如何大幅提升web前端性能之看tengine在大公司架构实践
在一个项目还是单体架构的时候，所有的js，css，image都会在一个web网站上，看起来并没有什么问题，比如下面这样：
但是当web网站流量起来的时候，这个单体架构必须要进行横向扩展，而在原来的架构中静态资源这羊毛是出在单体架构这头羊身上，所以横向多少
个单体，就有多少个静态资源文件夹，比如下面这样的架构。
那这种架构有什么问题呢？ 总的来说会有如下二个问题：
1. 浏览器对单一域名的请求有并发限制。
在同一个域名下，一般来说有js，css,img,media,html等等静态资源，如果资源都挂在同一个域名下，势必会影响页面的加载速度，而且单一域名
下静态资源还会带上同域名下的cookie等本不需要附加的信息。
2. 不方便管理和资源的浪费
为什么这么说呢？ 我们知道静态资源一般来说都是很占资源空间的，尤其是用户上传的头像，csv那更是占用web服务器资源，为了应对突发情况，
一般会保持web代码的3个版本的回滚策略，也就是说你需要在web1，web2，web3上同时进行3个静态资源文件夹的copy，相比单独用静态资源服务
器统一管理的文件夹的情况对比，前者的磁盘资源的浪费可想而知。。。所以改正后的架构应该是这样的。
有些同学可能会说，空口无凭，你得找点真实的案例给我看看，为了满足你的胃口，下面我就找下‘携程’ 和 ‘淘宝’站点给你分享一下。
一：携程首页对这二个问题的解决
啥也不想说，通过浏览器随便抓取一个css文件给大家分享一下，详细如下图：
1. css的加载路径
从http://webresource.c-ctrip.com/ResCRMOnline/R5/css/index/private_index.A_v3.css?ts=20170828_pro 中可以看到这和www.ctrip.com
域名根本就不是一个域名，除了有点像，不说话，甚至还有点想笑，所以这种方式的加载对页面的快速呈现有很大的帮助。
2. 对R5的分析
这个R5是什么意思，就是有10个版本，R1-R10，每发布一个新版本，R++，轮回而已，所以你可以将R5 -> R6，那就是轮回之前的css版本。
携程现在的静态资源大部分也是使用到了tengine,这是一个淘宝开源的基于nginx的proxy服务器，在nginx上面做了很多的优化，而且tengine很
大的一个亮点就是可以使用多文件合并加载，比如10个css文件，可以合并成一个css进行呈现，这就让10个http请求变成了1个，同样也是对页面
快速呈现有非常大的帮助，很可惜在ctrip上面并没有找到合并加载css,js的案例，或许还是历史的原因吧，那只能在taobao官网上找一下看看。
从上图中可以清楚看到tengine的强大功能，将default-min.css 和 apply-min.css 进行了合并加载，很神奇吧，接下来分享一下tengine的安装配置。
二：tengine安装
1. 下载地址：
可以去tengine官网（http://tengine.taobao.org/）上找到目前最新的 2.2.0的安装包。
[root@localhost myapp]# wget http://tengine.taobao.org/download/tengine-2.2.0.tar.gz --2017-09-02 19:54:07-- http://tengine.taobao.org/download/tengine-2.2.0.tar.gz Resolving tengine.taobao.org (tengine.taobao.org)... 120.55.149.135 Connecting to tengine.taobao.org (tengine.taobao.org)|120.55.149.135|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 2160648 (2.1M) [application/octet-stream] Saving to: ‘tengine-2.2.0.tar.gz’ 100%[===================================================================================================>] 2,160,648 2.11MB/s in 1.0s 2017-09-02 19:54:13 (2.11 MB/s) - ‘tengine-2.2.0.tar.gz’ saved [2160648/2160648] [root@localhost myapp]# tar -xzvf tengine-2.2.0.tar.gz [root@localhost myapp]# ls tengine-2.2.0 tengine-2.2.0.tar.gz [root@localhost myapp]# cd tengine-2.2.0 [root@localhost tengine-2.2.0]# ls AUTHORS.te CHANGES CHANGES.ru conf contrib html man packages README.markdown tests auto CHANGES.cn CHANGES.te configure docs LICENSE modules README src THANKS.te [root@localhost tengine-2.2.0]# pwd /root/myapp/tengine-2.2.0
2. 然后就是tengine的一些依赖包
[root@localhost myapp]# yum install -y zlib zlib-devel openssl openssl-devel pcre pcre-devel gcc gcc-c++
3. 常规的configure, make,make install
[root@localhost tengine-2.2.0]# ./configure --prefix=/usr/myapp/tengine checking for OS + Linux 3.10.0-327.el7.x86_64 x86_64 checking for C compiler ... found + using GNU C compiler + gcc version: 4.8.5 20150623 (Red Hat 4.8.5-11) (GCC) checking for gcc -pipe switch ... found checking for gcc builtin atomic operations ... found checking for C99 variadic macros ... found checking for gcc variadic macros ... found checking for compiler structure-packing pragma ... found checking for unistd.h ... found