[libcamera-devel] [RFC v1 2/7] py: Add Python logging category

[Tomi Valkeinen]

On 24/06/2022 12:50, Laurent Pinchart wrote:
> Hi Tomi,
> 
> Thank you for the patch.
> 
> On Thu, Jun 23, 2022 at 05:47:31PM +0300, Tomi Valkeinen wrote:
>> Add Python logging category, and use it in handleRequestCompleted().
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>
>> ---
>>   src/py/libcamera/py_main.cpp |  8 ++++++--
>>   src/py/libcamera/py_main.h   | 12 ++++++++++++
>>   2 files changed, 18 insertions(+), 2 deletions(-)
>>   create mode 100644 src/py/libcamera/py_main.h
>>
>> diff --git a/src/py/libcamera/py_main.cpp b/src/py/libcamera/py_main.cpp
>> index 505cc3dc..17b17f60 100644
>> --- a/src/py/libcamera/py_main.cpp
>> +++ b/src/py/libcamera/py_main.cpp
>> @@ -5,6 +5,8 @@
>>    * Python bindings
>>    */
>>   
>> +#include "py_main.h"
>> +
>>   #include <mutex>
>>   #include <stdexcept>
>>   #include <sys/eventfd.h>
>> @@ -23,6 +25,8 @@ namespace py = pybind11;
>>   
>>   using namespace libcamera;
>>   
>> +LOG_DEFINE_CATEGORY(Python)
>> +
>>   template<typename T>
>>   static py::object valueOrTuple(const ControlValue &cv)
>>   {
>> @@ -120,10 +124,10 @@ static void handleRequestCompleted(Request *req)
>>   	size_t s = write(gEventfd, &v, 8);
>>   	/*
>>   	 * We should never fail, and have no simple means to manage the error,
>> -	 * so let's use LOG(Fatal).
>> +	 * so let's use LOG(Python, Fatal).
> 
> You could also write "so let's log a fatal error".

Yep.

>>   	 */
>>   	if (s != 8)
>> -		LOG(Fatal) << "Unable to write to eventfd";
>> +		LOG(Python, Fatal) << "Unable to write to eventfd";
>>   }
>>   
>>   void init_py_enums(py::module &m);
>> diff --git a/src/py/libcamera/py_main.h b/src/py/libcamera/py_main.h
>> new file mode 100644
>> index 00000000..1b543a55
>> --- /dev/null
>> +++ b/src/py/libcamera/py_main.h
>> @@ -0,0 +1,12 @@
>> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
>> +/*
>> + * Copyright (C) 2022, Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>
>> + */
>> +
>> +#pragma once
>> +
>> +#include <libcamera/base/log.h>
>> +
>> +using namespace libcamera;
> 
> "using namespace" directives are discouraged in header files, as they
> will propagate to all compilation units. Could this be avoided ? With
> that fixed,

LOG_DECLARE_CATEGORY() requires either using namespace or being inside 
libcamera namespace.

I guess I could move all the python bindings code to be inside libcamera 
namespace. Then again, these are bindings internal headers and as such 
the using namespace should cause no issues.

  Tomi