When developing for macOS, iOS, tvOS, or watchOS to get the best performance or provide a secure solution you often need to develop apps that run asynchronously using tools such as XPC, GCD, and NSOperationQueue. Debugging this type of code can be difficult, especially when data is being passed between queues, threads, or processes.
Logging is an age old technique to help in these situations, but it’s easy to be overwhelmed by the amount of log data and to introduce or mask problems because of the observer effect — the overhead associated with many logging frameworks. I know logging isn’t exactly going to steal the headlines away from Siri integration or watchOS 3, but as a developer it’s a valuable debugging tool and the changes in these APIs look to save some significant time while debugging crashes and squashing bugs.
The intent of this article is to approach development and debugging of Ruby on Rails applications from the perspetive of a C++ developer. In Part I I discussed some of the fundamental differences between Ruby on Rails and C++ development.
I started a simple "blog with comments" example to step through and showed how to use the ruby console to debug the model and what some of the exception messages returned to the view are telling us.
Where are the exceptions?
While we know the model is right (we debugged it already) sometimes there is no exception information being displayed. Where do we turn then? In this part of the article I am going to expand on our example and go deeper into what to look for there are no meaningful exception messages.
If you already know why C++ and Ruby on Rails are fundamentally different and just want to see the example, you can skip to The Example.
I’ve been developing software for many years but, for the most part, have stayed in the C++ world. I made the transition to web applications development with C# ASP.NET MVC applications, which I felt is a fairly easy transition. Adjusting to the MVC design pattern took a little change in thinking but it’s not a terribly difficult pattern to understand. It’s been a few years now and I am quite comfortable in that world.