Thursday, September 24, 2009

How To Turn Web Development Around (Part 2)

I did my best to outline the problem in Part 1. Now I have to stand up and propose some kind of solution. Otherwise, I'm just complaining and contributing nothing of real value.

Our frameworks make certain things easier. They don't provide tools to help us with other things. For some other set of activities, they may actually prohibit. The problem here is a combination. Django makes it easy to query your database and wrap functionality up into re-usable template tags. While I'm thankful for that, I am also realizing that ease of one thing can prohibit another. When one path is made easier it creates the perception of greater difficulty in other paths. I think this is why, when our web frameworks give us all these tools to response to a web request, we completely lack in everything we could do aside from that request.

How can we make it easier to work outside the web request?

We need some idea of what working outside the web request means. We also need to define these in terms that are useful when we do get around to that request handling we've already got.

Going back to the tag cloud example, we look at the resources created when we generate one. Aside the HTML snippet of the tag cloud itself, we build the data used in the cloud, consisting of all the unique tags and their counts. This is the kind of data that makes sense to store in your cache, but this fails the normal cache use case. We don't want to loose these generated resources when caches reset, so we need something less ephemeral. Any decent key-value store would be a good solution here.

Unfortunately basic Django signals are lacking. Another means of triggering the resource generation at the right times, with the right parameters, has to be found. It makes sense to actually use existing signals, which would add to a job queue.

The few remaining parts to give us easy mechanisms for inserting snippets into templates or grabbing generated datasets in views are all very simple. Together, the three layers come together to give us what our frameworks are leaving out today. Resources, to store non-cheap data. Jobs, to generate resources. Finally, Tools to acquire and use those resources. If I were an egotistical man, I might try to coin my own acronym and name this RJT.

I know this is nothing new. Rather than make the situation better, that actually makes it worse. As any project grows and matures, the cut corners need to be filled in. Everything here is eventually built, to different variations and with probably a lot more forethought (or a lot less, depending on the pressure.) The only difference is that large scale applications need to divert more resources to pushing, instead of pulling, whereas smaller scale applications simply should, because the benefits exists in either case. We won't all need to grow at exponential rates, but we should be doing better with whatever resources and whatever work load our application is given, small or large.

1 comment:

fumanchu said...

This is why CherryPy 3.1 built out its Engine to be a generic pub/sub mechanism: you can add arbitrary channels and run job queues etc outside the request process quite easily.

I write here about programming, how to program better, things I think are neat and are related to programming. I might write other things at my personal website.

I am happily employed by the excellent Caktus Group, located in beautiful and friendly Carrboro, NC, where I work with Python, Django, and Javascript.

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