Commands and Queries

Commands are always executed as part of the main loop. They’re executed by a Processor provided by the CommandExecutorModule in the pre_process stage with priority 0.

Commands have to be reversible.

A command can have a result and if required a state which is made accessible for the revert operation. Commands are also supposed to be serializable as they might be transmitted over the network to the main instance in the session.

Commands have to be registered in crates/runtime/commander/executor/commands.rs as the command_impl! macro will generate an object safe version of every command so they can be stored and reverted.

Queries can be run outside the main loop if all dependencies are available outside as well. By default, they will run as part of the main loop as well.

Queries should never modify any state but only return data. The query as well as the data a query returns should be serializable as both might be transmitted over the network.