Re: [Pytables-users] New find_library('hdf5dll.dll') call fails in frozen app

[Stuart M. <Stu...@ob...>]

On 8/27/2012 2:45 PM, Christoph Gohlke wrote:
> On 8/27/2012 10:58 AM, Stuart Mentzer wrote:
>> On 8/27/2012 1:22 PM, Christoph Gohlke wrote:
>>> On 8/27/2012 9:42 AM, Antonio Valentino wrote:
>>>> Hi Stuart,
>>>>
>>>> Il 27/08/2012 17:43, Stuart Mentzer ha scritto:
>>>>> Hello,
>>>>>
>>>>> I upgraded to PyTables 2.4.0 and I was "freezing" an application on Windows with PyInstaller. The frozen app fails at this new find_library call in __init__.py:
>>>>>
>>>>>           if not ctypes.util.find_library('hdf5dll.dll'):
>>>>>               raise ImportError('Could not load "hdf5dll.dll", please ensure' +
>>>>>                       ' that it can be found in the system path')
>>>>>
>>>>> PyInstaller correctly places this DLL in the same directory as the application .exe where standard Windows DLL search logic will find it. Apparently the find_library doesn't do that in a frozen application. That is a big problem. I had to comment this code out to get a working frozen app.
>>>>>
>>>>> That code was added in revision e9f6919.
>>>>>
>>>> It is mainly a sanity check added under request of one of our users:
>>>> https://github.com/PyTables/PyTables/pull/146
>>>>
>>>>
>>>>> This is on Windows 7 64-bit with a 32-bit Python toolchain. Trying both PyInstaller 1.5.1 and 2.0.
>>>>>
>>>>> Should I file a bug report? Any easy work-around?
>>>>>
>>>>> Thanks,
>>>>> Stuart
>>>>>
>>>> Yes please file a pull request with your patch.
>>>> It would be nice to preserve the sanity check in standard case so,
>>>> maybe, a good solution could be adding some check on sys.frozen or
>>>> something like that.
>>>>
>>>> Thank you
>>>>
>>> Hello,
>>>
>>> As a workaround for frozen distributions, try to add the sys.executable
>>> directory to os.environ['PATH'] before importing tables.
>>>
>>> Ctypes only tries to find a library in the os.environ['PATH']
>>> directories, not the current directory or the sys.executable directory
>>> as one could expect.
>>> http://hg.python.org/cpython/file/64640a02b0ca/Lib/ctypes/util.py#l48
>>>
>>> As a workaround, for distributions that place the HDF5 and other DLLs in
>>> the tables package directory, tables.__init__.py adds the tables package
>>> directory to os.environ['PATH']. This also makes sure that the DLLs are
>>> found when loading the hdf5Extension.pyd and other C extension modules
>>> (another common problem). The use of __file__ to get the tables
>>> directory should better be wrapped in a try..except statement.
>>> https://github.com/PyTables/PyTables/blob/develop/tables/__init__.py#L24
>>>
>>> Christoph
>> Hi Christoph,
>>
>> Thanks for the info/suggestions. It might be nice to add your comments to the
>> Issue #177 I created.
>>
>> I was aware that altering the PATH is a work-around. Patching PyTables is cleaner
>> and seems like the proper fix, and I think we agree that there is a problem here
>> that should be addressed. Maybe the PyTables test suite should even include a
>> frozen application test.
>>
>> Thanks,
>> Stuart
>>
> Hi Stuart,
>
> I'll try to work on a patch tonight. It's probably better to use Ctypes
> LoadLibrary instead of find_library because that makes sure all HDF5
> dependencies are found, it (supposedly) searches the Windows DLL search
> path not just os.environ['PATH'], and (supposedly) takes into account
> libraries already loaded into the process.
>
> Christoph
Great. I'll be happy to test a patch in the frozen context.

Stuart