How can I expand a variable within a COPY command in the Dockerfile?

[joshuabadgermyriad]

@avbentem

(Especially as, if the above code is used , the actual error message is raised because the lower-cased value does match the above, whereas the original value does not. Hence some uppercase is present in whatever value is validated.)

I can verify that it does not have anything uppercase in it, though for proprietary info purposes I cannot put the relevant URL there.