GET Resource and Variable Condition Loop End

KNIME Analytics Platform
#1

Hey folks,

currently I am working a lot with the REST nodes. I am using the GET Resource node which sometimes fails, emitting a "502 Bad Gateway" response status.

My idea was to enclose the GET Resource node with a Generic Loop Start and a Variable Condition Loop End node to re-submit my request, which unfortunately only works in theory.

The reason this does not work is, that the Variable Condition Loop End node emits a "DataSpec generated by configure does not match spec after execution." error. Even though the Collect rows from last iteration only option is enabled. Please notice the screenshot attached to my post to see what I mean.

How can I solve this problem?

What is the best way to enclose my GET Resource node and repeat the execution until the Status Code is "200 OK"?

Why is the Variable Condition Loop End node paying so much attention to the Bad Gateway HTML content when it shouldn't do anything except collecting rows from the last (!) iteration, which means the condition on the correspondent flow variable is met?

Best,
Marc

#2

Hi Marc,

You might try the recursive loops for this purpose. In case you know the expected table structure, you can use that information to create an empty table with the IF (switch) nodes for the failing case.

Hope this helps, gabor