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Aggregates have internal state that is maintained by Concordance automatically. An aggregate validates incoming commands and emits one or more events in response to each command. Aggregate state can be mutated through the application of events.

Concordance aggregates, like all other event sourcing primitives, are just specialized wasmCloud actors.

An a forthcoming release, the developer experience will be much improved with automatic code generation. For now, if you want to experiment with Concordance and aggregates, all you need to do is build a wasmCloud actor that adheres to the interface found in the GitHub repository.

For an example of how to set up the Cargo.toml file and code generation, see the bank account aggregate example.