feature request: workflow variable usage

as you haven’t heard from me in a while it means that I am happily using KNIME without major problems…

until now…

Well it is not that grave, but it would be nice to be more flexible with the workflow variables…

Here is my problem:
I want to reuse my workflow for different input data. And, I am writing out a lot of files as results. So in order to not overwrite the files I have to change the file names each time. This is not very convenient. I put the workflow into batch script and there I can simulate the desired behavior. However, it would be nice to be able to define a workflow variable and then e.g. in the Table writer at filename use something like:
/Path to somewhere/$My WorkflowVariable$_output1 much like the variables are used in the Java Snippet node…

Please let me know if the explanation is not clear enough or there is a solution.
Maybe you could even comment on when this could be implemented…

Thanks a lot,


So you want to compose the name of the actual output file in the text box, right? Ok, yes. Not possible. Not yet. Currently you’ll need to compose a new variable beforehand (using a sequence of variable extract - variable to table row - java snippet - row to variable - inject variables; you find an example in the workshop materials). We know it’s complicated and we will simplify this – our current plan is to have a new view to each node that shows the most prominent options in a key-value table, where the values can be edited directly (also including variables). This view is visible as soon as you select a node (no need to open the dialog). Not sure when this will happen, but that’s what we plan for.

And, btw., we take it as a compliment if you consider this a “major problem”.


I am not sure what the status of this is but I just wanted to add my vote for this feature :)

My usecase is that I have a central directory where all nodes should write their data to.  I have this directory stored in a workflow variable and I can use it in my custom nodes.  However, I would also like to be able to use it in, for example, the CSV writer node to specify the output filename (e.g., as: $workflow_var$/myfile.csv).

Since If I have to change the output directory now, I have to modify it in multiple nodes instead of just changing it in the workflow var.

Otherwise, great software, I enjoy using it!