checking for inttypes.h ... found checking for limits.h ... found checking for sys/filio.h ... not found checking for sys/param.h ... found checking for sys/mount.h ... found checking for sys/statvfs.h ... found checking for crypt.h ... found checking for Linux specific features checking for epoll ... found checking for EPOLLRDHUP ... found checking for O_PATH ... found checking for sendfile() ... found checking for sendfile64() ... found checking for sys/prctl.h ... found checking for prctl(PR_SET_DUMPABLE) ... found checking for sched_setaffinity() ... found checking for crypt_r() ... found checking for SO_REUSEPORT ... found checking for sys/vfs.h ... found checking for nobody group ... found checking for poll() ... found checking for /dev/poll ... not found checking for kqueue ... not found checking for crypt() ... not found checking for crypt() in libcrypt ... found checking for F_READAHEAD ... not found checking for posix_fadvise() ... found checking for O_DIRECT ... found checking for F_NOCACHE ... not found checking for directio() ... not found checking for statfs() ... found checking for statvfs() ... found checking for dlopen() ... not found checking for dlopen() in libdl ... found checking for sysinfo() ... found checking for getloadavg() ... found checking for /proc/meminfo ... found checking for sched_yield() ... found checking for SO_SETFIB ... not found checking for SO_ACCEPTFILTER ... not found checking for TCP_DEFER_ACCEPT ... found checking for TCP_KEEPIDLE ... found checking for TCP_FASTOPEN ... found checking for TCP_INFO ... found checking for accept4() ... found checking for eventfd() ... found checking for int size ... 4 bytes checking for long size ... 8 bytes checking for long long size ... 8 bytes checking for void * size ... 8 bytes checking for uint64_t ... found checking for sig_atomic_t ... found checking for sig_atomic_t size ... 4 bytes checking for socklen_t ... found checking for in_addr_t ... found checking for in_port_t ... found checking for rlim_t ... found checking for uintptr_t ... uintptr_t found checking for system byte ordering ... little endian checking for size_t size ... 8 bytes checking for off_t size ... 8 bytes checking for time_t size ... 8 bytes checking for setproctitle() ... not found checking for pread() ... found checking for pwrite() ... found checking for sys_nerr ... found checking for localtime_r() ... found checking for posix_memalign() ... found checking for memalign() ... found checking for mmap(MAP_ANON|MAP_SHARED) ... found checking for mmap("/dev/zero", MAP_SHARED) ... found checking for System V shared memory ... found checking for POSIX semaphores ... not found checking for POSIX semaphores in libpthread ... found checking for struct msghdr.msg_control ... found checking for ioctl(FIONBIO) ... found checking for struct tm.tm_gmtoff ... found checking for struct dirent.d_namlen ... not found checking for struct dirent.d_type ... found checking for sysconf(_SC_NPROCESSORS_ONLN) ... found checking for openat(), fstatat() ... found checking