Plugin Workers

Plugin workers are a way to get around the fact that wasm/wasi threads are not stable yet. If a plugin has a potentially long operation to perform, it can declare a worker on startup and send and receive messages from it.

The ZellijWorker trait

zellij-tile provides the following interface for workers:

pub trait ZellijWorker<'de>: Default + Serialize + Deserialize<'de> {
    fn on_message(&mut self, message: String, payload: String) {}
}

The on_message method will be called when the plugin uses the post_message_to plugin command with an arbitrary message and payload. These are specified as Strings so that plugins can decide on their own method of serialization.

Registering Workers

To register workers on startup, plugins can use the register_worker macro like so:

pub struct TestWorker {
    // ...
}
impl ZellijWorker for TestWorker {
    // ...
}
register_worker!(
    TestWorker,
    test_worker, // the namespace of the worker, anything before the final _worker will be the worker namespace
    TEST_WORKER // a name for static variable used to store the worker state between invocations
);

For more information, please see the zellij-tile API documentation.

Sending messages to workers

When a plugin (or another worker) wishes to send messages to a worker, they use the post_message_to plugin command. They should use the worker namespace used when registering the worker, eg. post_message_to("test", ...) for the test_worker example above.

Sending messages from workers to plugins

When a worker wishes to send a message to a plugin, they use the post_message_to_plugin command. This message will trigger the plugin's update method with a CustomMessage event. Be sure to subscribe to it beforehand!