Crate cqrs_es2

cqrs-es2

A lightweight CQRS and event sourcing framework.

Usage

Documentation is available here along with an introduction to CQRS and event sourcing.

Demo applications:

• RESTful.
• gRPC.

Modules

memory_store

A simple memory store for testing purposes only

postgres_store

Postgres store

Structs

AggregateContext

Returns the aggregate and context around it that is needed when committing events in an event store implementation.

EventContext

EventContext is a data structure that encapsulates an event with along with it’s pertinent information. All of the associated data will be transported and persisted together.

QueryContext

Returns the query and context around it that is needed when committing in a query store implementation.

Repository

This is the base framework for applying commands to produce events.

TestFramework

A framework for rigorously testing the aggregate logic, one of the most important parts of any CQRS system.

UserErrorPayload

Payload for an AggregateError::UserError, somewhat modeled on the errors produced by the validator package. This payload implements Serialize with the intention of allowing the user to return this object as the response payload.

Enums

AggregateError

The base error for the framework.

Traits

IAggregate

In CQRS (and Domain Driven Design) an Aggregate is the fundamental component that encapsulates the state and application logic (aka business rules) for the application. An Aggregate is always an entity along with all objects associated with it.

IDomainCommand

A DomainCommand represents business API call.

IDomainEvent

A DomainEvent represents any business change in the state of an Aggregate. DomainEvents are immutable and with event sourcing they are the source of truth.

IEventStore

The abstract central source for loading past events and committing new events.

IQuery

A Query is a read element in a CQRS system. As events are emitted multiple downstream queries are updated to reflect the current state of the system. A query may also be referred to as a ‘view’, the concepts are identical but ‘query’ is used here to conform with CQRS nomenclature.

IQueryProcessor

Each CQRS platform should have one or more QueryProcessors where it will distribute committed events, it is the responsibility of the QueryProcessor to update any interested queries.

IQueryStore

The abstract central source for loading and committing queries.