Automated clearing /tmp using QGIS batch processing?

Question

I'm currently batch processing a bunch (~200 x 200MB) of ascii grid surfaces using some SAGA and GDAL algorithms in QGIS and have been running into "out of storage" errors. The issue is that between runs of the model, the /tmp folder fills up after 7-8 surfaces are processed. Performing an "rm -r /tmp/*" between runs clears up space to restart the model. The /tmp folder isn't abnormally small (4g).

I'm not sure how unorthodox it would be to have QGIS send a command between runs to clear the /tmp folder but I'm curious to know how this could be automated (perhaps in python?) to run at the end of a model run. Any other solutions for processing lots of grids would be welcome

Answer 1

You could create a custom script in your model to clear the '/tmp' folder at the end of each run. There's numerous ways to delete files but I like to use shutil.rmtree which deletes all files/folders in a specified directory.

To do this, go to Processing Toolbox > Scripts > Tools > Create new script and copy the following (adjust the path):

import shutil

shutil.rmtree('/tmp')

Save the script into C:/Users/You/.qgis2/processing/scripts (again, adjust path as I use Windows). Then add the custom script from the list of algorithms to your model. To add it at the end of the model, check the image:

Now when you run your model in a batch process, it should clear the '/tmp' folder after each run.