[Kimchi-devel] [PATCH V2] Avoid useless libvirt error log produced by featuretests

[Aline Manera]

On 01/23/2014 08:16 AM, apporc wrote:
> When running feature tests, we get bunch of error messages as below:
>
> *** Running feature tests ***
> libvirt: Domain Config error : internal error unknown protocol type 'http'
> libvirt: Domain Config error : internal error unknown protocol type 'https'
> libvirt: Domain Config error : internal error unknown protocol type 'ftp'
> libvirt: Domain Config error : internal error unknown protocol type 'ftps'
> libvirt: Domain Config error : internal error unknown protocol type 'tftp'
> *** Feature tests completed ***
>
> By replacing default error handler of libvirt, this patch succeeded to
> avoid the error. After Featuretest, the default error handler will be restored.
> The default error handler(in libvirtmod.so) just do one thing, it prints the error message to
> stderr before we catch the exception in python.
>
> Signed-off-by: apporc <appleorchard2000 at gmail.com>
> ---
>   src/kimchi/featuretests.py |   14 ++++++++++++--
>   1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/src/kimchi/featuretests.py b/src/kimchi/featuretests.py
> index a5755a2..d68fcb8 100644
> --- a/src/kimchi/featuretests.py
> +++ b/src/kimchi/featuretests.py
> @@ -57,16 +57,26 @@ class FeatureTests(object):
>
>       @staticmethod
>       def libvirt_supports_iso_stream(protocol):
> +        def libvirt_errorhandler(userdata, error):
> +            # A libvirt error handler to ignore annoying messages in stderr
> +            pass
> +
>           xml = ISO_STREAM_XML % {'protocol': protocol}
>           conn = None
>           try:
> +            # Register the error handler to hide libvirt error in stderr
> +            libvirt.registerErrorHandler(f=libvirt_errorhandler, ctx=None)
>               conn = libvirt.open('qemu:///system')
>               dom = conn.defineXML(xml)
>               dom.undefine()
>               return True
> -        except libvirt.libvirtError:
> -            return False

> +        except libvirt.libvirtError, e:
> +            if e.message == "internal error unknown protocol type '%s'" % protocol:
> +                return False
> +            else:
> +                raise e

Independent of the exception we should not raise it.
It is a feature test, so if something failed we just return 'False' and 
backend will handle it correctly.

>           finally:
> +            libvirt.registerErrorHandler(f=None, ctx=None)
>               conn is None or conn.close()
>
>       @staticmethod