webbench源码分析_webpack原理和机制

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Jetbrains全家桶1年46，售后保障稳定

webbench是一种网站的压力测试工具，它是由Lionbridge公司开发，wenbench的标准测试可以向我们展示两项内容：每秒钟相应的请求数和每秒钟传输的数据量；。webbench不但能具有便准静态页面的测试能力，还能对动态页面（ASP,PHP,Java,CGI）进 行测试的能力。还有就是他支持对含有SSL的安全网站例如电子商务网站进行静态或动态的性能测试。
Webbench最多可以模拟3万个并发连接去测试网站的负载能力。
webbench的源码很简单，只有socket.c和webbench.c两个文件，加起来也就500行左右的代码。

webbench的主要过程就是通过fork函数创建子进程，通过子进程去请求http，并将结果写入管道问件，父进程从管道文件中读出数据然后打印。

主要步骤：
main()函数：

• 调用usage()函数：打印输入提示信息
• getopt_long检查输入参数，并设置对应的选项，例如-t 30s,-c 1;
• build_request函数，该函数的功能是创建HTTP的请求报文request(全局变量)；请求行+首部行+空行
• 打印输出信息（方法、版本行、URL）
• 调用bench()函数，创建管道和子进程，对HTTP进行测试
  -调用benchcore()函数，进行HTTP测试
  
  • 调用socket.c文件中的Socket函数，进行tcp的请求连接

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;

    memset(&ad, 0, sizeof(ad));
    ad.sin_family = AF_INET;

    inaddr = inet_addr(host);
    if (inaddr != INADDR_NONE)
        memcpy(&ad.sin_addr, &inaddr, sizeof(inaddr));
    else
    {
        hp = gethostbyname(host);
        if (hp == NULL)
            return -1;
        memcpy(&ad.sin_addr, hp->h_addr, hp->h_length);
    }
    ad.sin_port = htons(clientPort);

    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0)
        return sock;
    if (connect(sock, (struct sockaddr *)&ad, sizeof(ad)) < 0)
        return -1;
    return sock;
}

