How to randomize proxy selection

[Dmitry Kurochkin]

Hi Erico.

> Dears,
>
> I'm implementing a mesh proxy cluster and trying to randomize proxy IP
> address of cluster nodes, for peformance evaluation purposes.
>
> I'm executing PG Server as:
> sudo polygraph-server --config zipf.pg -verb_lvl 10
>
> and PG client as:
> polygraph-client --proxy 192.168.15.254:3128 --config zipf.pg --verb_lvl 10
>
> by I wish to do the following:
> polygraph-client --proxy 192.168.15.*251-254*:3128 --config zipf.pg--verb_lvl 10
>
> however traditional PG address range sintax 192.168.15.251-254:3128 doesn't
> work for --proxy.
>
> The goal is fill the memory of cluster nodes in a balanced way.
> Is there any additional alternative sintax that can I try?
>

It is not possible to give multiple proxy addresses to the Polygraph
client on command line.  You should specify it in the workload instead.
PGL Robot type has two fields for configuring proxies: http_proxies and
ftp_proxies.  These fields are available since Polygraph v4.0.4. Earlier
versions use the deprecated proxies field.  For HTTP your workload may
look like:

  ...
  Robot R = {
    ...
    addresses = [ '192.168.15.1' ** 10 ]; // use clone operator to create 10 robots
    http_proxies = [ '192.168.15.251-254:3128' ];
  };
  ...

Note that proxy selection is sticky.  I.e. a Robot selects a random
proxy at the configuration time and uses that single proxy for the
entire duration of the test.  This matches a typical client behavior
when a browser has a configured proxy that does not change.  So you need
multiple Robots to use more than one proxy server.

More information on proxy configuration is available at [1].

Regards,
  Dmitry

[1] http://www.web-polygraph.org/docs/reference/pgl/types.html#type:docs/reference/pgl/types/Robot

> I hope I'm clear enough.
>
> Thanks in advance,
>
> Erico.