Lesson 28. To err is human

After reading lesson 28, you’ll be able to

The sirens sound. Students and teachers shuffle out of classrooms to the nearest exit and congregate at the muster point. There’s no danger in sight and nothing is on fire. It’s another routine fire drill. Everyone is better prepared in the event of a real emergency.

File not found, invalid format, the server is unreachable. What does software do when something goes wrong? Maybe the problem can be extinguished, allowing operations to carry on as usual. Perhaps the best course of action is to exit safely, closing doors on the way out—or crash through a fourth story window as a last resort.

It’s important to have a plan. Consider the errors that could occur, how to communicate those errors, and the steps to handle them. Go keeps error handling front and center, encouraging you to think about failure and how to handle it. Like the tenth fire drill, error handling can feel mundane at times, but it ultimately leads to reliable software.

This lesson explores a few ways to handle errors and delves into how errors are made. It closes by contrasting Go’s style of error handling with that of other programming languages.

28.1. Handling errors

28.2. Elegant error handling

28.3. New errors

28.4. Don’t panic

Summary