Properly report when command reached timeout (#101)

Before this we just reported that the process was killed, but not that
the kill signal was triggered by the timeout.

Author: mrnugget

cmd/src/actions_exec_backend_runner.go

@@ -86,7 +86,7 @@ func (x *actionExecutor) do(ctx context.Context, repo ActionRepo) (err error) {
 		}
 	}
 	if err != nil {
-		if errors.Cause(err) == context.DeadlineExceeded {
+		if reachedTimeout(runCtx, err) {
 			err = &errTimeoutReached{timeout: x.opt.timeout}
 		}
 		status.Err = err
@@ -112,6 +112,16 @@ func (e *errTimeoutReached) Error() string {
 	return fmt.Sprintf("Timeout reached. Execution took longer than %s.", e.timeout)
 }
 
+func reachedTimeout(cmdCtx context.Context, err error) bool {
+	if ee, ok := errors.Cause(err).(*exec.ExitError); ok {
+		if ee.String() == "signal: killed" && cmdCtx.Err() == context.DeadlineExceeded {
+			return true
+		}
+	}
+
+	return errors.Is(err, context.DeadlineExceeded)
+}
+
 func runAction(ctx context.Context, prefix, repoID, repoName, rev string, steps []*ActionStep, logFile io.Writer) ([]byte, error) {
 	fmt.Fprintf(logFile, "# Repository %s @ %s (%d steps)\n", repoName, rev, len(steps))