Issues with concurrency

Writing concurrent code in Go is elegant and simple. However, it does make our code more complex. Developers need to be familiar with the behavior of concurrency mechanisms to understand the code they are reading. Furthermore, as timing plays a crucial part in how goroutines behave, we might have a hard time reproducing potential bugs. In this section, we look at three common concurrency issues. As we deep dive into each example, we will also have the opportunity to understand the behavior of Go’s concurrency mechanisms.

Data races

A data race is the most common concurrency issue. This issue occurs when multiple goroutines access and modify the same shared resource concurrently. This is one of the reasons why we should avoid sharing the state between goroutines, preferring to share information between goroutines using channels.

We modify our previous greeting example by saving the formatted greetings into a slice, instead of immediately printing...