Knime execution from Python logs

I’m using the library from PyPi to integrate my workflows in my scripts.
Where can I find the logs that are usually generated during the execution? As far as I could see it was not appended in the usual KNIME_WORSPACE.metadata\knime.log

The problem is that the library uses the option -data in the call of knime.exe, therefore the logs end up in this folder which by default is a temporary folder.

The use of this option was also removes the preferences (R snippets where not able to find the R Home), specifying -preferences in the call doesn’t seem to solve the issue

In the knimepy project’s github repo, PR#19 ( introduces a change to not specify -data when specifying save_after_execution=True. This was motivated by my feeling frustrated that the logs were not accessible to me after a failed execution. Since I use save_after_execution=True to help me debug things any time a workflow fails, I thought this change would make sense as well as be helpful when/where I needed it most.

I have not invoked a workflow from knimepy that contained R snippet nodes – that is an interesting problem. When you wrote, “specifying -preferences in the call doesn’t seem to solve the issue”, does that mean you tried modifying knimepy to add -preferences ... to its execution string for KNIME?

Yes I tried to modify knimepy to add the preference option but if I have both -data and -preference the workflow doesn’t even start (error code 2). I’ve replicated the same issues by starting the workflow from command line.
I’ve solved the R home issue by commenting the row with the -data option (my current workflows don’t use it anyway) but it’s not a nice solution.

I’ve implemented a solution that automatically locate the logs in the temporary folder and save them in a customizable folder but there I get stuck due to the missing preferences

Would you be willing to try using the from PR#19 (direct link to that updated file: to see if you like the control it offers for preservation of the logs?

It does not properly address the issue with the R Snippet nodes. While it will suppress the use of -data, and this probably means the R Snippet nodes will work happily for you, I do not regard this as the right solution – at least I would not want to feel obligated to always save the workflow state after execution. But I do like the idea of saving workflow state when I want to debug and review the logs afterwards.

If you like the updated in PR#19, then I want to get that into a new release. Then we still also need to sort out the undesirable behavior with the R Snippet nodes.

I will try it next week and let you know.

FYI in my version of the library I also modified the LocalWorkflow class to include an “executed” attribute (boolean) and to save the the last return code from the subprocess command, if interested I will open a feature request in git or share my version of the code

Yes please – I would love to see those modifications. Exposing the last return code does sound useful. The “executed” attribute makes me think about what to do in the RemoteWorkflow class.

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