Crate cqrs_es[−][src]
Expand description
cqrs
A lightweight, opinionated CQRS and event sourcing framework targeting serverless architectures.
Installation
cqrs-es is available from Crates.io or Github.
[dependencies]
cqrs-es = "0.1.3"
Usage
Documentation is available here along with an introduction to CQRS and event sourcing.
A demo application is available here.
Todos
- Event upcasters.
- Event serialization uses the event type as the root node of the JSON tree. This simplifies deserialization but is non-standard.
- A persistence implementation for DynamoDb.
- A persistence implementation for MySql.
Modules
An in-memory event store suitable for local testing.
Test provides a test framework for building a resilient test base around aggregates.
A TestFramework
should be used to build a comprehensive set of aggregate tests to verify
your application logic (aka business rules).
Structs
This is the base framework for applying commands to produce events.
EventEnvelope
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.
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
The base error for the framework.
Traits
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.
Returns the aggregate and context around it that is needed when committing events
A DomainEvent
represents any business change in the state of an Aggregate
. DomainEvent
s
are immutable and with event sourcing
they are the source of truth.
The abstract central source for loading past events and committing new events.
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.
Each CQRS platform should have one or more QueryProcessor
s where it will distribute committed
events, it is the responsibility of the QueryProcessor
to update any interested
queries.