缓存：高命中率的varnish缓存配置分享

backend slogra {
.host = "172.0.0.1";
.port = "80";
.connect_timeout = 20s;
.first_byte_timeout = 20s;
.between_bytes_timeout = 20s;
}

#允许刷新缓存的规则
acl purgeAllow {
# 只能本机进行刷新
"localhost";
}

# Below is a commented-out copy of the default VCL logic. If you
# redefine any of these subroutines, the built-in logic will be
# appended to your code.

sub vcl_recv {
#判断请求主机,跳转到相应后端主机
if(req.http.host ~ "^(.*)(slogra.com)")
{
set req.backend=slogra;
}else{
error 408 "Hostname not found";
}

#grace缓存过期仍存放
# 若backend是健康的，则仅grace 5s，如果backend不健康，则grace 1m。
# 这里，5s的目的是为了提高高并发时的吞吐率；
# 1m的目的是，backend挂了之后，还能继续服务一段时间，期望backend挂的不要太久。。。
if (req.backend.healthy) {
set req.grace = 5s;
} else {
set req.grace = 1m;
}

#刷新缓存的处理
if (req.request == "PURGE"){
if(!client.ip ~ purgeAllow) {
error 405 "Not allowed.";
}
# #转到hit或者miss处理
return (lookup);
}

#移除一些特定格式的cookie
if (req.url ~ "^(.*)\.(jpg|png|gif|jpeg|flv|bmp|gz|tgz|bz2|tbz|js|css|html|htm)($|\?)" ) {
#移除cookie,以便能缓存到varnish
unset req.http.cookie;
}

#Accept-Encoding 是浏览器发给主机,声明浏览器支持的编码类型的
#修正客户端的Accept-Encoding头信息
#防止个别浏览器发送类似 deflate, gzip
if (req.http.Accept-Encoding) {
if (req.url ~ "^(.*)\.(jpg|png|gif|jpeg|flv|bmp|gz|tgz|bz2|tbz)($|\?)" ) {
remove req.http.Accept-Encoding;
}else if (req.http.Accept-Encoding ~ "gzip"){
set req.http.Accept-Encoding = "gzip";
} else if (req.http.Accept-Encoding ~ "deflate"){
set req.http.Accept-Encoding = "deflate";
} else if (req.http.Accept-Encoding ~ "sdch"){
#chrome新增加的压缩
set req.http.Accept-Encoding = "sdch";
}else {
remove req.http.Accept-Encoding;
}
}
#首次访问增加X-Forwarded-For头信息,方便后端程序获取客户端ip
if (req.restarts == 0) {
if (req.http.x-forwarded-for) {
set req.http.X-Forwarded-For =
req.http.X-Forwarded-For + ", " + client.ip;
} else {
set req.http.X-Forwarded-For = client.ip;
}
}

if (req.request != "GET" &&
req.request != "HEAD" &&
req.request != "PUT" &&
req.request != "POST" &&
req.request != "TRACE" &&
req.request != "OPTIONS" &&
req.request != "DELETE") {
return (pipe);
}
if (req.request != "GET" && req.request != "HEAD") {
/* We only deal with GET and HEAD by default */
return (pass);
}
if (req.http.Authorization) {
/* Not cacheable by default */
return (pass);
}
#js,css文件都有Cookie,不能每次都去后台主机去取
#if (req.http.Cookie) {
# /* Not cacheable by default */
# return (pass);
#}

#如果请求的是动态页面直接转发到后端主机
if (req.url ~ "^(.*)\.(php|jsp|do|aspx|asmx|ashx)($|.*)") {
return (pass);
}
return (lookup);
}
sub vcl_pipe {
# Note that only the first request to the backend will have
# X-Forwarded-For set. If you use X-Forwarded-For and want to
# have it set for all requests, make sure to have:
# set bereq.http.connection = "close";
# here. It is not set by default as it might break some broken web
# applications, like IIS with NTLM authentication.
return (pipe);
}
#放过,让其直接去后台主机请求数据
sub vcl_pass {
return (pass);
}
sub vcl_hash {
hash_data(req.url);
if (req.http.host) {
hash_data(req.http.host);
} else {
hash_data(server.ip);
}
#支持压缩的要增加,防止发送给不支持压缩的浏览器压缩的内容
if(req.http.Accept-Encoding){
hash_data(req.http.Accept-Encoding);
}
return (hash);
}

