Fix short-lived invocation-image exec (#606)

This reorders docker_driver operations, aligning with what does the docker CLI (attach, and setup wait channels before starting the container)

This fix an issue with very short lived image executions, where the container was removed before attaching/waiting for execution end.

Signed-off-by: Simon Ferquel <[email protected]>

pkg/driver/docker_driver.go

@@ -159,10 +159,6 @@ func (d *DockerDriver) exec(op *Operation) error {
 		return fmt.Errorf("error copying to / in container: %s", err)
 	}
 
-	if err = cli.Client().ContainerStart(ctx, resp.ID, types.ContainerStartOptions{}); err != nil {
-		return fmt.Errorf("cannot start container: %v", err)
-	}
-
 	attach, err := cli.Client().ContainerAttach(ctx, resp.ID, types.ContainerAttachOptions{
 		Stream: true,
 		Stdout: true,
@@ -182,16 +178,23 @@ func (d *DockerDriver) exec(op *Operation) error {
 		}
 	}()
 
-	statusc, errc := cli.Client().ContainerWait(ctx, resp.ID, container.WaitConditionNotRunning)
+	statusc, errc := cli.Client().ContainerWait(ctx, resp.ID, container.WaitConditionRemoved)
+	if err = cli.Client().ContainerStart(ctx, resp.ID, types.ContainerStartOptions{}); err != nil {
+		return fmt.Errorf("cannot start container: %v", err)
+	}
 	select {
 	case err := <-errc:
 		if err != nil {
 			return fmt.Errorf("error in container: %v", err)
 		}
-	case containerWaitOKBody := <-statusc:
-		if containerWaitOKBody.StatusCode != 0 {
-			return fmt.Errorf("container exited with status code: %v", containerWaitOKBody.StatusCode)
+	case s := <-statusc:
+		if s.StatusCode == 0 {
+			return nil
+		}
+		if s.Error != nil {
+			return fmt.Errorf("container exit code: %d, message: %v", s.StatusCode, s.Error.Message)
 		}
+		return fmt.Errorf("container exit code: %d", s.StatusCode)
 	}
 	return err
 }