[−][src]Crate cqrs_es

cqrs

A lightweight, opinionated CQRS and event sourcing framework targeting serverless architectures.

cqrs-es is available from Crates.io or Github.

[dependencies]
cqrs-es = "0.0.18"

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

A demo application is available here.

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.
Support for snapshots.

mem_store	An in-memory event store suitable for local testing.
test	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).

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

The base error for the framework.

Aggregate	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.
Command	A `Command` represents a request to modify the state of an `Aggregate` by producing `DomainEvent`s.
DomainEvent	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.
EventStore	The abstract central source for loading past events and committing new events.
Query	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.
QueryProcessor	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.