#缓存主机lookup查找命中:hit
sub vcl_hit {
#刷新缓存的请求操作,设置TTL为0,返回处理结果代码
if (req.request == "PURGE") {
set obj.ttl = 0s;
error 200 "Purged.";
}
#缓存主机命中后(查找到了)
return (deliver);
}
#缓存主机lookup查找没有命中:miss
sub vcl_miss {
#刷新缓存的请求操作,
#if (req.request == "PURGE") {
# error 404 "Not in cache.";
#}
#缓存主机没有命中(去后台主机取)
return (fetch);
}
#从后台主机取回数据后,视情况是否进行缓存
sub vcl_fetch {
#如果请求的是动态页面直接发转发
#动态请求回来的,一定要放在前面处理
if (req.url ~ "^(.*)\.(php|jsp|do|aspx|asmx|ashx)($|.*)") {
set beresp.http.Cache-Control="no-cache, no-store";
unset beresp.http.Expires;
return (deliver);
}
# 仅当该请求可以缓存时，才设置beresp.grace，若该请求不能被缓存，则不设置beresp.grace
if (beresp.ttl > 0s) {
set beresp.grace = 1m;
}
if (beresp.ttl <= 0s ||
beresp.http.Set-Cookie ||
beresp.http.Vary == "*") {
/*
* Mark as "Hit-For-Pass" for the next 2 minutes
*/
set beresp.ttl = 120 s;
#下次请求时不进行lookup,直接pass
return (hit_for_pass);
}
#设置从后台主机获得的特定格式文件的缓存TTL
if (req.url ~ "^(.*)\.(pdf|xls|ppt|doc|docx|xlsx|pptx|chm|rar|zip)($|\?)")
{
#移除主机发送的cookie
unset beresp.http.Set-Cookie;
#加上缓存时间
set beresp.ttl = 30d;
return (deliver);
}else if(req.url ~ "^(.*)\.(bmp|jpeg|jpg|png|gif|svg|png|ico|txt|css|js|html|htm)($|\?)"){
#移除主机发送的cookie
unset beresp.http.Set-Cookie;
#加上缓存时间
set beresp.ttl = 15d;
return (deliver);
}else if(req.url ~ "^(.*)\.(mp3|wma|mp4|rmvb|ogg|mov|avi|wmv|mpeg|mpg|dat|3pg|swf|flv|asf)($|\?)"){
#移除主机发送的cookie
unset beresp.http.Set-Cookie;
#加上缓存时间
set beresp.ttl = 30d;
return (deliver);
}
#从后台主机返回的response信息中,没有缓存的,不缓存
if (beresp.http.Pragma ~"no-cache" || beresp.http.Cache-Control ~"no-cache" || beresp.http.Cache-Control ~"private") {
return (deliver);
}
return (deliver);
}
#缓存主机发送到客户端前调用
sub vcl_deliver {
#下面是添加一个Header标识，以判断缓存是否命中。
if (obj.hits > 0) {
set resp.http.X-Cache = "HIT from cache";
#set resp.http.X-Varnish = "HIT from cache";
} else {
set resp.http.X-Cache = "MISS from cache";
#set resp.http.X-Varnish = "MISS from cache";
}
#去掉不是必须的header
unset resp.http.Vary;
unset resp.http.X-Powered-By;
unset resp.http.X-AspNet-Version;
return (deliver);
}

sub vcl_error {
set obj.http.Content-Type = "text/html; charset=utf-8";
set obj.http.Retry-After = "5";
synthetic {"
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<title>"} + obj.status + " " + obj.response + {"</title>
</head>
<body>
<h1>Error "} + obj.status + " " + obj.response + {"</h1>
<p>"} + obj.response + {"</p>
<h3>Guru Meditation:</h3>
<p>XID: "} + req.xid + {"</p>
<hr>
<p>cache server</p>
</body>
</html>
"};
return (deliver);
}
sub vcl_init {
return (ok);
}
sub vcl_fini {
return (ok);
}