我应该何时在golang中使用并发？

Question

So besides handling multiple server requests is there any other time that concurrency is relevant? I ask because it's so built into go that I feel wasteful if I don't use it but I can barely find a use for it.

Answer 1

Here is a good example from one of Go's inventors, Rob Pike, of using concurrency because it is an easier way to express the solution to a problem:

Lexical Scanning in Go

Generalizing on that a bit, any producer-consumer problem is a natural fit for 2 goroutines using a channel to pass outputs from the producer to the consumer.

Another good use for concurrency is interacting with multiple input/output sources (disks, network, terminal, etc.). Your program should be able to wake up and do some work whenever a result comes from any of these sources. It is possible to do this with one thread and a system call like poll(2) or select(2). When your thread wakes up, it must figure out which result came in, find where it left off in the relevant task, and pick up from there. That's a lot of code you need to write.

Writing that code is much easier using one goroutine per task. Then the state of that task is captured implicitly in the goroutine, and picking up where it left off is as simple as waking up and running.