Deadlock when using subscriptions with two Ktor worker threads

[micke-humla]

Deadlock when using subscriptions with two Ktor worker threads

[dariuszkuc]

Thanks for the reply! Looks promising but unfortunately I find no way to override KtorGraphQLServer (without also creating my custom com.expediagroup.graphql.server.ktor.GraphQL class with all it's logic) so I can't verify if it solves the issue.

Good callout. I'll open up a separate issue to allow folks specifying their own GraphQL server impls.

[dariuszkuc]

Hello 👋
I'm guessing the underlying issue is probably the same as with the #1898. If you change GraphQLServer to switch threads for processing requests then it should work even if your Ktor engine starts with just 2 worker threads.

class MyKtorGraphQLServer(
    requestParser: KtorGraphQLRequestParser,
    contextFactory: KtorGraphQLContextFactory,
    requestHandler: GraphQLRequestHandler
) : KtorGraphQLServer(requestParser, contextFactory, requestHandler) {
    override suspend fun execute(request: ServerRequest): GraphQLServerResponse? = withContext(Dispatchers.Default) {
        super.execute(request)
    }
}

[micke-humla]

Thanks for the reply! Looks promising but unfortunately I find no way to override KtorGraphQLServer (without also creating my custom com.expediagroup.graphql.server.ktor.GraphQL class with all it's logic) so I can't verify if it solves the issue.

Also, would that really solve the problem for subscriptions which is using KtorGraphQLWebSocketServer (which is also not possible to override)?

[dariuszkuc]

Opened up #1902