The Missing README

4 Writing Operable Code

Code does weird things when exposed to “the real world.” Users are unpredictable. Networks are unreliable. Things go wrong. Production software has to keep working. Writing operable code helps you deal with the unforeseen. Operable code has built-in protection, diagnostics, and controls. Protect your system by programming defensively with safe and resilient coding practices. Safe code prevents many failures, and resilient code recovers when failures do occur. You also need to be able to see what’s going on so you can diagnose failures. Expose logging, metrics, and call trace information for easy diagnostics. Finally, you need to control systems without rewriting code. An operable system has configuration parameters ...