Improving error messages in windows command execution (#2054)

improving error messages from executing commands on windows

platform/os_windows.go

@@ -16,6 +16,7 @@ import (
 	"github.com/Azure/azure-container-networking/log"
 	"github.com/Azure/azure-container-networking/platform/windows/adapter"
 	"github.com/Azure/azure-container-networking/platform/windows/adapter/mellanox"
+	"github.com/pkg/errors"
 	"golang.org/x/sys/windows"
 )
 
@@ -108,20 +109,19 @@ func GetLastRebootTime() (time.Time, error) {
 }
 
 func (p *execClient) ExecuteCommand(command string) (string, error) {
-	log.Printf("[Azure-Utils] %s", command)
+	log.Printf("[Azure-Utils] ExecuteCommand: %q", command)
+
+	var stderr, stdout bytes.Buffer
 
-	var stderr bytes.Buffer
-	var out bytes.Buffer
 	cmd := exec.Command("cmd", "/c", command)
 	cmd.Stderr = &stderr
-	cmd.Stdout = &out
+	cmd.Stdout = &stdout
 
-	err := cmd.Run()
-	if err != nil {
-		return "", fmt.Errorf("%s:%s", err.Error(), stderr.String())
+	if err := cmd.Run(); err != nil {
+		return "", errors.Wrapf(err, "ExecuteCommand failed. stdout: %q, stderr: %q", stdout.String(), stderr.String())
 	}
 
-	return out.String(), nil
+	return stdout.String(), nil
 }
 
 func SetOutboundSNAT(subnet string) error {

platform/os_windows_test.go

@@ -2,11 +2,13 @@ package platform
 
 import (
 	"errors"
+	"os/exec"
 	"testing"
 
 	"github.com/Azure/azure-container-networking/platform/windows/adapter/mocks"
 	"github.com/golang/mock/gomock"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 var errTestFailure = errors.New("test failure")
@@ -81,3 +83,18 @@ func TestUpdatePriorityVLANTagIfRequiredIfCurrentValNotEqualDesiredValAndSetRetu
 	result := updatePriorityVLANTagIfRequired(mockNetworkAdapter, 5)
 	assert.EqualError(t, result, "error while setting Priority VLAN Tag value: test failure")
 }
+
+func TestExecuteCommand(t *testing.T) {
+	out, err := NewExecClient().ExecuteCommand("dir")
+	require.NoError(t, err)
+	require.NotEmpty(t, out)
+}
+
+func TestExecuteCommandError(t *testing.T) {
+	_, err := NewExecClient().ExecuteCommand("dontaddtopath")
+	require.Error(t, err)
+
+	var xErr *exec.ExitError
+	assert.ErrorAs(t, err, &xErr)
+	assert.Equal(t, 1, xErr.ExitCode())
+}