streaming.md

Watching output as it happens

Every snippet here is executed by ExamplesTest.

A control client stays attached and pushes terminal output as tmux produces it, rather than being asked:

try (ControlClient client = ControlClient.attach(server.config(), session.id());
        EventSubscription<PaneOutput> output = client.subscribeOutput(32)) {

    client.send("send-keys", "-t", session.name(), "echo streamed", "Enter");

    PaneOutput arrived = output.next(Duration.ofSeconds(5)).orElseThrow();
    arrived.data().contains("streamed");  // → true
}

Attaching is what makes tmux push at all. A control client that never attaches sees no output, however long it waits.

Each subscriber chooses a fixed buffer capacity. A full buffer drops its oldest value, and droppedCount() reports the exact loss. The control reader only fills those buffers; caller code runs on the thread that calls next().

Requests are serialized

A control client has one reply stream, so send calls run one at a time. A timeout closes the client because the next reply can no longer be attributed safely. Use Server for ordinary commands; use ControlClient when the persistent event stream is the requirement.