Re: [Qemu-devel] [PULL 14/15] qemu.py: improve message on negative exit code

["Daniel P. Berrange" <berrange@redhat.com>]

On Fri, Sep 15, 2017 at 08:37:38PM -0300, Eduardo Habkost wrote:
> From: Amador Pahim <apahim@redhat.com>
> 
> The current message shows 'self._args', which contains only part of the
> options used in the Qemu command line.
> 
> This patch makes the qemu full args list an instance variable and then
> uses it in the negative exit code message.
> 
> Message was moved outside the 'if is_running' block to make sure it will
> be logged if the VM finishes before the call to shutdown().
> 
> Signed-off-by: Amador Pahim <apahim@redhat.com>
> Message-Id: <20170901112829.2571-5-apahim@redhat.com>
> [ehabkost: removed superfluous parenthesis]
> Reviewed-by: Fam Zheng <famz@redhat.com>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  scripts/qemu.py | 24 +++++++++++++++++-------
>  1 file changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/scripts/qemu.py b/scripts/qemu.py
> index c9bcaafe41..9440261ac3 100644
> --- a/scripts/qemu.py
> +++ b/scripts/qemu.py
> @@ -87,6 +87,7 @@ class QEMUMachine(object):
>          self._socket_scm_helper = socket_scm_helper
>          self._debug = debug
>          self._qmp = None
> +        self._qemu_full_args = None
>  
>      def __enter__(self):
>          return self
> @@ -186,13 +187,16 @@ class QEMUMachine(object):
>  
>      def launch(self):
>          '''Launch the VM and establish a QMP connection'''
> +        self._qemu_full_args = None
>          devnull = open(os.path.devnull, 'rb')
>          qemulog = open(self._qemu_log_path, 'wb')
>          try:
>              self._pre_launch()
> -            args = (self._wrapper + [self._binary] + self._base_args() +
> -                    self._args)
> -            self._popen = subprocess.Popen(args, stdin=devnull, stdout=qemulog,
> +            self._qemu_full_args = self._wrapper + [self._binary] +
> +                                    self._base_args() + self._args

FYI, this change causes a syntax error because you need either the ()
brackets, or an explicit \ continuation. Unfortunately this wasn't
caught by Peter's merge tests, since this code is only execised by
the qemu iotests which aren't run from a 'make check'.

If someone has cycles, it would be great to write some unit tests
directly targetting the qemu.py and qmp.py code, so that we get test
coverage of it independantly of the iotest execution.

Regards,
Daniel
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