Add new "execpipe" package for easily streaming the output of commands in a sane, simple "io.Reader" way

pkg/execpipe/execpipe.go

@@ -0,0 +1,41 @@
+package execpipe
+
+import (
+	"io"
+	"os/exec"
+)
+
+// "io.ReadCloser" interface to a command's output where "Close()" is effectively "Wait()"
+type Pipe struct {
+	cmd *exec.Cmd
+	out io.ReadCloser
+}
+
+// convenience wrapper for "New"
+func NewCommand(cmd string, args ...string) (*Pipe, error) {
+	return New(exec.Command(cmd, args...))
+}
+
+// start "cmd", capturing stdout in a pipe (be sure to call "Close" when finished reading to reap the process)
+func New(cmd *exec.Cmd) (*Pipe, error) {
+	p := &Pipe{
+		cmd: cmd,
+	}
+	var err error
+	if p.out, err = p.cmd.StdoutPipe(); err != nil {
+		return nil, err
+	}
+	if err := p.cmd.Start(); err != nil {
+		p.out.Close()
+		return nil, err
+	}
+	return p, nil
+}
+
+func (pipe *Pipe) Read(p []byte) (n int, err error) {
+	return pipe.out.Read(p)
+}
+
+func (p *Pipe) Close() error {
+	return p.cmd.Wait()
+}