Chapter 11: Logging and Debugging

Overview

In every application you build, robust logging and debugging mechanisms can save you hours of effort trying to track down problems that might occur.

Logs can be used to help you analyze historical usage patterns that can't be obtained through the Web server log, such as server load, specific SQL statements that were executed, or application-specific messages that wouldn't otherwise be captured.

A debugging mechanism allows you to examine the values of variables, see which conditional loops are being executed, or otherwise determine the state of the application at runtime without having to litter your code with print statements that will need to be deleted before you deploy. After you've worked through the code in this chapter, you'll have a set of classes that should be a part of every project you work on.