Cannot append to a file in KNIME Server

KNIME Server
1

Hi,
I’m trying to append rows to a file, using a workflow relative URL in CSV Writer with the “Append”
option in Writer Options.
It works well in KNIME Analytics Platform, but when I deploy the workflow to KNIME Server and execute, I get the following message:
CSV Writer 0:102 - ERROR: Execute failed: knime://knime.workflow/…/Logs/Log_2020-04-27.txt points to a remote file but append to remote files is not possible!
It doesn’t matter if the file already exists or is a new one.

How can I append to a csv (or text) file in KNIME Server?
Why does KNIME Server relate to this URL as a remote file?

Thanks,
Dror

2

Hello Dror,
This is happening due to the fact that the executor accesses the KNIME Server via HTTP, which does not allow appending. This is done as an abstraction of the server’s file system and is especially useful in scenarios with distributed executors, where the workflow may not even run on the same machine as the server with its workflow repository and therefore has no direct file system access. I recommend you read in the whole file, append your rows using Concatenate and then write it back using the CSV Writer.
Kind regards,
Alexander

1 Like
3

Hi @AlexanderFillbrunn,
thanks a lot!
Dror