Pragmatic Dictator

Say the word messaging to a subset of developers and for some reason the immediate knee-jerk is to assume that means using some kind of message broker (Tibco, ActiveMQ or whatever). Utter the term “asynchronous communication” and that is typically equated to messaging and thus also implies use of a message broker.

I find this strange because messaging is possible via a myriad of methods including carrier pigeon, pony express, tcp, multicast, http and many other transports. As for supporting asynchronous operations well that’s governed by the API(s) provided by the transport. In fact this is only partially true because a lower-level synchronous API can be wrapped in an additional layer to produce an asynchronous API. Transports and layering are often seen together, for example it allows us to introduce support for reliable delivery if the underlying transport is not robust (often it isn’t).

There’s no denying that all (or most) of these features (asynchronous APIs, messaging, reliable delivery) are provided in various of the message broker implementations but rarely in the form of a set of composable layers. The preferred approach is usually a myriad of configuration options leaving us at the mercy of the vendor to provide and support just the right combination of configuration possibilities to match our design challenge.

The indivisible nature of these brokers hampers us in other ways too. It can be difficult to use the broker purely for messaging without being forced to work with say its models for routing control and security. I’m sure this is appealing to the vendors but it doesn’t seem like such a great deal to me.

Technorati Tags: architecture, design, messaging

This entry was posted on Tuesday, February 5th, 2008 at 11:09 pm and is filed under Architecture. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.