<div dir="ltr"><div>Hi Tim,</div><div><br></div><div>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.</div><div><br></div><div>Hope this helps,<br></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Sat, Mar 1, 2025 at 11:30 AM Tim Harris via gdal-dev <<a href="mailto:gdal-dev@lists.osgeo.org">gdal-dev@lists.osgeo.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>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.</div><div><br></div><div>So create two TIFs and a VRT, then remove one TIF:</div><div><span style="font-family:monospace">gdal_create -of GTiff -outsize 1000 1000 -bands 1 -a_srs EPSG:4326 -a_ullr 0 1 1 0 input1.tif<br>gdal_create -of GTiff -outsize 1000 1000 -bands 1 -a_srs EPSG:4326 -a_ullr 1 1 2 0 input2.tif<br>gdalbuildvrt input.vrt input1.tif input2.tif<br>rm input2.tif</span></div><div><br></div><div>Then in Python:</div><div><span style="font-family:monospace">from osgeo import gdal</span></div><div><span style="font-family:monospace">gdal.UseExceptions()</span></div><div><br></div><div>This raises an exception</div><div><span style="font-family:monospace">gdal.Warp("output.tif", "input.vrt", callback=gdal.TermProgress)</span></div><div><br></div><div></div><div>But this does not:</div><div><span style="font-family:monospace">gdal.Warp("output.tif", "input.vrt", callback=gdal.TermProgress, multithread=True)</span></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Mar 1, 2025 at 7:58 AM Javier Jimenez Shaw <<a href="mailto:j1@jimenezshaw.com" target="_blank">j1@jimenezshaw.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto">Does it also happen without S3, just with local files?<div dir="auto">It would simplify the analysis </div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, 1 Mar 2025, 01:01 Tim Harris via gdal-dev, <<a href="mailto:gdal-dev@lists.osgeo.org" target="_blank">gdal-dev@lists.osgeo.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>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.</div><div><br></div><div>I saw there's this pretty old GitHub issue that may be related, but I'm not sure:</div><div><a href="https://github.com/OSGeo/gdal/issues/3372" rel="noreferrer" target="_blank">https://github.com/OSGeo/gdal/issues/3372</a></div><div><br></div><div>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:</div><div><a href="https://github.com/OSGeo/gdal/issues/11552" rel="noreferrer" target="_blank">https://github.com/OSGeo/gdal/issues/11552</a></div><div><br></div><div>Here's a section of my log file (filename sanitized):</div><div><span style="font-family:monospace">ERROR 11: CURL error: Empty reply from server<br> 0...10...20...30...40...50...60...70...80...90...100 - done.<br> ERROR 4: `/vsis3/path/to/raster.tif' does not exist in the file system, and is not recognized as a supported dataset name.</span><br> </div><div><br></div><div>Notice the CURL error but the progress still goes to 100%. The warp completed successfully despite the read error.</div><div><br></div><div>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:</div><div><span style="font-family:monospace">gdal_create -of GTiff -outsize 1000 1000 -bands 1 -a_srs EPSG:4326 -a_ullr 0 1 1 0 input1.tif<br>gdal_create -of GTiff -outsize 1000 1000 -bands 1 -a_srs EPSG:4326 -a_ullr 1 1 2 0 input2.tif<br>aws s3 cp input1.tif s3://your-bucket/test/input1.tif<br>aws s3 cp input2.tif s3://your-bucket/test/input2.tif<br>gdalbuildvrt input.vrt /vsis3/your-bucket/test/input1.tif /vsis3/your-bucket/test/input2.tif<br>aws s3 cp input.vrt s3://your-bucket/test/input.vrt<br>aws s3 rm s3://your-bucket/test/input2.tif</span></div><div><br></div><div>Then in Python:</div><div><span style="font-family:monospace">from osgeo import gdal<br>gdal.UseExceptions()<br>gdal.Warp("output.tif", "/vsis3/tharris-bucket/test/input.vrt", callback=gdal.TermProgress)</span></div><div><br></div><div>This throws a RuntimeError, as expected. But delete the partial file and try with multithread=True:</div><div><span style="font-family:monospace">rm output.tif</span></div><div><span style="font-family:monospace">gdal.Warp("output.tif", "/vsis3/tharris-bucket/test/input.vrt", callback=gdal.TermProgress, multithread=True)</span></div><div><br></div><div>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.</div><div><br></div><div>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:</div><div><span style="font-family:monospace">gdalwarp /vsis3/your-bucket/test/input.vrt output.tif<br>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.</span></div><div><br></div><div>But with -multi, notice the progress goes to 100%:</div><div><span style="font-family:monospace">gdalwarp /vsis3/your-bucket/test/input.vrt output.tif -multi<br>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.<br>...10...20...30...40...50...60...70...80...90...100 - done.</span></div><div><br></div><div>I guess my workaround is to just not use multithread=True. But is this something that could be fixed?</div><div><br></div><div>Thanks</div></div>
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