Attribute Macro rpc 

#[rpc]

Marks an async method as an RPC handler (read-only operations).

Use #[rpc] for methods that do not modify state. These are simple request/response handlers for queries and reads.

For methods that modify state, use #[workflow] instead.

Usage

#[entity_impl]
#[state(MyState)]
impl MyEntity {
    #[rpc]
    async fn get_count(&self) -> Result<i32, ClusterError> {
        Ok(self.state().count)  // Read-only access
    }

    #[rpc]
    async fn get_status(&self) -> Result<Status, ClusterError> {
        Ok(self.state().status.clone())
    }
}

Visibility

By default, #[rpc] methods are #[public] (externally callable). Combine with #[protected] or #[private] to restrict access.

When to Use

• Use #[rpc] for read-only queries that don’t modify state
• Use #[workflow] for any operation that calls state_mut()

Generated Code

For each #[rpc] method, the macro generates:

• A dispatch arm in handle_request for the method tag
• A typed client method with the same signature