Consistency in CtOkHttp4Client ExecutorService usage

[pintomau]

Hey.

We're evaluating the usage of Virtual Threads with Executors.newVirtualThreadPerTaskExecutor();.

I've noticed that there's an inconsistency in the usage of ExecutorService executor in CtOkHttp4Client:

    public CtOkHttp4Client(final ExecutorService executor) {
        super(executor);
        okHttpClient = clientBuilder.get().dispatcher(createDispatcher(executor, MAX_REQUESTS, MAX_REQUESTS)).build();
    }

    public CtOkHttp4Client(final ExecutorService executor, final BuilderOptions options) {
        super(executor);
        okHttpClient = options.plus(clientBuilder.get().dispatcher(createDispatcher(MAX_REQUESTS, MAX_REQUESTS)))
                .build();
    }

    public CtOkHttp4Client(final ExecutorService executor, final int maxRequests, final int maxRequestsPerHost) {
        super(executor);
        okHttpClient = clientBuilder.get()
                .dispatcher(createDispatcher(executor, maxRequests, maxRequestsPerHost))
                .build();
    }

    public CtOkHttp4Client(final ExecutorService executor, final int maxRequests, final int maxRequestsPerHost,
            final BuilderOptions options) {
        super(executor);
        okHttpClient = options
                .plus(clientBuilder.get().dispatcher(createDispatcher(executor, maxRequests, maxRequestsPerHost)))
                .build();
    }

The second constructor doesn't reuse the passed executorService when creating the dispatcher, while all others that get the same argument do.

It just so happens that this one would be the ideal one for us 🤠.

Is there a reason for this, or is it an oversight?

Besides this, any thoughts or recommendations on using the Virtual Threads executor with the SDK? Maybe you've already done experimenting on your end? Is the SDK prone to Thread Pinning?

Thanks.

[jenschude]

We didn't experiment yet with virtual threads.

When I remember it right the executor wasn't forwarded to the OkHttp dispatcher for backwards compatibility reasons as it potentially would have changed the behavior.

In case you want to forward the executor to OkHttp use one of the methods with the maxRequest arguments or rebuild the functionality

ExecutorService executor = ForkJoinPool.commonPool();
final okhttp3.Dispatcher dispatcher = new okhttp3.Dispatcher(executor);
dispatcher.setMaxRequests(CtOkHttp4Client.MAX_REQUESTS);
dispatcher.setMaxRequestsPerHost(CtOkHttp4Client.MAX_REQUESTS);

new CtOkHttp4Client(executor, builder -> builder.dispatcher(dispatcher));

Besides you should load test any changes to the default executor as OkHttp by default instantiates an unbound ThreadPool executor with a SynchronousQueue.