MongoDB Storage Capabilities

[Yohan460]

Enabling mongoDB storage support and integrating it into the cli startup capabilities

Note: The feature TODOs are not mission critical to the daily operation

Happy to support as necessary going forward 😀

[jessepeterson]

I haven't had a chance to review this yet, not sure when I'll get time. But one thing I saw just glancing at the PR was that in a few places you're using "UDID" as a key or column name or something. I'd recommend against that and just using "id" or "enrollment_id" instead as NanoMDM explicitly "collapses" things like UDID (and more complex scenarios) into just "id." I do see you're using r.ID in places which is good, so this is just a "column" naming thing (does MongoDB use "columns" even? lol). Anyway, there's that until I get some more time. :)

[Yohan460]

Hey @jessepeterson, The udid field in Mongo is used as a storage for the nanomdm ID field. Essentially it works as a rename. The reason I'm doing this is becuase the internal immutable document ID is stored under the _id field and I don't really like having id and _id being so similar. Hence the rename to udid.

I did read over the ID Normalization and that's handled in this situation.

As for your comment about columns. Mongo uses a document based implementation where essentially you can dump any data you want into a database collection as long as it satisfies the defined indexes of the collection

Here is an example

nanomdm/storage/mongodb/mongodb.go

Lines 51 to 56 in 96e93e5

	_, err = storage.CheckinCollection.Indexes().CreateOne(context.TODO(), mongo.IndexModel{
	Keys: bson.M{
	"udid": 1,
	},
	Options: options.Index().SetUnique(true),
	})

This entails that the CheckIn Collection must have unique MDM Request IDs. Since the r.ID is assigned to the udid field

nanomdm/storage/mongodb/checkinStore.go

Line 36 in 96e93e5

UDID: r.ID,

FWIW I'm happy to take on any bugs this causes in the event you want to defer the whole thing to us