Phew! We’ve covered a lot of ground in this book, and for most of our audience all of these ideas are new. With that in mind, we can’t hope to make you experts in these techniques. All we can really do is show you the broad-brush ideas, and just enough code for you to go ahead and write something from scratch.
The code we’ve shown in this book isn’t battle-hardened production code: it’s a set of Lego blocks that you can play with to make your first house, spaceship, and skyscraper.
That leaves us with two big tasks. We want to talk about how to start applying these ideas for real in an existing system, and we need to warn you about some of the things we had to skip. We’ve given you a whole new arsenal of ways to shoot yourself in the foot, so we should discuss some basic firearms safety.
How Do I Get There from Here?
Chances are that a lot of you are thinking something like this:
“OK Bob and Harry, that’s all well and good, and if I ever get hired to work on a green-field new service, I know what to do. But in the meantime, I’m here with my big ball of Django mud, and I don’t see any way to get to your nice, clean, perfect, untainted, simplistic model. Not from here.”
We hear you. Once you’ve already built a big ball of mud, it’s hard to know how to start improving things. Really, we need to tackle things step by step.
First things first: what problem are you trying to solve? Is the software too hard to change? Is the performance unacceptable? Have you got ...