This is a plugin for Traffic Server, that allows you to
configure mapping rules. 

To use this plugin, configure a remap.config rule like

   map http://foo.com http://bar.com @plugin=balancer.so @pparam=rotation:news


The "To-Url" in the remap.config rule is generally not used, unless the
lookup completely fails (i.e. this is a backup URL for extreme error
cases).


This is a list of all available options (set via @pparam):


    rotation  	  The name of the rotation (e.g. news) [to-host in remap]
    hash	  What to hash on, url, path, cookie, ip, header (primary)
    hash2	  Optional, secondary hash, to hash within a multi-host bucket
    bucketw	  Width of each hash bucket [1]


The rotation parameter specifies which rotation to do the lookup
on. If not specified, we will default to the same name as used in the To
URL in the remap rule.

The bucket width specifies how many hosts a particular hash bucket
should contain, for example:

    @pparam=bucketw:2

The hash parameter can be used zero or more times, without it, no hashing
is done at all. If you have more than one hash keys, they are concatenated
in the order specified. For example:

    @pparam=hash:ip @pparam=hash:cookie/B

The "header" hash key takes a required extra value, for example:

    @pparam=hash:header/Host


For "cookie" hash keys, you can optionally specify an identifier for which
cookie to use (without it, the entire cookie header is used). For example:

    @pparam=hash:cookie/B


The secondary hash ("hash2") is used to provide "stickiness" within a
bucket that's larger than one host (i.e. bucketw > 1). This allows you to
(for example) have a primary hash on the URL, where each URL is served by
some number of servers. A secondary hash on B-cookie would then provide
user stickiness, so that for a particular URL, a particular user will
always hit the same server.

If the hashes you've requested (either "hash" or "hash2") can not be
generated, we default to using the URL instead for the primary hash. For
the secondary hash, if set, we'll defaul to the src-IP. If these defaults
are not desirable, make sure that you have at least one hash key that is
guaranteed to exist (e.g. @pparam=hash:ip).

If no "hash" parameters are specified, no hashing is done. This is the
default behavior, obviously. In this cash, the "hash2" directive has no
effect as well.

Finally, a couple of "flag" options (parameters) are available, to control
some of the lookup mechanisms:

   - @pparam=hostip  will use the IP returned by the lookup


RELEASES
--------

Version 1.3.0 (8/23/10)
  - Fix off-by-one error when using IPs in the rewrite rules.
  - More efficient (and correct) management of various request resources.

Version 1.2.2 (6/15/09)
  - Fixed the build system.
  - Fixed the package info.

Version 1.2 (5/31/09)
  - Some code cleanup to make Coverity happy.
  - Added the @pparam=hostip to use the IP returned from the lookup
  instead of the host name.

Version 1.1 (5/8/09)
  - Changed all calls to use lookup() directly.
  - Fixed a bug with wrong size to MD5 calculations.

Version 1.0 (4/28/09)
  - Initial version, moderately tested...