[背景]
Twitter 开源了他们自己用的一个 Apache 模块 mod_memcache_block（a distributed IP blocking system），这个模块根据 HTTP 代码请求限制访问频率。上周我装了下mod_memcache_block，出了很多错误，今天把它记录下来，供网上需要的朋友学习。
[过程]
下面的installation，是说明文档中的，不够详细，不过，放到前面供参考.
INSTALLATION
1. Install libmemcached-0.25 or better.
2. Install memcached-1.2.6
3. Edit the Makefile to indicate the location of libmemcached
4. Type "make", then "make install"
5. Update your apache configuration
6. Restart the server with apachectl restart
下载
wget http://download.tangent.org/libmemcached-0.25.tar.gz
wget http://memcached.googlecode.com/files/memcached-1.2.6.tar.gz
wget http://github.com/netik/mod_memcache_block/tarball/master
安装
(1)Apache已经安装，并且支持/加载了mod_so模块
查看
[root@study ~]# httpd -l
Compiled in modules:
core.c
prefork.c
http_core.c
mod_so.c
(2)安装libmemcached
./configure --prefix=/usr/local/libmemcached
make && make install
(3)安装memcached
./configure --prefix=/usr/local/memcached
make && make install
(4)安装mod_memcache_block
tar zxvf netik-mod_memcache_block-7b1fcec4d3ecdd7dbec9523a69338bbd1a6889be.tar.gz
cd netik-mod_memcache_block-7b1fcec4d3ecdd7dbec9523a69338bbd1a6889be
[root@study netik-mod_memcache_block-7b1fcec4d3ecdd7dbec9523a69338bbd1a6889be]# /usr/local/apache2/bin/apxs -I /usr/local/libmemcached/include/libmemcached -L /usr/local/libmemcached/lib -lmemcached -c -i -a mod_memcache_block.c
/usr/local/apache2/bin/httpd: error while loading shared libraries: libiconv.so.2: cannot open shared object file: No such file or directory
apxs:Error: Sorry, no shared object support for Apache.
apxs:Error: available under your platform. Make sure.
apxs:Error: the Apache module mod_so is compiled into.
apxs:Error: your server binary `/usr/local/apache2/bin/httpd'..
解决：vi /etc/ld.so.conf
/usr/local/lib
/usr/local/libmemcached/lib
ldconfig
[root@study netik-mod_memcache_block-7b1fcec4d3ecdd7dbec9523a69338bbd1a6889be]# /usr/local/apache2/bin/apxs -I /usr/local/libmemcached/include/libmemcached -L /usr/local/libmemcached/lib -lmemcached -c -i -a mod_memcache_block.c
/usr/local/apache2/build/libtool --silent --mode=compile gcc -prefer-pic -DLINUX=2 -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE -g -O2 -pthread -I/usr/local/apache2/include -I/usr/local/apache2/include -I/usr/local/apache2/include -I/usr/local/libmemcached/include/libmemcached -c -o mod_memcache_block.lo mod_memcache_block.c && touch mod_memcache_block.slo
In file included from mod_memcache_block.c:62:
/usr/local/libmemcached/include/libmemcached/memcached.h:21:46: error: libmemcached/memcached_constants.h: No such file or directory
/usr/local/libmemcached/include/libmemcached/memcached.h:22:42: error: libmemcached/memcached_types.h: No such file or directory
/usr/local/libmemcached/include/libmemcached/memcached.h:23:47: error: libmemcached/memcached_watchpoint.h: No such file or directory
/usr/local/libmemcached/include/libmemcached/memcached.h:24:40: error: libmemcached/memcached_get.h: No such file or directory
/usr/local/libmemcached/include/libmemcached/memcached.h:25:43: error: libmemcached/memcached_server.h: No such file or directory
/usr/local/libmemcached/include/libmemcached/memcached.h:26:43: error: libmemcached/memcached_string.h: No such file or directory
/usr/local/libmemcached/include/libmemcached/memcached.h:27:43: error: libmemcached/memcached_result.h: No such file or directory
In file included from mod_memcache_block.c:62:
/usr/local/libmemcached/include/libmemcached/memcached.h:73: error: expected specifier-qualifier-list before 鈥榤emcached_allocated鈥?
