Datastream Extract: define custom extract file name

• By default, the filename of each Data Extract is {datastreamtype}-{datastream-id}-{uuid}. For example, adwords-230-20171208-dbd25e9a223b48ac87649965a81966af.csv.
• Use the transformation set_meta with fieldname datastream_extract_filename to change the {uuid} part of the Data Extract's filename. You cannot change the {datastreamtype}-{datastream-id} part of the filename this way.
• You can use either a dynamic value based on another column (screenshot 1) or a static value (screenshot 2) as visualized in the two examples below:

As a result of the second transformation, the Data Extract's filename changes to adwords-230-20171208-google-adwords.csv.