I am not very familiar with messaging or message queues, so wanted to seek out some advice before spending time reinventing some well known wheel poorly.

I would like to have a broker that sits between an application and several endpoint services to which the application makes requests via the broker. These endpoint services have rules, typically throttling rules (i) you cannot submit more than x number of request per second (ii) you cannot queue up more than y number of requests at our end (iii) you must put a delay of z seconds after we have responded to a request of yours, etc., etc.

Is there a defacto standard open source software for this situation, that would take a config file describing the policies to follow for an end point. My requirement is pretty toy'ish, small to medium scale only. Just taking a look at Redis docs (am new to that too) it seems it will not be that hard to write out a simple solution. Would that be the way to go ? Or is there something out there that already handles this.