When creating a workflow to insert data into Mongo, I have many data flows running into the PutMongo processor. I would like to insert these records into collections that show their data source via an attribute. The PutMongo processor (which is driven by AbstractMongoProcessor) doesn't allow for dynamic collection assignment via expression language. The workaround is having 1..n PutMongo processors, all pointing to the same DB, with different collection names assigned for each workflow. This seems very un-Nifi, and appears to be fairly simple to modify the AbstractMongoProcessor to allow expressions.