I have problems using expression language in the FetchFTP for setting host, port and username. I have set the properties as indicated in the attachment, and confirmed in the queue feeding it, that the FlowFiles do indeed have the mentioned attributes already set to correct values (coming from a ListFTP processor upstream).
The error indicated in the other screenshot seem to tell me that empty string are being used for values - I don't knwo why. If I replace the expression language with hardcoded values, it works fine - but I'd like to not have to reenter the parameters here, when already input for ListFTP and passed along the FlowFiles as attributes.
Hope you can help. Thanks.
Can you find the corresponding error in nifi-app.log and provide the stacktrace here so we can possibly see which property is the issue?
Also, might be helpful to route the failure relationship of FetchFTP to a LogAttribute processor so that the attributes of each failed flow file will be logged to nifi-app.log and then you can double-check they had the expected attributes.
I tried routing all failure relationships from FetchFTP to a LogAttribtue processor, but flowfiles never make it so far - they get stock upstream in the queue feeding FetchFTP that fails with the NumberException and empty string (see attached ftp2.png from first entry here).
I have double checked the flowfiles into FetchFTP and they do contain the attributes refered to in expression language for FetchFTP. Also tried making a separate test setup with GenerateFlowfile and having UpdateAttribute manually set attributes for use in a test FetchFTP - same problem.
Not sure how I get the stacktrace to appear in nifi-app.log.