Re: [KVM AUTOTEST PATCH] [RFC] KVM test: keep record of supported qemu options

["Lukáš Doktor" <ldoktor@redhat.com>]

Hello Lucas,

I like your patch but I'm not entirely convinced about it necessity. 
Stable version of KVM should have this fixed and unstable ones are for 
developers, who are skilled enough to fix this using kvm_test.cfg.

On the other hand keep this patch somewhere. Eventually if qemu started 
to be naughty, we would have something useful in our pocket.

Best regards,
Lukáš

Dne 29.7.2009 05:40, Lucas Meneghel Rodrigues napsal(a):
> In order to make it easier to figure out problems and
> also to avoid aborting tests prematurely due to
> incompatible qemu options, keep record of supported
> qemu options, and if extra options are passed to qemu,
> verify if they are amongst the supported options. Also,
> try to replace known misspelings on options in case
> something goes wrong, and be generous logging any problems.
>
> This first version of the patch gets supported flags from
> the output of qemu --help. I thought this would be good
> enough for a first start. I am asking for input on whether
> this is needed, and if yes, if the approach looks good.
>
> Signed-off-by: Lucas Meneghel Rodrigues<lmr@redhat.com>
> ---
>   client/tests/kvm/kvm_vm.py |   79 ++++++++++++++++++++++++++++++++++++++++++-
>   1 files changed, 77 insertions(+), 2 deletions(-)
>
> diff --git a/client/tests/kvm/kvm_vm.py b/client/tests/kvm/kvm_vm.py
> index eba9b84..0dd34c2 100644
> --- a/client/tests/kvm/kvm_vm.py
> +++ b/client/tests/kvm/kvm_vm.py
> @@ -121,6 +121,7 @@ class VM:
>           self.qemu_path = qemu_path
>           self.image_dir = image_dir
>           self.iso_dir = iso_dir
> +        self.qemu_supported_flags = self.get_qemu_supported_flags()
>
>
>           # Find available monitor filename
> @@ -258,7 +259,7 @@ class VM:
>
>           extra_params = params.get("extra_params")
>           if extra_params:
> -            qemu_cmd += " %s" % extra_params
> +            qemu_cmd += " %s" % self.process_qemu_extra_params(extra_params)
>
>           for redir_name in kvm_utils.get_sub_dict_names(params, "redirs"):
>               redir_params = kvm_utils.get_sub_dict(params, redir_name)
> @@ -751,7 +752,7 @@ class VM:
>               else:
>                   self.send_key(char)
>
> -
> +
>       def get_uuid(self):
>           """
>           Catch UUID of the VM.
> @@ -762,3 +763,77 @@ class VM:
>               return self.uuid
>           else:
>               return self.params.get("uuid", None)
> +
> +
> +    def get_qemu_supported_flags(self):
> +        """
> +        Gets all supported qemu options from qemu-help. This is a useful
> +        procedure to quickly spot problems with incompatible qemu flags.
> +        """
> +        cmd = self.qemu_path + ' --help'
> +        (status, output) = kvm_subprocess.run_fg(cmd)
> +        supported_flags = []
> +
> +        if status:
> +            logging.error('Process qemu --help ended with exit code !=0. '
> +                          'No supported qemu flags will be recorded.')
> +            return supported_flags
> +
> +        for line in output.split('\n'):
> +            if line and line.startswith('-'):
> +                flag = line.split()[0]
> +                if flag not in supported_flags:
> +                    supported_flags.append(flag)
> +
> +        return supported_flags
> +
> +
> +    def process_qemu_extra_params(self, extra_params):
> +        """
> +        Verifies an extra param passed to qemu to see if it's supported by the
> +        current qemu version. If it's not supported, try to find an appropriate
> +        replacement on a list of known option misspellings.
> +
> +        @param extra_params: String with a qemu command line option.
> +        """
> +        flag = extra_params.split()[0]
> +
> +        if flag not in self.qemu_supported_flags:
> +            logging.error("Flag %s does not seem to be supported by the "
> +                          "current qemu version. Looking for a replacement...",
> +                          flag)
> +            supported_flag = self.get_qemu_flag_replacement(flag)
> +            if supported_flag:
> +                logging.debug("Replacing flag %s with %s", flag,
> +                              supported_flag)
> +                extra_params = extra_params.replace(flag, supported_flag)
> +            else:
> +                logging.error("No valid replacement was found for flag %s.",
> +                              flag)
> +
> +        return extra_params
> +
> +
> +    def get_qemu_flag_replacement(self, option):
> +        """
> +        Searches on a list of known misspellings for qemu options and returns
> +        a replacement. If no replacement can be found, return None.
> +
> +        @param option: String representing qemu option (such as -mem).
> +
> +        @return: Option replacement, or None, if none found.
> +        """
> +        list_mispellings = [['-mem-path', '-mempath'],]
> +        replacement = None
> +
> +        for mispellings in list_mispellings:
> +            if option in mispellings:
> +                option_position = mispellings.index(option)
> +                replacement = mispellings[1 - option_position]
> +
> +        if replacement not in self.qemu_supported_flags:
> +            logging.error("Replacement %s also does not seem to be a valid "
> +                          "qemu flag, aborting replacement.", replacement)
> +            return None
> +
> +        return replacement