Chapter 2. Core Storm concepts

The core concepts in Storm are simple once you understand them, but this understanding can be hard to come by. Encountering a description of “executors” and “tasks” on your first day can be hard to understand. There are just too many concepts you need to hold in your head at one time. In this book, we’ll introduce concepts in a progressive fashion and try to minimize the number of concepts you need to think about at one time. This approach will often mean that an explanation isn’t entirely “true,” but it’ll be accurate enough at that point in your journey. As you slowly pick up on different pieces of the puzzle, we’ll point out where our earlier definitions can be expanded on.

2.1. Problem definition: GitHub commit count dashboard

Let’s begin by doing work in a domain that should be familiar: source control in GitHub. Most developers are familiar with GitHub, having used it for a personal project, for work, or for interacting with other open source projects.

Let’s say we want to implement a dashboard that shows a running count of the most active developers against any repository. This count has some real-time requirements in that it must be updated immediately after any change is made to the repository. The dashboard being requested by GitHub may look something like figure 2.1.

2.2. Basic Storm concepts

2.3. Implementing a GitHub commit count dashboard in Storm

2.4. Summary