Dare has this to say about API versioning. His basic approach can be summarized as don’t change anything at all and separate your URL space using some version moniker. This is a good piece of advice but I’m more wary of other aspects of the posting such as the suggestion that we should support all versions over time to maintain backward compatibility.
I’m tempted to suggest that this is a classic Microsoft (and enterprise) mindset: pile up a stack of legacy and backward compatibility requirement which can potentially lead to a mess of complexity and brittleness underneath the APIs. I feel the reasoning around client migration also needs re-examination. This is because Live Messenger doesn’t live in a browser. It is a desktop native binary application and therefore has completely different characteristics from a genuine web application in terms of dispersal, upgrading and updates.
Consider that for many a browser based application, upgrades are but a reload away. Further many a web service that is mashed up as part of another offering will ultimately present to a user as a browser-based UI. i.e. We don’t need all our desktops to upgrade, we need to upgrade the integration point in the backend services of the mashups that use the web service. That’s at least potentially considerably fewer entities that need to upgrade than is normal in the desktop world.
Dare’s posting also seems to have an underlying current of belief that one can define an API perfectly in the first place. We have known for a long time that such a feat of prediction is often very difficult though it can be made more manageable via functional partitioning.
Limited lifetime is one of the best antidotes we have to the complexity of legacy and the brittleness of code. We resist it far too often leading to the mess we have in many an enterprise:
- Instability
- Slower Feature Delivery
- Difficult maintenance
The web, the human body and many real-world systems (cars for example) exploit the concept of limited lifetime successfully, perhaps this philosophy should be more widely applied in software?
Technorati Tags: architecture, browser, enterprise, evolution, versioning, web
Entries (RSS)