command

Documentation

Overview

Package command contains types and interfaces for implementing Command Handlers, necessary for producing side effects in your Aggregates and system, and implement your Domain's business logic.

Index

• type Command
• type Envelope
  • func FromGenericEnvelope[T Command](cmd GenericEnvelope) (Envelope[T], bool)
  • func ToEnvelope[T Command](cmd T) Envelope[T]
  • func (cmd Envelope[T]) ToGenericEnvelope() GenericEnvelope
• type GenericEnvelope
• type Handler
• type HandlerFunc
  • func (fn HandlerFunc[T]) Handle(ctx context.Context, cmd Envelope[T]) error

Types

type Command

type Command message.Message

Command is a specific kind of Message that represents an intent. Commands should be phrased in the present, imperative tense, such as "ActivateUser" or "CreateOrder".

type Envelope

type Envelope[T Command] message.Envelope[T]

Envelope carries both a Command and some optional Metadata attached to it.

func FromGenericEnvelope

func FromGenericEnvelope[T Command](cmd GenericEnvelope) (Envelope[T], bool)

FromGenericEnvelope attempts to type-cast a GenericEnvelope instance into a strongly-typed Command Envelope.

A boolean guard is returned to signal whether the type-casting was successful or not.

func ToEnvelope

func ToEnvelope[T Command](cmd T) Envelope[T]

ToEnvelope is a convenience function that wraps the provided Command type into an Envelope, with no metadata attached to it.

func (Envelope[T]) ToGenericEnvelope

func (cmd Envelope[T]) ToGenericEnvelope() GenericEnvelope

ToGenericEnvelope returns a GenericEnvelope version of the current Envelope instance.

type GenericEnvelope

type GenericEnvelope Envelope[Command]

GenericEnvelope is a Command Envelope that depends solely on the Command interface, not a specific generic Command type.

type Handler

type Handler[T Command] interface {
	Handle(ctx context.Context, cmd Envelope[T]) error
}

Handler is the interface that defines a Command Handler, a component that receives a specific kind of Command and executes the business logic related to that particular Command.

type HandlerFunc

type HandlerFunc[T Command] func(context.Context, Envelope[T]) error

HandlerFunc is a functional type that implements the Handler interface. Useful for testing and stateless Handlers.

func (HandlerFunc[T]) Handle

func (fn HandlerFunc[T]) Handle(ctx context.Context, cmd Envelope[T]) error

Handle handles the provided Command through the functional Handler.