[zeromq-dev] HWM behaviour & blocking

[Pieter Hintjens]

On Wed, May 9, 2012 at 7:45 AM, Steffen Mueller
<zeromq at steffen-mueller.net> wrote:

> Any chance I could have such a functionality? Of course, being able to
> determine whether there are any peers connected would be great, too.

The standard answer to "can I do funky routing model XYZ over 0MQ" is
"yes, you make it yourself using ROUTER sockets". This is why we
called them that. Particularly, the built-in HWM logic is difficult to
mix with routing and people who try this always end up frustrated.
Happily it is easy to layer on top.

It looks like you want a combination of reliable service-oriented
queue and credit-based flow control. Read the Guide section on
reliable request reply, in detail. Then read
http://unprotocols.org/blog:15. Mix this together, taste, improve,
repeat.

-Pieter