Writing the file from multiple goroutines

This recipe will show you how to safely write to the file from multiple goroutines.

How to do it...

1. Open the console and create the folder chapter06/recipe04.
2. Navigate to the directory.
3. Create the syncwrite.go file with the following content:

        package main

        import (
          "fmt"
          "io"
          "os"
          "sync"
        )

        type SyncWriter struct {
          m sync.Mutex
          Writer io.Writer
        }

        func (w *SyncWriter) Write(b []byte) (n int, err error) {
          w.m.Lock()
          defer w.m.Unlock()
          return w.Writer.Write(b)
        }

        var data = []string{
          "Hello!",
          "Ola!",
          "Ahoj!",
        }

        func main() {

          f, err := os.Create("sample.file")
          if err != nil {
            panic(err)
          }

          wr := &SyncWriter{sync.Mutex{}, f}
          wg := sync.WaitGroup{}
          for _, val := range data {
      ...