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

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

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