Jetbrains全家桶1年46，售后保障稳定

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"
int method=METHOD_GET;//全局变量，指定http方法
int clients=1;//并发运行客户端的数量，默认是1
int force=0;//是否等待服务器响应，默认为不等待
int force_reload=0;
int proxyport=80;//代理服务器的端口号，默认80
char *proxyhost=NULL;//代理服务器的地址
int benchtime=30;//运行时间，默认为30s，可以通过-t修改
/* internal */
int mypipe[2];//为了创建管道
char host[MAXHOSTNAMELEN];
#define REQUEST_SIZE 2048
char request[REQUEST_SIZE];
//struct option结构体，配合getopt_long函数使用
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);//对http请求进行测试
static int bench(void);//调用子进程和管道，调用测试http函数
static void build_request(const char *url);//创建http请求
static void alarm_handler(int signal)
{
timerexpired=1;
}   
static void usage(void)//打印提示输入的帮助信息
{
fprintf(stderr,
"webbench [option]... URL\n"
" -f|--force Don't wait for reply from server.\n"//不等待服务器端的回应
" -r|--reload Send reload request - Pragma: no-cache.\n"//发送重新请求编译指示
" -t|--time <sec> Run benchmark for <sec> seconds. Default 30.\n"
" -p|--proxy <server:port> Use proxy server for request.\n"//使用代理服务请求
" -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[])//main函数
{
int opt=0;
int options_index=0;
char *tmp=NULL;
if(argc==1)//输入命令格式错误，打印提示消息
{
usage();
return 2;
} 
//检查输入参数，并设置对应的选项
while((opt=getopt_long(argc,argv,"912Vfrt:p:c:?h",long_options,&options_index))!=EOF )
{
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);//打印版本信息 PROGRAM_VERSION是宏
case 't': benchtime=atoi(optarg);break;  //修改运行时间，optarg表示命令后面的参数 webbench -t 30,30表示optarg 
case 'p': 
/* proxy server parsing server:port */
tmp=strrchr(optarg,':');//strrchr()查找字符在指定字符串中从后面开始第一次出现的位置
proxyhost=optarg;//设定地址
if(tmp==NULL)
{
break;//没有设定p选项
}
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;//并发运行的客户端
}
}
//optind为对应参数的下标位置
if(optind==argc) {
fprintf(stderr,"webbench: Missing URL!\n");
usage();
return 2;
}
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"
);
//使用中，最后为URL，对应为URL的位置，webbench -c 100 http://baidu.com:80/
build_request(argv[optind]);//创建http请求(实际行就是构建了http的请求报文request)
//打印一些输出的信息方法、HTTP版本号、并发运行客户端的数量、运行时间、
/* 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");
return bench();//创建管道和子进程，对HTTP请求进行测试
}
void build_request(const char *url)
{
char tmp[10];
int i;
bzero(host,MAXHOSTNAMELEN);//置字符串host前MAXHOSTNAMELEN字节为0，且包括'\0'
bzero(request,REQUEST_SIZE);
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;
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;
}
//请求行信息：方法+空格+URL+空格+HTTP版本+CRLF
strcat(request," ");
if(NULL==strstr(url,"://"))//strstr判断是否有子串
{
fprintf(stderr, "\n%s: is not a valid URL.\n",url);//若无"://",则为非法的URL
exit(2);
}
if(strlen(url)>1500)//URL太长，非法
{
fprintf(stderr,"URL is too long.\n");
exit(2);
}
//从url中获取代理服务器的地址
if(proxyhost==NULL)
if (0!=strncasecmp("http://",url,7)) 
{ fprintf(stderr,"\nOnly HTTP protocol is directly supported, set --proxy for others.\n");
exit(2);
}
/* protocol/host delimiter */
i=strstr(url,"://")-url+3;//获得IP地址起始位置距离URL的偏移量
/* printf("%d\n",i); */
if(strchr(url+i,'/')==NULL) {
//查找字符串中首次出现字符的位置
fprintf(stderr,"\nInvalid URL syntax - hostname don't ends with '/'.\n");
exit(2);
}
//获取代理服务器的端口号
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);//获取IP地址
bzero(tmp,10);
strncpy(tmp,index(url+i,':')+1,strchr(url+i,'/')-index(url+i,':')-1);//获取:与/之间的值，即端口号
/* printf("tmp=%s\n",tmp); */
proxyport=atoi(tmp);
if(proxyport==0) proxyport=80;
} else//不存在端口号的情况下
{
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);//若代理服务器的ip不为NULL，则不需要哦经过URL解析出IP地址，直接加上URL
}
if(http10==1)
strcat(request," HTTP/1.0");
else if (http10==2)
strcat(request," HTTP/1.1");
strcat(request,"\r\n");
//以上是HTTP请求报文的请求行信息request
//在空行之前以下是头部信息 (首部字段: 值\r\n)
if(http10>0)
strcat(request,"User-Agent: WebBench "PROGRAM_VERSION"\r\n");//版本行
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");
//空行信息
/* add empty line at end */
if(http10>0) strcat(request,"\r\n"); 
// printf("Req=%s\n",request);
}
//创建管道和子进程，对HTTP请求进行测试
/* vraci system rc error kod */
static int bench(void)
{
int i,j,k;    
pid_t pid=0;
FILE *f;
/* 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);
/* 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(); */
/* 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;
}
}
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，调用benchcore函数对http请求测试，获得speed、failded、bytes参数，写入管道文件
{
/* I am a child */
if(proxyhost==NULL)
benchcore(host,proxyport,request);//对HTTP请求进行测试
else
benchcore(proxyhost,proxyport,request);
/* write results to pipe */
f=fdopen(mypipe[1],"w");//fdopen取一个现存的文件描述符，并使一个标准的I/O流与该描述符结合，常用于由创建管道和网络通信通道函数获得描述符，因为这些特殊的文件不能用I/O标准I/O函数fopen函数打开。
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---从管道文件中读取数据输出
f=fdopen(mypipe[0],"r");
if(f==NULL) 
{
perror("open pipe for reading failed.");
return 3;
}
setvbuf(f,NULL,_IONBF,0);//_IONBF表示无缓存，直接从流中读入数据或直接向流中写入数据，而没有缓冲区
speed=0;
failed=0;
bytes=0;
while(1)//父进程读取管道数据，并做加法
{
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); */
if(--clients==0) break;
}
fclose(f);
//输出测试结果
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;
}
//对http进行测试，得到speed、Bytes 、failed
void benchcore(const char *host,const int port,const char *req)
{
int rlen;
char buf[1500];//存放服务器请求所返回的数据
int s,i;
struct sigaction sa;
/* setup alarm signal handler */
sa.sa_handler=alarm_handler;//设置定时器，信号处理函数
sa.sa_flags=0;
/* sigaction(),检查或修改与指定信号相关联的处理动作 */
//超时会产生SIGALRAM信号，调用alrm_handler函数处理信号
if(sigaction(SIGALRM,&sa,NULL))
exit(3);
alarm(benchtime);//开始设置闹钟，开始计时
/* alarm(),设置信号SIGALRM在经过seconds指定的秒数之后传递给当前的进程，如果seconds=0,表示取消闹钟，并将剩下的时间返回 */
rlen=strlen(req);
nexttry:while(1)//包含goto语句的while循环
{
if(timerexpired)
{
//计时结束，产生信号，信号处理函数将timerexpired置为 1，退出函数
if(failed>0)
{
/* fprintf(stderr,"Correcting failed by signal\n"); */
failed--;
}
return;
}
s=Socket(host,port); //调用socket.c文件中的Socket函数，建立TCP的连接 
if(s<0) { failed++;continue;} 
if(rlen!=write(s,req,rlen)) {failed++;close(s);continue;}//强向套接字文件中写入请求，和原请求长度不等，失败
if(http10==0) //针对HTTP/0.9班版本的特殊处理，HTTP0.9是端连接，一次只能进行一次HTTP请求
if(shutdown(s,1)) { failed++;close(s);continue;}
/* shutdown(int sockfd,int how):用于任何类型的套接口禁止接收、禁止发送或禁止收发数据 how : SHUT_RD(0):禁止读操作 SHUT_WR(1):禁止写操作 SHUT_RDWR(2):禁止读写 返回值：当没有错误发生，返回0，否则返回错误码 */
if(force==0) 
{
/* read all available data from socket */
while(1)
{
if(timerexpired) break; //超时，退出
i=read(s,buf,1500);//从socket中读取数据
/* fprintf(stderr,"%d\n",i); */
if(i<0) //读取数据失败
{ 
failed++;
close(s);
goto nexttry;//跳转下次循环
}
else//读取数据成功
if(i==0) break;
else
bytes+=i;
}
}
if(close(s)) {failed++;continue;}
speed++;//HTTP请求成功
}
}