How to upload current date/time into App Engine with Bulkloader tool?

How can I add a last modified time property to my entity kind that gets updated during a bulk upload?

I'm currently using appcfg upload_data to upload a csv up to my high replication datastore. I plan to have this as a cron job to do a one-way sync from our internal database to datastore. In order to account for stale records, I'd like to have it update a last modified time property and then do a map reduce to delete old records (older than a week). Records will be updated using key property.

What would be the best way to create the last modified time considering I want to reserver the ability to use the Datastore Admin to delete the entire entity kind if I need to?

Create a object model to "initialize" the datastore entity with all the necessary fields?
Add a property to my bulkuploader.yaml for the modified time and use a import transform to get the date?
Other...

Thanks in advance!

Solution

I would do this:

Add a property to my bulkuploader.yaml for the modified time and use a import transform to get the date?