While learning Codex, I asked it if it could modernize my existing CloudKit library by wrapping CKSyncEngine (iOS 17+) to add .public database support.

After explaining why CKSyncEngine likely does not support .public—mainly an inability to provide at scale the same API .private/.shared affords—Codex said yes, with a few caveats.

Then I thought of something more interesting to ask, and came away impressed. #cloudkit

I’m working on a #SwiftUI “admin” utility macOS app that’s pretty information dense and probably should be very hierarchical (for editing #CloudKit entities).

Is this navigationSplitView navigation structure too wild (possible)?

It’s kind of a 3 + 1 column Split View, but the 4th “column” is just an (optional) inspector view on the detail view. The content column would be a small table of entities (instead of a list view like most apps).

📣 Speaker Announcement

From building indie apps like Tasks & Karo, we're thrilled to welcome @mufasayc 🎉

Mustafa will take us from zero to sync with CloudKit — covering containers, databases, and real-world lessons learned ☁️

Expect practical tips, honest insights, and a lot of laughs along the way 😄

#DeepDishSwift #iOS #Swift #CloudKit #IndieApps

#iosdev #buildInPublic #coredata #swiftTesting

Will be exploring Apple’s cktool for #cloudkit setup, which hopefully will let me populate data that will let me test sync

https://developer.apple.com/icloud/ck-tool/

27/n

Wondering if you can share your data with SQLiteData from @pointfreeco Well wonder no more. It just works!!!!!
Fantastic #CloudKit #Swift #SwiftUI #SQLite

#iosdev #buildInPublic #coredata #cloudKit

Roughed in a little prototype - UI mostly done, some test classes to create Tunes and TuneSets. Tomorrow rough in Collections. Nice that UIKit now lets us add UISplitViewControllers as tabs on UITabControllers.

15/n

#iosdev #buildInPublic #coredata #cloudKit

So the next question is - create a purpose-built prototype to experiment with attributed relationships or bang away at a disposable branch of my main project? I know what I _should_ do... And it will make things easier to share here without distractions. So a new project using Storyboard (i.e. UIKit) template with CoreData. Minimum deployment will be iOS 17. No CloudKit as yet, I want to be able to test migration from ordered many:many .

14/n

#iosdev #buildInPublic #coredata #cloudKit

Enough for tonight. Tomorrow I'll start prototyping the migration from explicitly ordered many:many to implicitly ordered via intermediate attributed relationship objects.

13/n

#iosdev #buildInPublic #coredata #cloudKit I also have make sure I'm selecting the Private database and the com.apple.coredata.cloudkit'recordName' is not marked queryable

https://lyons.app/2021/07/05/how-to-fix-field-recordname-is-not-marked-queryable-in-cloudkit/

gave me the answer: I have to modify the schema by adding a queryable index called recordName to the recordName metadata field for each record type so I can view the records. I also have make sure I'm selecting the Private database and the com.apple.coredata.cloudkit zone.
12/n
Edit: to fix link

#iosdev #buildInPublic #coredata #cloudKit

Got the demo working after some annoying debug sessions. Seems like it has not been revisited since 2022, and iOS 18 changed the behaviour of collectionView.dequeueReusableCell - as of iOS 18 it asserts if you call it outside of cellForItemAt indexpath. it was being called in awakeFromNib to set a font.

You would think that a company with the resources of Apple would at a minimum task interns to COMPILE AND RUN demos called out in the docs 11/n

#iosdev #buildInPublic #coredata #cloudKit

There is some Apple demo code from WWDC 2022 that gives an example of deduplication on CloudKit sync. It's a simplified demo but it does give an example of a many:many (unordered) relationship. Let's see if we can get it running.
https://developer.apple.com/documentation/coredata/synchronizing-a-local-store-to-the-cloud

10/n

And here is the blog post detailing the changes.

https://smork.info/blog/posts/beer-diary-version-2-4-released/

#ios #swift #swiftui #coredata #cloudkit

#indiedev #irishmusic #iosdev #buildInPublic #coredata #cloudKit

As an aside - I've learned a lot about CoreData and CloudKit from @fatbobman's blog.

https://fatbobman.com/en/posts/coredatawithcloudkit-1/

9/n

#indiedev #irishmusic #iosdev #buildInPublic #coredata #cloudKit

Apple has improved their migration support since I last looked - migrating to the data model outlined above would work as a staged migration:
- add the new entities and any attributes needed to define ordering or deduplication
- populate the intermediate attributed relationships
- delete the old entities

https://developer.apple.com/documentation/coredata/staged-migrations

Now we can safely move from NSPersistentContainer to a NSPersistentCloudKitContainer

8/n

#indiedev #irishmusic #iosdev #buildInPublic #coredata #cloudKit

Now we've sketched out a workable data model that works in both coreData and CloudKit, we need to work out:
- how to migrate from the existing model to the new one without losing data.
- how to handle merging databases from different devices given that the user might have duplicate entries or collections with different members or different ordering

7/n

#indiedev #irishmusic #iosdev #buildInPublic #coredata #cloudKit

diagrams of where we are so far…
6/n

#indiedev #irishmusic #iosdev #buildInPublic #coredata #cloudKit

The second case is a little more complex. Collections can contain Tunes and TuneSets. By default, they are time-ordered when users add to their contents. Users can also reorder them, and I've had requests (not yet implemented) for alphabetical and most-recent first ordering.
A superclass (Searchable) inherited by both TuneSet and Tune allows for containment of both in a Collection.

5/n

#indiedev #irishmusic #iosdev #buildInPublic #coredata #cloudKit

Tune to TuneSet is a many:many relationship ordered by the tunes’ play order. Functionally, the user can add Tunes to TuneSets and re-order or remove them. We must convert the many:many relationship to an intermediate object with an ordering attribute that we can use when we retrieve a TuneSet. We will have to be able to manipulate the ordering attribute to let the user drag Tunes to re-order them in the UI.
4/n

#indiedev #irishmusic #iosdev #buildInPublic #coredata

To zoom in a bit on the problem at hand: #cloudKit is the obvious choice for sync between devices. Apple's documentation would have you believe that all you need to do is change your NSPersistentContainer to a NSPersistentCloudKitContainer and all will be well!
Not so fast.
First of all, the coredata and cloudkit data models have to be compatible. In this case, we find the dreaded OrderedRelationship in two places.
3/n

It seems related to encrypted fields. I can reproduce it both with CKSyncEngine and with CKDatabase.modifyRecords(…) where isAtomic is false. Still not sure what’s going on.

Has anyone seen unexpected .batchRequestFailed partial errors on non-atomic saves? Or when using CKSyncEngine, where non-atomic is the default?

#iCloud #CloudKit #CKSyncEngine #AdvancedDataProtection #E2EE