Task

Create a temporary file, securely and exclusively (opening it such that there are no possible race conditions).

It's fine assuming local filesystem semantics (NFS or other networking filesystems can have signficantly more complicated semantics for satisfying the "no race conditions" criteria).

The function should automatically resolve name collisions and should only fail in cases where permission is denied, the filesystem is read-only or full, or similar conditions exist (returning an error or raising an exception as appropriate to the language/environment).




package main
 
import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
)
 
func main() {
	f, err := ioutil.TempFile("", "foo")
	if err != nil {
		log.Fatal(err)
	}
	defer f.Close()
 
	// We need to make sure we remove the file
	// once it is no longer needed.
	defer os.Remove(f.Name())
 
	// … use the file via 'f' …
	fmt.Fprintln(f, "Using temporary file:", f.Name())
	f.Seek(0, 0)
	d, err := ioutil.ReadAll(f)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("Wrote and read: %s\n", d)
 
        // The defer statements above will close and remove the
        // temporary file here (or on any return of this function).
}