Just wanted to give a quick +1 here, came in handy for a use-case just now!
On Sunday, July 3, 2016 at 4:00:25 PM UTC-4, soapboxcicero wrote:
>
> Sorry for bumping an oldish thread, but I just ran into this trying to
> propagate an exit code.
>
> I didn't find anything searching that was sufficiently
> platform-independent, but a little spelunking into the stdlib source
> bore fruit, so I thought I'd share my solution.
>
> If you have an *exec.ExitError it embeds an *os.ProcessState.
>
> *os.ProcessState's Sys method returns an interface{} containing the a
> platform specific type from the syscall package.
>
> But all the platform specific types have a method ExitStatus() int.
> (Even nacl and Plan 9, which fake it).
>
> So, given an *exec.ExitError x, to get the exit code you just need to do:
>
> exitCode := x.Sys().(interface{
> ExitStatus() int
> }).ExitStatus()
>
> I suppose it wouldn't hurt to check that type assertion and return -1
> if it fails, though I imagine if that ever happened it would be a bug
> in a new port.
>
>
> On Thu, Jun 2, 2016 at 4:14 AM, Konstantin Khomoutov
> <flat...@users.sourceforge.net <javascript:>> wrote:
> > On Wed, 1 Jun 2016 23:56:43 +0300
> > Janne Snabb <sn...@epipe.com <javascript:>> wrote:
> >
> >> You should check if the type of err is *exec.ExitError and in that
> >> case consider it just as non-zero exit value from the process.
> >>
> >> The following snippet from
> >> https://golang.org/src/os/exec/exec_test.go#L123 clarifies it:
> >>
> >> func TestExitStatus(t *testing.T) {
> >> // Test that exit values are returned correctly
> >> cmd := helperCommand(t, "exit", "42")
> >> err := cmd.Run()
> >> want := "exit status 42"
> >>
> >> if werr, ok := err.(*exec.ExitError); ok {
> >> if s := werr.Error(); s != want {
> >> t.Errorf("from exit 42 got exit %q, want %q",
> >> s, want) }
> >> } else {
> >> t.Fatalf("expected *exec.ExitError from exit 42; got %
> >> T: %v", err, err) }
> >> }
> >
> > I'd warn the OP to take this snippet with a hefty grain of salt: while
> > it's perfectly reasonable for the test suite of an stdlib package to
> > test the output of os/exec.ExitError.Error(), 3rd-party code must not
> > rely on the output of the Error() methods of error values of any type to
> > be predictable and stable -- at least until there's absolutely no
> > other way to get onto error's details.
> >
> > That is, the OP should consider writing a helper function to test the
> > error returned by os/exec.Cmd.Run() et al to check whether the exit
> > status is non-zero and discard the error value if so.
> >
> > An example:
> >
> > ----8<----
> > package main
> >
> > import (
> > "os/exec"
> > "testing"
> > )
> >
> > func maybeIgnore(err error) error {
> > if _, ok := err.(*exec.ExitError); ok {
> > return nil
> > }
> > return err
> > }
> >
> > func TestExitCode(t *testing.T) {
> > cmd := exec.Command("/bin/sh", "-c", "exit 42")
> > err := maybeIgnore(cmd.Run())
> > if err != nil {
> > t.Error("Expected nil error, got: %#v", err)
> > }
> > cmd = exec.Command("./does not exist, really")
> > err = maybeIgnore(cmd.Run())
> > if err == nil {
> > t.Error("Expected non-nil error, got nil")
> > }
> > }
> > ----8<----
> >
> > (Save as "whatever_test.go" and run `go test`.)
> >
> > --
> > You received this message because you are subscribed to the Google
> Groups "golang-nuts" group.
> > To unsubscribe from this group and stop receiving emails from it, send
> an email to golang-nuts...@googlegroups.com <javascript:>.
> > For more options, visit https://groups.google.com/d/optout.
>
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
