[gdal-dev] Motion: adopt RFC 96: Deferred C++ plugin loading

[Robert Coup]

Hi Sean

On Thu, 16 Nov 2023 at 12:10, Even Rouault via gdal-dev <
gdal-dev at lists.osgeo.org> wrote:

> >
> > I think this makes great sense for the project. I don't yet understand
> > what it means for an enterprise like Rasterio's PyPI wheels.
>
> I'd say it probably changes nothing. The RFC just postpones the time
> where the plugins are loaded, but the fact that they are dlopen()'ed
> (early or late) probably makes them non discoverable by delocate, since
> libgdal doesn't link to them in a way that is advertised in its shared
> library metadata. If your plan is to still have a rasterio wheel with a
> monolithic GDAL, then you don't need to build GDAL drivers as plugins
> and this RFC doesn't change anything to the status quo.
>
> I'm not familiar at all with the wheel Python packaging tools, but if
> you'd want to have GDAL plugins in separate package(s) then you'd need
> to have a way of having the gdal_XXX.so / ogr_XXX.so be put in some
> known location that can be advertized to libgdal core with
> GDAL_DRIVER_PATH.
>

PyInstaller has a set of hooks for this, where custom behaviour can be
scripted for packages that need it. AFAICS auditwheel & delocate don't, and
also don't have `--include=my.so` options to override it and "force"
libraries to be processed — the same issue crops up for stuff using ctypes
IIUC.

My horrible workaround idea: building a shim _gdalplugins python module
which does nothing except link to all the plugin libraries — that would
allow them all to be processed by delocate/auditwheel alongside the real
libgdal — so you get libgdal, and all the driver plugin libraries, and
their dependencies. Since _gdalplugins is never used/loaded (ideally it'd
be dropped) gdal would work via runtime plugin loading. The library
renaming that auditwheel/delocate do might get in the way, but hopefully
there's a path through that.

Cheers,

Rob :)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20231116/246ca449/attachment.htm>