A pipeline with a GroupBy transform fails with the following error when called as part of a workflow running in a remote hop server:
My guess it's a serialization error because the aggregation type attribute of the GroupBy action is set to '-' in the .zip that is sent to the remote hop server.
Find attached a reproducer. The group-by-agg-fail.tar.gz contains a workflow W1, a pipeline P1 and an input file bod.csv.
The script reproducer.sh list the necessary steps. It depends on environment variable HOP_CLIENT_INSTALL_DIR pointing to a Hop installation folder.
As I commented in the users@ ML, the error is triggered by running the workflow remotely. In any other configuration (workflow locally, pipeline locally, pipeline remote) everything runs smoothly.