy(tmp,index(url+i,':')+1,strchr(url+i,'/')-index(url+i,':')-1);              /* printf("tmp=%s\n",tmp); */              /* 设置端口 */              proxyport = atoi(tmp);              if(proxyport==0) proxyport=80;            } else {              strncpy(host,url+i,strcspn(url+i,"/"));          }          // printf("Host=%s\n",host);            strcat(request+strlen(request),url+i+strcspn(url+i,"/"));      } else {          // printf("ProxyHost=%s\nProxyPort=%d\n",proxyhost,proxyport);          strcat(request,url);      }        if(http10 == 1)          strcat(request," HTTP/1.0");      else if (http10==2)          strcat(request," HTTP/1.1");      strcat(request,"\r\n");        if(http10 > 0)          strcat(request,"User-Agent: WebBench "PROGRAM_VERSION"\r\n");        if(proxyhost == NULL && http10 > 0)      {          strcat(request,"Host: ");          strcat(request,host);          strcat(request,"\r\n");      }        if(force_reload && proxyhost != NULL)      {          strcat(request,"Pragma: no-cache\r\n");      }        if(http10 > 1)          strcat(request,"Connection: close\r\n");        /* add empty line at end */      if(http10>0) strcat(request,"\r\n");      // printf("Req=%s\n",request);  }    /* vraci system rc error kod */  static int bench(void)  {      int i,j,k;      pid_t pid = 0;      FILE *f;        /* 作为测试地址是否合法 */      /* check avaibility of target server */      i = Socket(proxyhost == NULL?host:proxyhost, proxyport);      if(i < 0){          fprintf(stderr,"\nConnect to server failed. Aborting benchmark.\n");          return 1;      }      close(i);        /* 建立管道 */      /* create pipe */      if(pipe(mypipe))      {          perror("pipe failed.");          return 3;      }        /* not needed, since we have alarm() in childrens */      /* wait 4 next system clock tick */      /*      * cas=time(NULL);      * while(time(NULL)==cas)      * sched_yield();      * */        /* 派生子进程 */      /* fork childs */      for(i = 0;i < clients;i++)      {          pid = fork();          if(pid <= (pid_t)0)          {              /* child process or error*/              sleep(1); /* make childs faster */              break; /* 子进程立刻跳出循环，要不就子进程继续 fork 了 */          }      }        if( pid < (pid_t)0)      {          fprintf(stderr,"problems forking worker no. %d\n",i);          perror("fork failed.");          return 3;      }        if(pid == (pid_t)0)      {          /* 子进程发出实际请求 */          /* I am a child */          if(proxyhost == NULL)              benchcore(host,proxyport,request);          else              benchcore(proxyhost,proxyport,request);            /* 打开管道写 */          /* write results to pipe */          f = fdopen(mypipe[1],"w");          if(f == NULL)          {              perror("open pipe for writing failed.");              return 3;          }            /* fprintf(stderr,"Child - %d %d\n",speed,failed); */          fprintf(f,"%d %d %d\n",speed,failed,bytes);          fclose(f);            return 0;        } else {          /* 父进程打开管道读 */          f = fdopen(mypipe[0],"r");          if(f == NULL)          {              perror("open pipe for reading failed.");              return 3;          }            setvbuf(f,NULL,_IONBF,0);          speed = 0; /* 传输速度 */          failed = 0; /* 失败请求数 */          bytes = 0; /* 传输字节数 */            while(1)          {              pid = fscanf(f,"%d %d %d",&i,&j,&k);              if(pid<2)              {                  fprintf(stderr,"Some of our childrens died.\n");                  break;              }              speed += i;              failed += j;              bytes += k;              /* fprintf(stderr,"*Knock* %d %d read=%d\n",speed,failed,pid); */              /* 子进程是否读取完 */              if(--clients == 0) break;          }          fclose(f);            /* 结果计算 */          printf("\nSpeed=%d pages/min, %d bytes/sec.\nRequests: %d susceed, %d failed.\n",                  (int)((speed+failed)/(benchtime/60.0f)),                  (int)(bytes/(float)benchtime),                  speed,                  failed);      }      return i;  }    void benchcore(const char *host,const int port,const char *req)  {      int rlen;      char buf[1500];      int s,i;      struct sigaction sa;        /*安装信号 */      /* setup alarm signal handler */      sa.sa_handler = alarm_handler;      sa.sa_flags = 0;      if(sigaction(SIGALRM,&sa,NULL))          exit(3);        /* 设置闹钟函数 */      alarm(benchtime);        rlen = strlen(req);    nexttry:      while(1){          /* 收到信号则 timerexpired = 1 */          if(timerexpired)          {              if(failed > 0)              {                  /* fprintf(stderr,"Correcting failed by signal\n"); */                  failed--;              }              return;          }          /* 建立 socket, 进行 HTTP 请求 */          s = Socket(host,port);          if(s < 0)          {              failed++;              continue;          }          if(rlen!=write(s,req,rlen))          {              failed++;              close(s);              continue;          }          /* HTTP 0.9 的处理 */          if(http10==0)              /* 如果关闭不成功 */              if(shutdown(s,1))              {                  failed++;                  close(s);                  continue;              }            /* -f 选项时不读取服务器回复 */          if(force == 0)          {              /* read all available data from socket */              while(1)              {                  if(timerexpired) break;                  i = read(s,buf,1500);                  /* fprintf(stderr,"%d\n",i); */                  if(i<0)                  {                      failed++;                      close(s);                      goto nexttry;                  }                  else                      if(i == 0) break;                      else bytes+=i;              }          }          if(close(s))          {              failed++;              continue;          }          speed++;      }  }

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