Re: [Qemu-devel] [PATCH] qemu.py: Call logging.basicConfig() automatically

[Cleber Rosa]

On 09/21/2017 12:22 PM, Eduardo Habkost wrote:
> Not all scripts using qemu.py configure the Python logging
> module, and end up generating a "No handlers could be found for
> logger" message instead of actual log messages.
> 
> To avoid requiring every script using qemu.py to configure
> logging manually, call basicConfig() when creating a QEMUMachine
> object.  This won't affect scripts that already set up logging,
> but will ensure that scripts that don't configure logging keep
> working.
> 
> Reported-by: Kevin Wolf <address@hidden>
> Fixes: 4738b0a85a0c2031fddc71b51cccebce0c4ba6b1
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
>  scripts/qemu.py | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/scripts/qemu.py b/scripts/qemu.py
> index 5e02dd8e78..73d6031e02 100644
> --- a/scripts/qemu.py
> +++ b/scripts/qemu.py
> @@ -89,6 +89,9 @@ class QEMUMachine(object):
>          self._qmp = None
>          self._qemu_full_args = None
>  
> +        # just in case logging wasn't configured by the main script:
> +        logging.basicConfig(level=(logging.DEBUG if debug else logging.WARN))
> +
>      def __enter__(self):
>          return self
>  
> 

Your description is accurate, and backed by:

https://docs.python.org/3/library/logging.html#logging.basicConfig

Quoting the relevant section: "This function does nothing if the root
logger already has handlers configured for it."

Reviewed-by: Cleber Rosa <address@hidden>