Golang Goroutine Mutex with Example Read it later

In the world of concurrent programming, Golang has proved to be a popular programming language. It’s known for its built-in concurrency features like Goroutines, which are lightweight threads, and Channels, which allow communication between Goroutines. However, concurrent programming can be tricky, especially when there’s shared data, which could result in data races. That’s where Mutex comes in. In this blog, we’ll discuss Golang Goroutine Mutex and how to use it to prevent data races in Golang.

What is Goroutine Mutex in Golang?

Mutex stands for Mutual Exclusion. A Mutex is a synchronization primitive that allows only one Goroutine to access a shared resource at a time. When a Goroutine locks a Mutex, no other Goroutine can access the shared resource until the Mutex is unlocked. This ensures that concurrent access to the shared resource is safe, preventing data races.

The Golang Mutex is defined in the sync package. Here’s how to define a Mutex in Golang:

import "sync"

var mutex = &sync.Mutex{}

The above code defines a Mutex and initializes it. The sync.Mutex{} creates a new Mutex and returns a pointer to it. The var mutex = &sync.Mutex{} creates a variable named mutex that points to the Mutex.

How to use Mutex in Golang?

Using a Mutex in Golang is a three-step process:

1. Lock the Mutex
2. Access the shared resource
3. Unlock the Mutex

Let’s take a look at how to use a Mutex in Golang with an example:

package main

import (
    "fmt"
    "sync"
)

var (
    counter = 0
    mutex   = &sync.Mutex{}
)

func main() {
    var wg sync.WaitGroup
    for i := 0; i < 1000; i++ {
        wg.Add(1)
        go increment(&wg)
    }
    wg.Wait()
    fmt.Println("Counter:", counter)
}

func increment(wg *sync.WaitGroup) {
    mutex.Lock()
    defer mutex.Unlock()
    counter++
    wg.Done()
}

In the above code, we have a shared resource counter that is accessed by multiple Goroutines. We define a Mutex named mutex to protect access to the counter. The increment function is called by each Goroutine, which increments the counter by one. Before accessing the counter, the Goroutine acquires the Mutex using mutex.Lock(). After accessing the counter, the Goroutine releases the Mutex using mutex.Unlock(). The defer keyword is used to ensure that the Mutex is unlocked even if a panic occurs.

The sync.WaitGroup is used to wait for all Goroutines to finish before printing the final value of the counter.

Go Goroutine Mutex Advantages

1. Prevents data races: A Mutex prevents multiple Goroutines from accessing a shared resource simultaneously, ensuring that concurrent access is safe and preventing data races.
2. Synchronization: A Mutex can be used to synchronize access to a shared resource, ensuring that changes made by one Goroutine are visible to others.
3. Easy to use: The Golang Mutex is easy to use, with just three steps to follow – Lock, Access, Unlock.

Golang Goroutine Mutex Disadvantages

1. Deadlocks: Deadlocks can occur if a Goroutine acquires a Mutex and then waits indefinitely for another Mutex to be released. This can happen if multiple Mutexes are used and the order of acquiring and releasing them is not properly managed.
2. Performance overhead: Acquiring and releasing a Mutex involves some performance overhead, so excessive use of Mutexes can impact performance.

References

1. Go documentation: https://golang.org/pkg/sync/