Implement Disable() on handler configurers.

aggregate.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"reflect"
 
-	"github.com/dogmatiq/configkit/message"
 	"github.com/dogmatiq/dogma"
 )
 
@@ -28,9 +27,17 @@ type RichAggregate interface {
 // It panics if the handler is configured incorrectly. Use Recover() to convert
 // configuration related panic values to errors.
 func FromAggregate(h dogma.AggregateMessageHandler) RichAggregate {
+	cfg, c := fromAggregate(h)
+	c.mustValidate()
+	return cfg
+}
+
+func fromAggregate(h dogma.AggregateMessageHandler) (*aggregate, *aggregateConfigurer) {
 	cfg := &aggregate{
-		entity: entity{
-			rt: reflect.TypeOf(h),
+		handler: handler{
+			entity: entity{
+				rt: reflect.TypeOf(h),
+			},
 		},
 		impl: h,
 	}
@@ -40,21 +47,18 @@ func FromAggregate(h dogma.AggregateMessageHandler) RichAggregate {
 			entityConfigurer: entityConfigurer{
 				entity: &cfg.entity,
 			},
+			handler: &cfg.handler,
 		},
 	}
 
 	h.Configure(c)
 
-	c.validate()
-	c.mustConsume(message.CommandRole)
-	c.mustProduce(message.EventRole)
-
-	return cfg
+	return cfg, c
 }
 
 // aggregate is an implementation of RichAggregate.
 type aggregate struct {
-	entity
+	handler
 
 	impl dogma.AggregateMessageHandler
 }

aggregate_test.go

@@ -34,7 +34,7 @@ var _ = Describe("func FromAggregate()", func() {
 	When("the configuration is valid", func() {
 		var cfg RichAggregate
 
-		BeforeEach(func() {
+		JustBeforeEach(func() {
 			cfg = FromAggregate(handler)
 		})
 
@@ -124,11 +124,33 @@ var _ = Describe("func FromAggregate()", func() {
 			})
 		})
 
+		Describe("func IsDisabled()", func() {
+			It("returns false", func() {
+				Expect(cfg.IsDisabled()).To(BeFalse())
+			})
+		})
+
 		Describe("func Handler()", func() {
 			It("returns the underlying handler", func() {
 				Expect(cfg.Handler()).To(BeIdenticalTo(handler))
 			})
 		})
+
+		When("the handler is disabled", func() {
+			BeforeEach(func() {
+				configure := handler.ConfigureFunc
+				handler.ConfigureFunc = func(c dogma.AggregateConfigurer) {
+					configure(c)
+					c.Disable()
+				}
+			})
+
+			Describe("func IsDisabled()", func() {
+				It("returns true", func() {
+					Expect(cfg.IsDisabled()).To(BeTrue())
+				})
+			})
+		})
 	})
 
 	DescribeTable(

aggregateconfigurer.go

@@ -1,6 +1,9 @@
 package configkit
 
-import "github.com/dogmatiq/dogma"
+import (
+	"github.com/dogmatiq/configkit/message"
+	"github.com/dogmatiq/dogma"
+)
 
 type aggregateConfigurer struct {
 	handlerConfigurer
@@ -11,3 +14,9 @@ func (c *aggregateConfigurer) Routes(routes ...dogma.AggregateRoute) {
 		c.route(r)
 	}
 }
+
+func (c *aggregateConfigurer) mustValidate() {
+	c.handlerConfigurer.mustValidate()
+	c.mustConsume(message.CommandRole)
+	c.mustProduce(message.EventRole)
+}

api/blackbox_test.go

@@ -77,6 +77,7 @@ var _ = Context("end-to-end tests", func() {
 							dogma.HandlesEvent[MessageE](),
 							dogma.HandlesEvent[MessageJ](),
 						)
+						c.Disable()
 					},
 				})
 			},

api/marshaling.go

@@ -82,7 +82,9 @@ func unmarshalApplication(in *configspec.Application) (configkit.Application, er
 