for getaddrinfo() ... found checking for PCRE library ... found checking for PCRE JIT support ... found checking for OpenSSL library ... found checking for zlib library ... found creating objs/Makefile Configuration summary + using system PCRE library + using system OpenSSL library + md5: using OpenSSL library + sha1: using OpenSSL library + using system zlib library + jemalloc library is disabled nginx path prefix: "/usr/myapp/tengine" nginx binary file: "/usr/myapp/tengine/sbin/nginx" nginx configuration prefix: "/usr/myapp/tengine/conf" nginx configuration file: "/usr/myapp/tengine/conf/nginx.conf" nginx pid file: "/usr/myapp/tengine/logs/nginx.pid" nginx error log file: "/usr/myapp/tengine/logs/error.log" nginx http access log file: "/usr/myapp/tengine/logs/access.log" nginx http client request body temporary files: "client_body_temp" nginx dso module path: "/usr/myapp/tengine/modules/" nginx http proxy temporary files: "proxy_temp" nginx http fastcgi temporary files: "fastcgi_temp" nginx http uwsgi temporary files: "uwsgi_temp" nginx http scgi temporary files: "scgi_temp" [root@localhost tengine-2.2.0]# make && make install
4. 启动tengine下的nginx进程，可以看到当我启动之后，tengine的80端口已经打开了。
[root@localhost myapp]# ls tengine tengine-2.2.0 tengine-2.2.0.tar.gz [root@localhost myapp]# cd tengine [root@localhost tengine]# ls conf html include logs modules sbin [root@localhost tengine]# cd conf [root@localhost conf]# cd ../sbin [root@localhost sbin]# ls dso_tool nginx [root@localhost sbin]# ./nginx [root@localhost sbin]# netstat -tln Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN tcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN tcp6 0 0 :::22 :::* LISTEN tcp6 0 0 ::1:631 :::* LISTEN tcp6 0 0 ::1:25 :::* LISTEN [root@localhost sbin]#
三：css文件和合并加载的验证
1. css文件验证
下面在nginx.conf 中配置一下静态资源的访问路径，所有静态资源都是放在/usr目录下。
location ~ ^/(images|javascript|js|css|flash|media|static)/ { root /usr; }
然后生成 /usr/css/top.css 文件，最终浏览可以发现配置已生效。
[root@localhost usr]# mkdir css
[root@localhost usr]# ls
bin css etc games include lib lib64 libexec local myapp sbin share src tmp
[root@localhost usr]# cd css
[root@localhost css]# rz
[root@localhost css]# ls
top.css
2. css 合并压缩
这个合并模式还需要在tengine下安装一个ngx_http_concat_module 模块，可以看下官网：http://tengine.taobao.org/document_cn/http_concat_cn.html。
我这里采用静态编译，编译之前先把之前的tengine进程给关闭掉（nginx -s stop）。
[root@localhost myapp]# cd tengine-2.2.0 [root@localhost tengine-2.2.0]# ls AUTHORS.te CHANGES CHANGES.ru conf contrib html Makefile modules packages README.markdown tests auto CHANGES.cn CHANGES.te configure docs LICENSE man objs README src THANKS.te [root@localhost tengine-2.2.0]# ./configure --prefix=/usr/myapp/tengine --with-http_concat_module && make && make install
接下来只要在nginx.conf 中配置concat on，最多合并20个文件，最后 nginx -s reload 重启一下
location ~ ^/(images|javascript|js|css|flash|media|static)/ { root /usr; concat on; concat_max_files 20; concat_types text/css application/x-javascript; }
接下来再上传一个tips.css到/usr/css目录下，然后键入url：http://192.168.23.168/css/??top.css,tips.css ，，，终于大功告成啦。。。。
好了，本篇就说到这里，希望对你有帮助。。。
