Want to stop execution of a workflow if certain condition doesn't match

[tamzid89]

I want to compare total number of a count in a column between source and target. And if the source count is higher than the target only than I want to run the workflow. Otherwise i want to terminate the workflow execution. Not sure how to achieve that in knime.

[iCFO]

There are probably cleaner solutions, but I have used an If Switch and the Disable Flow component.

Enable-Disable Flow – takbb

[iCFO]

I just remembered that I have simplified this to just controlling the Enable / Disable Flow component with a conditional flow variable. You have to attach it to every separate branch in a workflow since it only shuts down the downstream nodes.

I also have a vague memory of modifying the component to add the flow variable toggle, but not sure… If you don’t see it then let me know and I will upload it for you.

[mlauber71]

@tamzid89 one way I would do this is use the

Empty Table Switch

or if it is indeed just the incoming data try use

Breakpoint

Also a construct with a CASE Switch Start – KNIME Community Hub could work.

Maybe you start by constructing a sample workflow that would represent your case. Would this workflow do something else besides stopping. Could a loop be involved? Are there other branches in the workflow that might need handling?

Stop my loop if the column sum is greater than 50% of my flow variable

@kowisoft it could look something like this. Collection the iterating values in a temporary file and appending that at each step of the loop. And then like you have already done collect the sum of the column and then make a decision to sop (or not). Maybe not the most elegant way… Just make sure to reset the temporary file. One could also automate that by using a switch catching the first iteration of the loop (I have and example of that somewhere). [image] [image]

More general there is the

https://docs.knime.com/latest/analytics_platform_flow_control_guide/index.html#introduction

[iCFO]

@mlauber71 Haven’t tried out Breakpoint yet…

Does it halt the execution of the entire workflow, or just downstream nodes?

[mlauber71]

@iCFO I have no in depth experience with it. In general: one will have to connect the nodes that should be stopped with Flow Variables to make sure the rest of the execution also gets stopped. So some planning might be required.

Also the question might be what kind of automation this solution should serve. Is it just one user on the local machine or is this meant to be run on a KNIME server. The solution might differ. I have used the Empty table switch: if no data is there just stop/deactivate the rest of the workflow.

stop workflow in specifc case

Hi @Mokrani - Here’s an example workflow I came up with. Basically you convert the “files” column into a workflow variable, use the Java Edit Variable (simple) node to convert that variable, and set up an If Switch node based on whether “files” is missing or not. If it is, it takes the bottom path of the If switch and fails. Otherwise, the workflow continues. IfSwitchFailInExecutionExample.knwf (15.3 KB) [2018-04-24%2010_15_24-KNIME%20Analytics%20Platform]