 // marshalHandler marshals a handler config to its protobuf representation.
 func marshalHandler(in configkit.Handler) (*configspec.Handler, error) {
-	out := &configspec.Handler{}
+	out := &configspec.Handler{
+		IsDisabled: in.IsDisabled(),
+	}
 
 	var err error
 	out.Identity, err = marshalIdentity(in.Identity())
@@ -122,6 +124,7 @@ func unmarshalHandler(in *configspec.Handler) (configkit.Handler, error) {
 			Produced: message.NameRoles{},
 			Consumed: message.NameRoles{},
 		},
+		IsDisabledValue: in.GetIsDisabled(),
 	}
 
 	var err error

application.go

@@ -36,6 +36,12 @@ type RichApplication interface {
 // It panics if the application is configured incorrectly. Use Recover() to
 // convert configuration related panic values to errors.
 func FromApplication(a dogma.Application) RichApplication {
+	cfg, c := fromApplication(a)
+	c.mustValidate()
+	return cfg
+}
+
+func fromApplication(a dogma.Application) (*application, *applicationConfigurer) {
 	cfg := &application{
 		entity: entity{
 			rt: reflect.TypeOf(a),
@@ -52,9 +58,7 @@ func FromApplication(a dogma.Application) RichApplication {
 
 	a.Configure(c)
 
-	c.validate()
-
-	return cfg
+	return cfg, c
 }
 
 // IsApplicationEqual compares two applications for equality.

application_test.go

@@ -68,13 +68,23 @@ var _ = Describe("func FromApplication()", func() {
 			},
 		}
 
+		disabled := &fixtures.ProjectionMessageHandler{
+			ConfigureFunc: func(c dogma.ProjectionConfigurer) {
+				// Verify that disabled handlers with no identity / route
+				// configuration are excluded from the application
+				// configuration.
+				c.Disable()
+			},
+		}
+
 		app = &fixtures.Application{
 			ConfigureFunc: func(c dogma.ApplicationConfigurer) {
 				c.Identity("<app>", appKey)
 				c.RegisterAggregate(aggregate)
 				c.RegisterProcess(process)
 				c.RegisterIntegration(integration)
 				c.RegisterProjection(projection)
+				c.RegisterProjection(disabled)
 			},
 		}
 	})

applicationconfigurer.go

@@ -27,27 +27,35 @@ func (c *applicationConfigurer) Identity(name, key string) {
 }
 
 func (c *applicationConfigurer) RegisterAggregate(h dogma.AggregateMessageHandler, _ ...dogma.RegisterAggregateOption) {
-	cfg := FromAggregate(h)
-	c.register(cfg)
+	c.registerIfConfigured(fromAggregate(h))
 }
 
 func (c *applicationConfigurer) RegisterProcess(h dogma.ProcessMessageHandler, _ ...dogma.RegisterProcessOption) {
-	cfg := FromProcess(h)
-	c.register(cfg)
+	c.registerIfConfigured(fromProcess(h))
 }
 
 func (c *applicationConfigurer) RegisterIntegration(h dogma.IntegrationMessageHandler, _ ...dogma.RegisterIntegrationOption) {
-	cfg := FromIntegration(h)
-	c.register(cfg)
+	c.registerIfConfigured(fromIntegration(h))
 }
 
 func (c *applicationConfigurer) RegisterProjection(h dogma.ProjectionMessageHandler, _ ...dogma.RegisterProjectionOption) {
-	cfg := FromProjection(h)
-	c.register(cfg)
+	c.registerIfConfigured(fromProjection(h))
 }
 
 // register adds a handler configuration to the application.
-func (c *applicationConfigurer) register(h RichHandler) {
+func (c *applicationConfigurer) registerIfConfigured(
+	h RichHandler,
+	hc interface {
+		isConfigured() bool
+		mustValidate()
+	},
+) {
+	if h.IsDisabled() && !hc.isConfigured() {
+		return
+	}
+
+	hc.mustValidate()
+
 	c.guardAgainstConflictingIdentities(h)
 	c.guardAgainstConflictingRoles(h)
 	c.guardAgainstConflictingRoutes(h)

entityconfigurer.go

@@ -12,11 +12,14 @@ import "github.com/dogmatiq/configkit/internal/validation"
 //   - [dogma.ProjectionConfigurer]
 type entityConfigurer struct {
 	// entity is the target entity to populate with the configuration values.
-	entity *entity
+	entity     *entity
+	configured bool
 }
 