解决:vi /usr/local/libmemcached/include/libmemcached/memcached.h
修改
#include <libmemcached/libmemcached_config.h>
#endif
#include <libmemcached/memcached_constants.h>
#include <libmemcached/memcached_types.h>
#include <libmemcached/memcached_watchpoint.h>
#include <libmemcached/memcached_get.h>
#include <libmemcached/memcached_server.h>
#include <libmemcached/memcached_string.h>
#include <libmemcached/memcached_result.h>
为：
#include <libmemcached_config.h>
#endif
#include <memcached_constants.h>
#include <memcached_types.h>
#include <memcached_watchpoint.h>
#include </memcached_get.h>
#include </memcached_server.h>
#include </memcached_string.h>
#include </memcached_result.h>
再次执行
[root@study netik-mod_memcache_block-7b1fcec4d3ecdd7dbec9523a69338bbd1a6889be]# /usr/local/apache2/bin/apxs -I /usr/local/libmemcached/include/libmemcached -L /usr/local/libmemcached/lib -lmemcached -c -i -a mod_memcache_block.c
/usr/local/apache2/build/libtool --silent --mode=compile gcc -prefer-pic -DLINUX=2 -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE -g -O2 -pthread -I/usr/local/apache2/include -I/usr/local/apache2/include -I/usr/local/apache2/include -I/usr/local/libmemcached/include/libmemcached -c -o mod_memcache_block.lo mod_memcache_block.c && touch mod_memcache_block.slo
/usr/local/apache2/build/libtool --silent --mode=link gcc -o mod_memcache_block.la -L/usr/local/libmemcached/lib -lmemcached -rpath /usr/local/apache2/modules -module -avoid-version mod_memcache_block.lo
/usr/local/apache2/build/instdso.sh SH_LIBTOOL='/usr/local/apache2/build/libtool' mod_memcache_block.la /usr/local/apache2/modules
/usr/local/apache2/build/libtool --mode=install cp mod_memcache_block.la /usr/local/apache2/modules/
cp .libs/mod_memcache_block.so /usr/local/apache2/modules/mod_memcache_block.so
cp .libs/mod_memcache_block.lai /usr/local/apache2/modules/mod_memcache_block.la
cp .libs/mod_memcache_block.a /usr/local/apache2/modules/mod_memcache_block.a
chmod 644 /usr/local/apache2/modules/mod_memcache_block.a
ranlib /usr/local/apache2/modules/mod_memcache_block.a
PATH="$PATH:/sbin" ldconfig -n /usr/local/apache2/modules
----------------------------------------------------------------------
Libraries have been installed in:
/usr/local/apache2/modules
If you ever happen to want to link against installed libraries
in a given directory, LIBDIR, you must either use libtool, and
specify the full pathname of the library, or use the `-LLIBDIR'
flag during linking and do at least one of the following:
- add LIBDIR to the `LD_LIBRARY_PATH' environment variable
during execution
- add LIBDIR to the `LD_RUN_PATH' environment variable
during linking
- use the `-Wl,--rpath -Wl,LIBDIR' linker flag
- have your system administrator add LIBDIR to `/etc/ld.so.conf'
See any operating system documentation about shared libraries for
more information, such as the ld(1) and ld.so(8) manual pages.
----------------------------------------------------------------------
chmod 755 /usr/local/apache2/modules/mod_memcache_block.so
[activating module `memcache_block' in /usr/local/apache2/conf/httpd.conf]
OK,已经安装，并且加载到httpd.conf里了。让我们检查下
[root@study netik-mod_memcache_block-7b1fcec4d3ecdd7dbec9523a69338bbd1a6889be]# more /usr/local/apache2/conf/httpd.conf|grep mod_memcache_block
LoadModule memcache_block_module modules/mod_memcache_block.so
OK，重启下apache,下面让我们来玩玩配置吧!~
(5)配置，测试
/usr/local/memcached/bin/memcached -d -m 64 -l 192.168.1.4 -p 11211 -u www
在httpd.conf的主配置区域添加
<IfModule memcache_block_module>
MBEnable On
MBTimeout 2
MBServers 192.168.1.4:11211
MBPrefix block
MBExpiration 3600
MBMaxBlocks 10
MBResponseLimit 304 50 3600 <=304是我测试用的，大家根据自己的生产环境自己选择CODE
</IfModule>
参
测试结果
(1)当我在1个小时内，出现304 50次下，访问正常
(2) 当我在1个小时内，出现304 50次上，访问受到拒绝
注：
我对MBResponseLimit理解:
在指定时间（3600）秒，一个固定的IP访问的CODE（304）出现的次数低于Count(50)，那么就正常，否则，将其IP记录到memcached中(过期时间为：MBExpiration)，并加以拒绝访问。
再看memcached
STAT cmd_get 55
STAT cmd_set 5
memcached读取与设置已经开始工作了，如果再配置上对memcached的监控，那看得更清楚了。
参考：http://github.com/netik/mod_memcache_block/tarball/master
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来源：oschina
链接：https://my.oschina.net/u/4305447/blog/4339668