Display Results/Data Quality problems/Log Data to the user


I’m struggling with a practical problem and I’m hoping someone can point me in the right direction.
I created a workflow for my colleagues to create a monthly excel report for one of our clients. This report pulls data from different sources and does a lot of things and finally presents a wonderfull excel sheet. So far so good.
Now thing can be sub-optimal concerning the actual data. There might be broken data points, which need correction in the source systems to have a valid report in the end. These issues I want to point out to the users, which don’t have a deep understanding of Knime themselves. So the workflow doesn’t and shouldn’t fail, but I want to present a message like:

This issue needs fixing: A1234, B234, C23123
Add mapping for this data: 88293-12, 2391232-12
All other data is correct

What is the proper way to do something like this?

Bonus Question:
How can I have easy customisation of the workflow, like specification of from and to dates? Forms only seem to work in conjunction with Knime-Server which is right now not an option for us. And i find it hard to develop/get started with it atm.


Hello @whizkid,

welcome to KNIME Community!

What you are looking for is logging mechanism which you need to implement. There is no proper way and it depends on your workflow design and logic. What is usually used are Try/Catch sequences and Table Validator nodes - Table Validator & Table Validator (Reference).
See this topic for example: Knime Logging Mechanism

Bonus answer:
Parameterization in KNIME is done using flow variables.
See here : https://www.youtube.com/watch?v=EvcRiQea3FA&ab_channel=KNIMETV

Have a nice day,

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Thanks @ipazin for your answers.
My issue is not to create the error messages and notifications, but I want to show them prominently in the workflow display. That’s the part I’m lacking. Maybe something like an alert message, when a certain node is executed.

Similarly the flow variables are used heavily by me at the moment, but to change them, the user needs to dig down pretty deep into the setting. Ideally I’d like to have a neat overview/form to display to the user, when he executes a certain node.

Hello @whizkid,

Ok. I see now. To my knowledge something like this could be done with Java.
See here: Possible to create a popup message

Not sure I follow regarding flow variables and going deep down? Define all variables at beginning of flow and put them into Component?


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