Hi Tim,
UseExceptions() might only affect your main thread. You may want to check
in GDAL's code to see if this is the case. At any rate, you won't be able
to handle Python exceptions that you might see raised from the warp threads.
Hope this helps,
On Sat, Mar 1, 2025 at 11:30 AM Tim Harris via gdal-dev <
gdal-dev@lists.osgeo.org> wrote:
> Aha, yes, it does appear to happen just with local files. In my attempts
> to create a reproduce case yesterday, I overlooked that part. I did try it
> early on but just with a single TIF in the VRT, in which case it does the
> right thing and raises an exception. But with two TIFs and one missing, it
> behaves as I explained with /vsis3.
>
> So create two TIFs and a VRT, then remove one TIF:
> gdal_create -of GTiff -outsize 1000 1000 -bands 1 -a_srs EPSG:4326 -a_ullr
> 0 1 1 0 input1.tif
> gdal_create -of GTiff -outsize 1000 1000 -bands 1 -a_srs EPSG:4326 -a_ullr
> 1 1 2 0 input2.tif
> gdalbuildvrt input.vrt input1.tif input2.tif
> rm input2.tif
>
> Then in Python:
> from osgeo import gdal
> gdal.UseExceptions()
>
> This raises an exception
> gdal.Warp("output.tif", "input.vrt", callback=gdal.TermProgress)
>
> But this does not:
> gdal.Warp("output.tif", "input.vrt", callback=gdal.TermProgress,
> multithread=True)
>
>
> On Sat, Mar 1, 2025 at 7:58 AM Javier Jimenez Shaw <j...@jimenezshaw.com>
> wrote:
>
>> Does it also happen without S3, just with local files?
>> It would simplify the analysis
>>
>> On Sat, 1 Mar 2025, 01:01 Tim Harris via gdal-dev, <
>> gdal-dev@lists.osgeo.org> wrote:
>>
>>> Hi, I'm having some trouble warping a VRT to a TIF where the VRT and its
>>> constituent rasters are in S3. It stems from a random read error, but the
>>> real problem is that the gdal.Warp call didn't throw an exception when it
>>> was supposed to.
>>>
>>> I saw there's this pretty old GitHub issue that may be related, but I'm
>>> not sure:
>>> https://github.com/OSGeo/gdal/issues/3372
>>>
>>> In my situation what really happened was a random /vsicurl read
>>> failed... sort of like an issue I reported in December that was fixed in
>>> GDAL 3.10.1:
>>> https://github.com/OSGeo/gdal/issues/11552
>>>
>>> Here's a section of my log file (filename sanitized):
>>> ERROR 11: CURL error: Empty reply from server
>>> 0...10...20...30...40...50...60...70...80...90...100 - done.
>>> ERROR 4: `/vsis3/path/to/raster.tif' does not exist in the file system,
>>> and is not recognized as a supported dataset name.
>>>
>>> Notice the CURL error but the progress still goes to 100%. The warp
>>> completed successfully despite the read error.
>>>
>>> I have a hopefully simple reproduce case here. The first few shell
>>> commands will make two TIFs, put them in S3, then make a VRT of those TIFs
>>> and also put that in S3. Then to simulate the CURL error above, it just
>>> deletes one of the TIFs so that the VRT references a non-existent file:
>>> gdal_create -of GTiff -outsize 1000 1000 -bands 1 -a_srs EPSG:4326
>>> -a_ullr 0 1 1 0 input1.tif
>>> gdal_create -of GTiff -outsize 1000 1000 -bands 1 -a_srs EPSG:4326
>>> -a_ullr 1 1 2 0 input2.tif
>>> aws s3 cp input1.tif s3://your-bucket/test/input1.tif
>>> aws s3 cp input2.tif s3://your-bucket/test/input2.tif
>>> gdalbuildvrt input.vrt /vsis3/your-bucket/test/input1.tif
>>> /vsis3/your-bucket/test/input2.tif
>>> aws s3 cp input.vrt s3://your-bucket/test/input.vrt
>>> aws s3 rm s3://your-bucket/test/input2.tif
>>>
>>> Then in Python:
>>> from osgeo import gdal
>>> gdal.UseExceptions()
>>> gdal.Warp("output.tif", "/vsis3/tharris-bucket/test/input.vrt",
>>> callback=gdal.TermProgress)
>>>
>>> This throws a RuntimeError, as expected. But delete the partial file and
>>> try with multithread=True:
>>> rm output.tif
>>> gdal.Warp("output.tif", "/vsis3/tharris-bucket/test/input.vrt",
>>> callback=gdal.TermProgress, multithread=True)
>>>
>>> This logs the error, but doesn't throw an exception. The end result is
>>> that I have a TIF that is missing the contents of the file that suffered
>>> from that CURL read error.
>>>
>>> For what it's worth this also happens with the command line utility,
>>> it's just not as obvious. Without -multi, it only prints the "0" for the
>>> progress before the error halts execution:
>>> gdalwarp /vsis3/your-bucket/test/input.vrt output.tif
>>> Processing /vsis3/your-bucket/test/input.vrt [1/1] : 0ERROR 4:
>>> `/vsis3/your-bucket/test/input2.tif' does not exist in the file system, and
>>> is not recognized as a supported dataset name.
>>>
>>> But with -multi, notice the progress goes to 100%:
>>> gdalwarp /vsis3/your-bucket/test/input.vrt output.tif -multi
>>> Processing /vsis3/your-bucket/test/input.vrt [1/1] : 0ERROR 4:
>>> `/vsis3/your-bucket/test/input2.tif' does not exist in the file system, and
>>> is not recognized as a supported dataset name.
>>> ...10...20...30...40...50...60...70...80...90...100 - done.
>>>
>>> I guess my workaround is to just not use multithread=True. But is this
>>> something that could be fixed?
>>>
>>> Thanks
>>> _______________________________________________
>>> gdal-dev mailing list
>>> gdal-dev@lists.osgeo.org
>>> https://lists.osgeo.org/mailman/listinfo/gdal-dev
>>>
>> _______________________________________________
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>
--
Sean Gillies
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