Has anyone here ever made a Subscription work on iOS under K

Question

Has anyone here ever made a Subscription work on iOS under Kotlin Native willing to share an example of how they are doing it I ve time boxed myself to figure this out this morning and I ve failed So hoping someone else has done this Thanks in advance

mbonnin · Answer

That might not exactly be what you re looking since it s for MacOS and based on `dev 3 x` but I just added a subscription test that makes K N subscriptions against the

Neal Sanche · Answer

The `runWithMainLoop` sections in the tests are likely why they work I m going to work on a super small sample that shows the problems that I m having with this I either get illegal dereference or the frozen access exceptions and I have no idea why this would be happening when the non subscription mutations and queries code works fine I m definitely missing something

mbonnin · Answer

Oh yea everything in the iOS code assumes coroutines run from the main loop

mbonnin · Answer

If you re running `coroutines mt` that might the issue

mbonnin · Answer

There s some details there <https github com apollographql apollo android issues 2916>

Neal Sanche · Answer

Definitely running `coroutines mt` but it works for queries and mutations The difference I guess is the web socket setup

Neal Sanche · Answer

The link you shared above is pretty much exactly what I m running into but not experienced enough to know how to solve yet slightly smiling face

mbonnin · Answer

What I don t 100 understand yet is why you would need to reference `ApolloWebSocketNetworkTransport` from something else than the main thread

Neal Sanche · Answer

So the current error I have is this ```Exception doesn t match Throws specified class list and thus isn t propagated from Kotlin to Objective C Swift as NSError It is considered unexpected and unhandled instead Program will be terminated Uncaught Kotlin exception kotlin native concurrent FreezingException freezing of Ok result= lt no name provided gt 1 23ff648 has failed first blocker is com apollographql apollo network ws ApolloWebSocketNetworkTransport b4288```

Neal Sanche · Answer

And I know not really informative The setup for this is pretty detailed I ll throw my relevant code bits here

mbonnin · Answer

Nice that d be super helpful pray

Neal Sanche · Answer

This is the poor mans DI Really the main thread of the iOS app sets the token provider which also creates the graphql client This is my attempt at trying to make the objects on one thread but it still doesn t work

Neal Sanche · Answer

This is the code that gets called to perform the subscription Here the apollo client is obtained from the graph and doesn t appear to be frozen yet But it gets frozen at some point in here Not sure why

mbonnin · Answer

You don t seem to be creating any threads there

mbonnin · Answer

In theory you don t need an `IsolateState` for `providedValues` as all this code should run from the main thread

mbonnin · Answer

Can you try using the same `MainLoopDispatcher` as from the samples <https github com apollographql apollo android blob b4b7c9a0816c7e6491d026ed216cbc215750daa8 samples multiplatform kmp lib sample src iosMain kotlin com apollographql apollo kmpsample data MainLoopDispatcher kt L17|https github com apollographql apollo android blob b4b7c9a0816c7e6491d026ed216cb n com apollographql apollo kmpsample data MainLoopDispatcher kt>

Neal Sanche · Answer

Okay will give that a try

mbonnin · Answer

What are you using at the moment out of curiosity

mbonnin · Answer

does `coroutines mt` provide `Dispatchers Main`

Neal Sanche · Answer

Yes I am using `coroutines mt` and `flowOn Dispatchers Main ` I seem to be able to make a flow in place and those elements get delivered to iOS as expected but as soon as I replace the flow with an Apollo subscription I get the frozen errors

Neal Sanche · Answer

I looked at MainLoopDispatcher which is implemented in iOSMain So guessing I d have to have an expect API that would return that so that commonMain code can use it

mbonnin · Answer

Yea most likely you can have `actual val myMainDispatcher = MainLoopDispatcher` on iOS and use Dispatchers Main on Android

Neal Sanche · Answer

Yeah Working through that The `invokeOnTimeout` has a different method signature now Using 1 4 3 mt

mbonnin · Answer

That s interesting

mbonnin · Answer

I wonder what s different I would expect the coroutines mt dispatcher to be relatively identical thinking face

mbonnin · Answer

checking out the coroutines repo

mbonnin · Answer

mbonnin · Answer

Looks like the main difference is that the coroutines mt dispatcher supports `immediate` mode

mbonnin · Answer

Besides that it s all ``` dispatch async dispatch get main queue block run ```

Neal Sanche · Answer

Okay about ready to test this had to propagate ` InternalCoroutinesApi` all over the place to get it compiling

mbonnin · Answer

Arg rereading your last sentence I thought it was working man facepalming

mbonnin · Answer

Ok so I expect this to fail in the same way given how similar the two dispatchers are

Neal Sanche · Answer

Yes it does Exactly the same error I m going to lift the apollo client creation back out of the IsolateState and see what that does

mbonnin · Answer

I would remove the IsolateState completely I don t think you need it

mbonnin · Answer

All your DI runs from the main thread

mbonnin · Answer

or at least this is what I understand how it should work

Neal Sanche · Answer

Yeah it really should but I needed it for the token provider which gets called during the network interception

mbonnin · Answer

The `BearerTokenInterceptor` being an `ApolloRequestInterceptor` will also get called from the main loop

Neal Sanche · Answer

Anyway removing the graphql client creation from the IsolateState doesn t make a difference It still gives me freezing errors

mbonnin · Answer

Everything is from the main loop sweat smile

mbonnin · Answer

Now the interceptors have a `suspend fun intercept` which is where you d do the async part because you don t want to block the main thread there

mbonnin · Answer

How do you refresh the token

Neal Sanche · Answer

This is done in app space Firebase ID token

mbonnin · Answer

thumbsup

Neal Sanche · Answer

Not brave enough to do firebase auth in KMP land

mbonnin · Answer

sweat smile

mbonnin · Answer

Bottom line if you re getting the token from the main thread as well you should be able to remove the `IsolateState`

Neal Sanche · Answer

Fair enough For whatever reason it was also frozen Graph is a kotlin object so maybe it s just freezing everything it touches

mbonnin · Answer

mbonnin · Answer

```singleton objects unless marked with kotlin native ThreadLocal are frozen and shared lazy values allowed unless cyclic frozen structures were attempted to be created```

mbonnin · Answer

What bugs me a bit is this ``` providedValues access it put TOKEN PROVIDER provider it put APOLLO CLIENT makeApolloClient ``` IIRC `IsolateState` will run the `access ` block in its own isolated worker

mbonnin · Answer

Which means the `ApolloClient` is created from a background thread

Neal Sanche · Answer

Yes I have removed that now The apolloClient is now made in a lazy block

mbonnin · Answer

There s a chance that ``` val apolloClient ApolloClient get = providedValues access it APOLLO CLIENT as ApolloClient ``` freezes the client

Neal Sanche · Answer

Updated

mbonnin · Answer

drum with drumsticks

mbonnin · Answer

Is it any better

Neal Sanche · Answer

No

mbonnin · Answer

disappointed

Neal Sanche · Answer

Honestly at this point I wonder if some sort of video call would be something you d entertain Otherwise I ll work on this some other time

mbonnin · Answer

I m happy to say hello but I m most likely going to say the same things as here slightly smiling face

mbonnin · Answer

Also it s super late here and I should probably stop working

Neal Sanche · Answer

Yeah no worries I ll let you know how I fare Going to try a few more things It s only lunch time here