Go Standard Library Cookbook

How to do it...

1. Open the console and create the folder chapter10/recipe04.
2. Navigate to the directory.
3. Create the file pool.go with the following content:

        package main        import "sync"        import "fmt"        import "time"        type Worker struct {          id string        }        func (w *Worker) String() string {          return w.id        }        var globalCounter = 0        var pool = sync.Pool{          New: func() interface{} {            res := &Worker{fmt.Sprintf("%d", globalCounter)}            globalCounter++            return res          },        }        func main() {          wg := &sync.WaitGroup{}          wg.Add(10)          for i := 0; i < 10; i++ {            go func(idx int) {              // This code block is done only once              w := pool.Get().(*Worker)              fmt.Println("Got worker ID: " + w.String())              time.Sleep(time.Second)              pool.Put(w)              wg.Done()            }(i)          }          wg.Wait()        }

4. Execute the code by go run pool.go.