ExecuteScript makes two relationships available, REL_SUCCESS and REL_FAILURE, you can use session.transfer(flowFile, relationship) to do the routing. Check my ExecuteScript Cookbook series (part 1) for examples on how to transfer a flow file. Once you have a boolean or other determining factor on where to route it, you can use the example to do the transfer. If you have multiple relationships, and you can't use RouteOnAttribute due to the conditions being in the content, consider QueryRecord as you can use a SQL statement to do routing on the content. If that doesn't satisfy your use case, you can use InvokeScriptedProcessor to define relationships on the fly, based on some condition (perhaps user-defined properties like RouteOnAttribute and QueryRecord use). Consult the code for these processors for examples on how to implement this with InvokeScriptedProcessor. ... View more

You only need one session per execution of the script. Using that session, you can get, create, remove, and transfer as many flow files as you want. If you get or create a flow file from the session, then you must transfer or remove it before the end of the script, or else you will get a "Transfer relationship not specified" error. Also you can only transfer each flow file once, if you attempt to transfer the same flow file more than once, you will get the error you describe above. ... View more