varnish purge

刚刚学习使用varnish，这个章节测试varnish的purge功能。

一、 配置vcl，在vcl中添加如下代码。可以参考官网配置，http://www.varnish-cache.org/trac/wiki/VCLExamplePurging

sub vcl_hit {
if (req.request == "PURGE") {
set obj.ttl = 0s;
error 200 "Purged.";
}
}

sub vcl_miss {
if (req.request == "PURGE") {
error 404 "Not in cache.";
}
}

二、 使用varnishadm来purge

1. 清除某个文件，$表示正则表达式的结尾附；

/opt/varnish/bin/varnishadm -T :4488 purge.url test.jpg$

2. 清除某个文件夹

varnishadm -T :4488 purge.url ^/images/.*$

三、通过varnishlog来验证，访问某个元素，每刷新一次，x-cache-hits会增加

[root@VMSHcentos01 ~]# /opt/varnish/bin/varnishlog -i TxHeader 13 TxHeader c Date: Fri, 13 May 2011 06:28:18 GMT 13 TxHeader c Via: 1.1 varnish 13 TxHeader c X-Varnish: 1688554888 13 TxHeader c Last-Modified: Thu, 14 Apr 2011 03:52:45 GMT 13 TxHeader c Cache-Control: max-age=31536000 13 TxHeader c Connection: keep-alive 13 TxHeader c X-Cache: HIT 13 TxHeader c X-Cache-Hits: 1 13 TxHeader c Date: Fri, 13 May 2011 06:28:26 GMT 13 TxHeader c Via: 1.1 varnish 13 TxHeader c X-Varnish: 1688554889 13 TxHeader c Last-Modified: Thu, 14 Apr 2011 03:52:45 GMT 13 TxHeader c Cache-Control: max-age=31536000 13 TxHeader c Connection: keep-alive 13 TxHeader c X-Cache: HIT 13 TxHeader c X-Cache-Hits: 2

执行purge，

/opt/varnish/bin/varnishadm -T :4488 purge.url 82839fc8-f49c-4191-bf02-420fe0c40310.jpg$

重新访问，看到Hits是0.

15 TxHeader b X-Varnish: 1688554890 13 TxHeader c Date: Fri, 13 May 2011 06:30:48 GMT 13 TxHeader c Via: 1.1 varnish 13 TxHeader c X-Varnish: 1688554890 13 TxHeader c Last-Modified: Thu, 14 Apr 2011 03:52:45 GMT 13 TxHeader c Cache-Control: max-age=31536000 13 TxHeader c Connection: keep-alive 13 TxHeader c X-Cache: MISS 13 TxHeader c X-Cache-Hits: 0