Merge pull request #138 from harshavardhana/pr_out_add_simple_execpipe_to_be_used_with_filesystem_format_work

Add simple ExecPipe() to be used with filesystem format work
master
Harshavardhana 10 years ago
commit d1fe8beff5
  1. 46
      pkgs/utils/execpipe.go
  2. 34
      pkgs/utils/execpipe_test.go

@ -0,0 +1,46 @@
package utils
import (
"bytes"
"errors"
"os/exec"
)
// A simple ExecPipe() pipes exec.Cmd together - somewhat similar to how bash pipes "|" behave.
// Each command's standard output is connected to the standard input of the next command
// and the output of the final command is returned
func ExecPipe(cmds ...*exec.Cmd) (pipeLineOutput []byte, pipeLineError error) {
// Require at least one command
if len(cmds) < 1 {
return nil, errors.New("Invalid argument")
}
// Collect the output from the command(s)
var output bytes.Buffer
lastIndex := len(cmds) - 1
for i, cmd := range cmds[:lastIndex] {
cmds[i+1].Stdin, _ = cmd.StdoutPipe()
}
// Final ---> output buffer
cmds[lastIndex].Stdout = &output
// Start each command
for _, cmd := range cmds {
if err := cmd.Start(); err != nil {
return output.Bytes(), err
}
}
// We should Wait() for each command to complete
for _, cmd := range cmds {
if err := cmd.Wait(); err != nil {
return output.Bytes(), err
}
}
// Return the output
return output.Bytes(), nil
}

@ -0,0 +1,34 @@
// !build linux,amd64
package utils
import (
. "gopkg.in/check.v1"
"os/exec"
"testing"
)
type MySuite struct{}
var _ = Suite(&MySuite{})
func Test(t *testing.T) { TestingT(t) }
func (s *MySuite) TestPiping(c *C) {
// Collect directories from the command-line
dirs := []string{"."}
// Run the command on each directory
for _, dir := range dirs {
// find $DIR -type f # Find all files
ls := exec.Command("ls", dir, "-l")
// | sort -t. -k2 # Sort by file extension
sort := exec.Command("sort", "-t.", "-k2")
// Run
output, err := ExecPipe(ls, sort)
c.Assert(err, IsNil)
c.Assert(len(output), Not(Equals), 0)
}
}
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