Go Goroutines

What are Goroutines?

Goroutines in Go are functions or methods that run concurrently with other functions or methods. They are the building blocks of concurrent programming in Go, allowing developers to efficiently manage multiple tasks at once without the overhead of traditional threads.

Unlike operating system threads, goroutines are managed by the Go runtime, which is highly efficient in terms of memory and speed. This allows thousands of goroutines to be executed on a single machine, making them a powerful tool for building scalable applications.

Creating a Simple Goroutine

Creating a goroutine is straightforward. By prefixing a function call with the go keyword, you can run that function concurrently with other goroutines. Here's a simple example:

In this example, the sayHello function is called as a goroutine. The time.Sleep function is used to ensure that the main function does not exit before the goroutine finishes executing. Without this delay, the program might end before the goroutine prints its message.

Goroutines and Anonymous Functions

Goroutines can also be used with anonymous functions, which are functions without a name. This can be useful for quickly defining and launching a goroutine:

The syntax go func() {...}() is used to create and execute an anonymous function as a goroutine. This is a common pattern in Go for quick and simple concurrent tasks.

Concurrency vs Parallelism

It is important to distinguish between concurrency and parallelism when working with goroutines. Concurrency is about dealing with lots of tasks at once, while parallelism is about doing lots of tasks at the same time. Goroutines enable concurrency; they allow multiple tasks to be handled at once. Whether these tasks run in parallel depends on the number of processors available.

Go's scheduler decides which goroutines run and when, making it possible for them to run on multiple threads when the hardware supports it.

Handling Goroutine Lifecycle

One of the challenges of using goroutines is managing their lifecycle. A goroutine's lifecycle is tied to the function that creates it. Once a function exits, any goroutines it spawned will also stop unless they are explicitly managed. Using channels (covered in the previous post) is a common method for managing communication and synchronization between goroutines.