IIRC Jython returns the last thing evaluated, so you shouldn't need a "return" statement? Also the ExecuteScript processor does not (currently) use any return value from a script so you should just be able to let the script finish, and ensure any "return" statements are in function declarations, not the top-level script. ... View more

If your custom code can send flow files with attributes containing the source and destination information, you can use FetchS3Object to get the file from S3, then PutFile to put it in a local file share. If your custom code does not use the NiFi API, then consider ExecuteScript with Groovy (specifying your JARs in the Module Directory property) and calling the code from there, or perhaps even ExecuteStreamCommand if you want to (or must) call it from the command line. For the former option, I discuss how to use modules in code in part 3 of my ExecuteScript Cookbook series (and the other parts have related examples). ... View more

Do you mean you tried ListSFTP to get the listings? ... View more

You're probably better served with MergeRecord, that will output the merged JSON records as an array ... View more

MonitorActivity is kind of an "inverse" processor, it does work when nothing's happened. So in your case, MonitorActivity downstream from QueryES would actually generate a flow file when none has been generated from QueryES. This in a sense emulates the behavior of NIFI-3576, by emitting a flow file where there are no query results (after X time has passed, not after the query is complete). Your original question was about empty results, I don't think this would apply when you get Y results but expect Z. ... View more

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

Yeah that's true, I misread the first sentence of your question and was thinking conversion to JSON only, my bad ... View more