In this chapter, we learned how to go from simple goroutines and instantiating channels to extending the basic functionality of goroutines and allowing cross-channel, bidirectional communication within concurrent processes. We looked at new ways to create blocking code to prevent our main process from ending before our goroutines. Finally, we learned about using select statements to develop reactive channels that are silent unless data is sent along a channel.

In our rudimentary web spider example, we employed these concepts together to create a safe, lightweight process that could extract all links from an array of URLs, grab the content via HTTP, and store the resulting response.

In the next chapter, we'll go beneath the surface to see how Go's internal scheduling manages concurrency and start using channels to really utilize the power, thrift, and speed of concurrency in Go.