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

[Christoph G. <cg...@uc...>]

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