Add a library for running external commands, providing timeouts and test injection.

go/util/command.go

Index: go/util/command.go
diff --git a/go/util/command.go b/go/util/command.go
index f1494ad1d891b28b85d970851c1599102f553426..48db07892cc9688d8860fd01ff5df53467ff42f0 100644
--- a/go/util/command.go
+++ b/go/util/command.go
@@ -1,31 +1,12 @@
 package util
 
 import (
-	"os/exec"
-	"strings"
-
-	"github.com/skia-dev/glog"
+	"go.skia.org/infra/go/exec"
 )
 
 // DoCmd executes the given command line string; the command being
 // run is expected to not care what its current working directory is.
-// Returns the stdout and stderr.  If there is an error, the
-// returned error will be of type ExitError, which the caller
-// can use to find out more about what happened.
+// Returns the stdout and stderr.
 func DoCmd(commandLine string) (string, error) {
-	glog.Infof("Command: %q\n", commandLine)
-	programAndArgs := strings.SplitN(commandLine, " ", 2)
-	program := programAndArgs[0]
-	args := []string{}
-	if len(programAndArgs) > 1 {
-		args = strings.Split(programAndArgs[1], " ")
-	}
-	cmd := exec.Command(program, args...)
-	message, err := cmd.CombinedOutput()
-	glog.Infof("StdOut + StdErr: %s\n", string(message))
-	if err != nil {
-		glog.Errorf("Exit status: %s\n", err)
-		return string(message), err
-	}
-	return string(message), nil
+	return exec.RunSimple(commandLine)
 }