ext_delayer_acl8

Usage

Overview

Squid external acl helper; causes squid to delay responding to HTTP requests.

By carefully crafting the ACLs of a Squid setup it is possible to selectively delay requests received by a proxy. After the configured amount of time, it will always return "true".

Options

--help or -h

Print help message to stdout

--debug or -d

Emit debugging output to STDERR and ultimately cache.log

--log /path/to/file or -l /path/to/file

Emit debugging output to specified file instead of STDERR. Also turns on debugging

--wait msec or -w msec

Delay each request by the specified amount of msec. Unless this option is specified, by default each submitted request will be delayed by half a second (500 msec).

Configuration

To engage it, this snippet of configuration template can be used in squid.conf:

 external_acl_type delayer concurrency=100000 children-max=2 children-startup=1 children-idle=1 cache=10 %URI /path/to/delayer -w 200
 acl delay external delayer
 http_access allow acl1 acl2 acl3 delay !all

It is important that the acl referencing the delayer be the penultimate clause in the http_access line. It will cause delay to all requests that match all the preceding acls in the line. The !all clause at the end of the line will make it so that no traffic is authorized by this ACL, only the delay to evaluate the delay clause will be inserted before evaluating following http_access lines. It is also important to place the http_access line carefully in the sequence of all http_access_lines; it should be near the beginning, but be careful not to insert unwanted slow acls (especially proxy_auth).

It is possible to customize how delay is calculated for each request by modifying the "calc_delay" PERL function in the script, documentation on this is embedded in the source code comments.

Questions

Questions on the usage of this program can be sent to the Squid Users mailing list <[email protected]>