github.com/smithx10/nomad@v0.9.1-rc1/client/lib/fifo/fifo_unix.go (about)

     1  // +build !windows
     2  
     3  package fifo
     4  
     5  import (
     6  	"fmt"
     7  	"io"
     8  	"os"
     9  
    10  	"golang.org/x/sys/unix"
    11  )
    12  
    13  // CreateAndRead creates a fifo at the given path, and returns an open function for reading.
    14  // The fifo must not exist already, or that it's already a fifo file
    15  //
    16  // It returns a reader open function that may block until a writer opens
    17  // so it's advised to run it in a goroutine different from reader goroutine
    18  func CreateAndRead(path string) (func() (io.ReadCloser, error), error) {
    19  	// create first
    20  	if err := mkfifo(path, 0600); err != nil && !os.IsExist(err) {
    21  		return nil, fmt.Errorf("error creating fifo %v: %v", path, err)
    22  	}
    23  
    24  	openFn := func() (io.ReadCloser, error) {
    25  		return os.OpenFile(path, unix.O_RDONLY, os.ModeNamedPipe)
    26  	}
    27  
    28  	return openFn, nil
    29  }
    30  
    31  // OpenWriter opens a fifo file for writer, assuming it already exists, returns io.WriteCloser
    32  func OpenWriter(path string) (io.WriteCloser, error) {
    33  	return os.OpenFile(path, unix.O_WRONLY, os.ModeNamedPipe)
    34  }
    35  
    36  // Remove a fifo that already exists at a given path
    37  func Remove(path string) error {
    38  	return os.Remove(path)
    39  }
    40  
    41  func IsClosedErr(err error) bool {
    42  	err2, ok := err.(*os.PathError)
    43  	if ok {
    44  		return err2.Err == os.ErrClosed
    45  	}
    46  	return false
    47  }
    48  
    49  func mkfifo(path string, mode uint32) (err error) {
    50  	return unix.Mkfifo(path, mode)
    51  }