tools/src/utils/run_concurrent.go

// Copyright 2022 The Dawn & Tint Authors
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package utils

import "sync"

// RunConcurrent calls fn on numRoutines separate go routines.
// RunConcurrent will return on the first error returned, leaving the other go
// routines to complete.
func RunConcurrent(numRoutines int, fn func() error) error {
	errs := make(chan error, numRoutines)
	wg := sync.WaitGroup{}
	wg.Add(numRoutines)
	for i := 0; i < numRoutines; i++ {
		go func() {
			defer wg.Done()
			errs <- fn()
		}()
	}
	go func() {
		wg.Wait()
		close(errs)
	}()
	for err := range errs {
		if err != nil {
			return err
		}
	}
	return nil
}