Go Routines

Definition of a goroutine

• A goroutine is a lightweight thread of execution.
• A goroutine is a function that is capable of running concurrently with other functions.
• Goroutines are multiplexed onto multiple OS threads so if one should block, such as while waiting for I/O, others continue to run.
• Goroutine design hides many of the complexities of thread creation and management.

Goroutines Effective Go

Usage of a goroutine

To create a goroutine we use the keyword go followed by a function invocation

package workshop

import (
    "fmt"
    "sync"
)

func blockingPrint(messages []string) {
    for i := 0; i < len(messages); i++ {
        fmt.Println(messages[i])
    }
}

func goRoutines() {
    var wg sync.WaitGroup
    wg.Add(2)

    messages := []string{
        "My", "Next", "message",
    }
    blockingPrint(messages)

    go func(msg string) {
        defer wg.Done()
        fmt.Println(msg)
    }("Block Print")

    go func(msg string) {
        defer wg.Done()
        fmt.Println(msg)
    }("Block Print number 2")

    wg.Wait()
}

// Output here
// My
// Next
// message
// Block Print number 2
// Block Print

1. Notice here that the output of My, Next, message are blocking calls
   1. Meanwhile the next msgs Block Print and Block Print number 2 are done concurrently with goroutines.
   2. Also notice that the last goroutine called is the first message shown so they execute in reverse order

Go Routines Playground