Worker Pools

What is a worker pool?

A worker pool is a set of threads that process jobs assigned to them. The Apache web server and the net/http package of Go more or less work this way: the main process accepts all incoming requests, which are forwarded to worker processes to get served. Once a worker process has finished its job, it is ready to serve a new client. Because Go does not have threads, the presented implementation is going to use goroutines instead of threads. Additionally, threads do not usually die after serving a request because the cost of ending a thread and creating a new one is too high, whereas goroutines do die after finishing their job. Worker pools in Go are implemented with the help of buffered channels because they allow us to limit the number of goroutines running at the same time.

Coding example

The presented utility implements a simple task: it processes integers and prints their square values using a single goroutine for serving each request. The code of wPools.go is as follows: