Part II Third-Party Frameworks and Libraries

Part I of this book delved deeply into what the Ruby standard library ships with, in terms of distributed programming, and how we can use that to build our distributed applications. Part II covers third-party frameworks and libraries that are available to either augment or replace DRb and Rinda.

Some of these tools offer a similar approach to what we are used to with DRb and Rinda, and others offer a radically different approach to distributed programming. We’ll talk about each package’s strengths and weaknesses, as well as when and where you might want to implement the library.

To give our discussions some context, we will first create our now-standard “Hello World” and “Distributed Logger” programs. In some cases the tool won’t quite lend itself to these examples, and that’s okay. That is all part of the evaluation process. We need to see how each tool handles the same task. From there we will learn if it’s appropriate for that task. Finally, we will move onto a project or two that showcases the uniqueness of the tool being discussed.

It’s important to note that just because a project makes it into our discussion in this part of the book doesn’t mean that it is the best tool, but rather that it has made some impact or represents a unique approach to the problem at hand. Other frameworks and libraries also didn’t make the cut. This doesn’t mean that those libraries are not valid or good. It just means that this book has limited space, and some decisions had to be made, or that those libraries were already duplicating important patterns and discussions that were already discussed.

Finally, please keep in mind that this part of the book is not meant to be a comprehensive manual for these libraries. You should use this part as a jumping-off point for your own discoveries. When you encounter a challenge in writing your distributed application, flip through the forthcoming chapters and see if one of the tools highlighted might help you. Then build the projects we discuss, look at the library’s source code, join a mailing list for it, Google it, or whatever other way you use to learn about something.