I have a use case to append text at the end of each line from a new file or new table. ReplaceText processor helps me in appending fixed text in each line of flowfile content but the text should be appended from second file. I cannot use MergeContent processor I do not need a union merge but as below explained -
First File : employeeID, employeeName, employeeSalary
1, John, $100
2, Kevin, $150
3, Steve, $200
Second File : employeeID, department, location.
1, Finance, CA
2, Technology, NY
3, Teaching, VA
Output : employeeID, employeeName, employeeSalary,department, location.
1, John, $100,Finance, CA
2, Kevin, $150,Technology, NY
3, Steve, $200,Teaching, VA
If your second file is a single file with a static location, you could set up a flow that just gets that file (ListFile -> FetchFile) and stores the values (with employee ID as a key and the rest as value) into a DistributedMapCache. Run that flow first before starting the second flow, which could send your "First File" above into a Split Text (to process each line) then a FetchDistributedMapCache, which will populate values from the lookup table as attributes, then a ReplaceText to get the attribute values appended to the line, then a MergeContent to put it all back together.
Alternatively if you're comfortable with a scripting language you can use ExecuteScript or InvokeScriptedProcessor. The approach might be similar to this post.