Ancestry.ca shows 259.718 entries in a collection Canada, WWI CEF Personnel Files, 1914-1918 marked as NEW. It was added on 3 November. This CEF collection, exceptionally, has no pop-up giving brief details including date added and updated so I'm guessing the date from those of the previous and subsequent databases.
Here's what Ancestry provides on the collection:
This database consists of service files for men who enlisted in the Canadian Expeditionary Force (CEF) of the First World War. The database currently contains records for surnames beginning with A through G, and for most surnames beginning with H. As more service files are digitized and indexed, additional records will be added to this database.
Details available in a service file vary depending on the soldier, but typically include:
Name of enlisteeAddressBirthplaceBirth dateAgeName of next of kinRelationship to next of kinRegimental numberAdditional information about the enlistee, such as their occupation, marital status, religion, and/or physical description is often included as well.
That same page gives a link to Ancestry.com's Fold3 military database where, for an additional subscription, you can read the whole service file as digitized by Library and Archives Canada.
Naturally Ancestry hopes you will purchase a subscription and don't inform you that you can view exactly the same information at the LAC site for free. See Diefenbaker's file at https://goo.gl/2Y2nXd/.
It appears the attestation paper collection I couldn't find at Ancestry others can! I'd searched the Ancestry catalogue using military and Canada as search terms. Maybe I should have taken that extra hour in bed instead of in front of the computer!