How would you define a pool of goroutines to be executed at once?

Question

TL;DR: Please just go to the last part and tell me how you would solve this problem.

I\'ve begun using Go this morning coming from Python. I want to call a closed-sou

Answer 1

A simple approach to throttling (execute f() N times but maximum maxConcurrency concurrently), just a scheme:

package main

import (
        "sync"
)

const maxConcurrency = 4 // for example

var throttle = make(chan int, maxConcurrency)

func main() {
        const N = 100 // for example
        var wg sync.WaitGroup
        for i := 0; i < N; i++ {
                throttle <- 1 // whatever number
                wg.Add(1)
                go f(i, &wg, throttle)
        }
        wg.Wait()
}

func f(i int, wg *sync.WaitGroup, throttle chan int) {
        defer wg.Done()
        // whatever processing
        println(i)
        <-throttle
}

Playground

I wouldn't probably call the throttle channel "dummy". IMHO it's an elegant way (it's not my invention of course), how to limit concurrency.

BTW: Please note that you're ignoring the returned error from cmd.Run().