func (r *runner) Map(mr *simplemr.MR, key string, val interface{}) error {
mi := val.(*mapInput)
output := &mapOutput{
key: key,
mi: mi}
jirix := mi.jirix
path := os.Getenv("SHELL")
if path == "" {
path = "sh"
}
var wg sync.WaitGroup
cmd := exec.Command(path, "-c", strings.Join(r.args, " "))
cmd.Env = envvar.MapToSlice(jirix.Env())
cmd.Dir = mi.ProjectState.Project.Path
cmd.Stdin = mi.jirix.Stdin()
var stdoutCloser, stderrCloser io.Closer
if runpFlags.interactive {
cmd.Stdout = jirix.Stdout()
cmd.Stderr = jirix.Stderr()
} else {
var stdout io.Writer
stderr := r.serializedWriter(jirix.Stderr())
var cleanup func()
if runpFlags.collateOutput {
// Write standard output to a file, stderr
// is not collated.
f, err := ioutil.TempFile("", mi.ProjectState.Project.Name+"-")
if err != nil {
return err
}
stdout = f
output.outputFilename = f.Name()
cleanup = func() {
os.Remove(output.outputFilename)
}
// The child process will have exited by the
// time this method returns so it's safe to close the file
// here.
defer f.Close()
} else {
stdout = r.serializedWriter(jirix.Stdout())
cleanup = func() {}
}
if !runpFlags.showNamePrefix && !runpFlags.showKeyPrefix {
// write directly to stdout, stderr if there's no prefix
cmd.Stdout = stdout
cmd.Stderr = stderr
} else {
stdoutReader, stdoutWriter, err := os.Pipe()
if err != nil {
cleanup()
return err
}
stderrReader, stderrWriter, err := os.Pipe()
if err != nil {
cleanup()
stdoutReader.Close()
stdoutWriter.Close()
return err
}
cmd.Stdout = stdoutWriter
cmd.Stderr = stderrWriter
// Record the write end of the pipe so that it can be closed
// after the child has exited, this ensures that all goroutines
// will finish.
stdoutCloser = stdoutWriter
stderrCloser = stderrWriter
prefix := key
if runpFlags.showNamePrefix {
prefix = mi.ProjectState.Project.Name
}
wg.Add(2)
go func() { copyWithPrefix(prefix, stdout, stdoutReader); wg.Done() }()
go func() { copyWithPrefix(prefix, stderr, stderrReader); wg.Done() }()
}
}
if err := cmd.Start(); err != nil {
mi.result = err
}
done := make(chan error)
go func() {
done <- cmd.Wait()
}()
select {
case output.err = <-done:
if output.err != nil && runpFlags.exitOnError {
mr.Cancel()
}
case <-mr.CancelCh():
output.err = cmd.Process.Kill()
}
for _, closer := range []io.Closer{stdoutCloser, stderrCloser} {
if closer != nil {
closer.Close()
}
}
wg.Wait()
mr.MapOut(key, output)
return nil
}