 // Identity sets the entity's identity.
 func (c *entityConfigurer) Identity(n string, k string) {
+	c.configured = true
+
 	if !c.entity.ident.IsZero() {
 		validation.Panicf(
 			"%s is configured with multiple identities (%s and %s/%s), Identity() must be called exactly once within Configure()",
@@ -39,8 +42,12 @@ func (c *entityConfigurer) Identity(n string, k string) {
 	}
 }
 
-// validate panics if the configuration is invalid.
-func (c *entityConfigurer) validate() {
+func (c *entityConfigurer) isConfigured() bool {
+	return c.configured
+}
+
+// mustValidate panics if the configuration is invalid.
+func (c *entityConfigurer) mustValidate() {
 	if c.entity.ident.IsZero() {
 		validation.Panicf(
 			"%s is configured without an identity, Identity() must be called exactly once within Configure()",

go.mod

@@ -3,9 +3,9 @@ module github.com/dogmatiq/configkit
 go 1.21
 
 require (
-	github.com/dogmatiq/dogma v0.13.0
+	github.com/dogmatiq/dogma v0.13.1
 	github.com/dogmatiq/iago v0.4.0
-	github.com/dogmatiq/interopspec v0.5.3
+	github.com/dogmatiq/interopspec v0.5.4
 	github.com/emicklei/dot v1.6.2
 	github.com/google/uuid v1.6.0
 	github.com/onsi/ginkgo v1.16.5
@@ -25,7 +25,7 @@ require (
 	golang.org/x/sys v0.22.0 // indirect
 	golang.org/x/text v0.16.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20240528184218-531527333157 // indirect
-	google.golang.org/protobuf v1.34.1 // indirect
+	google.golang.org/protobuf v1.34.2 // indirect
 	gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,12 +1,12 @@
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/dogmatiq/dogma v0.13.0 h1:MKk9MHErGKD53Y+43I4fcoPZMQjX0N2DUZEc4rLp+Hk=
-github.com/dogmatiq/dogma v0.13.0/go.mod h1:9lyVA+6V2+E/exV0IrBOrkUiyFwIATEhv+b0vnB2umQ=
+github.com/dogmatiq/dogma v0.13.1 h1:b1nsqYNmICEG2egvZ43K8w04Jma+MWYL6yF5Ad12y9o=
+github.com/dogmatiq/dogma v0.13.1/go.mod h1:9lyVA+6V2+E/exV0IrBOrkUiyFwIATEhv+b0vnB2umQ=
 github.com/dogmatiq/iago v0.4.0 h1:57nZqVT34IZxtCZEW/RFif7DNUEjMXgevfr/Mmd0N8I=
 github.com/dogmatiq/iago v0.4.0/go.mod h1:fishMWBtzYcjgis6d873VTv9kFm/wHYLOzOyO9ECBDc=
-github.com/dogmatiq/interopspec v0.5.3 h1:AES184nLWcek8/vafykZJLmm59NlRiYiC40Tll8hEeg=
-github.com/dogmatiq/interopspec v0.5.3/go.mod h1:3RdRwvDzgqLwemSieP+YAvKp3CMP0rYwZFl5tpmn6DI=
+github.com/dogmatiq/interopspec v0.5.4 h1:klyGPy16zUKJartJIJOBZ4JrQ4LxFiY3wgzFTTiNlDk=
+github.com/dogmatiq/interopspec v0.5.4/go.mod h1:JL0QFXBTRGH+RgQqExhEUdhtv5Vn802w43RxKQbk8Co=
 github.com/emicklei/dot v1.6.2 h1:08GN+DD79cy/tzN6uLCT84+2Wk9u+wvqP+Hkx/dIR8A=
 github.com/emicklei/dot v1.6.2/go.mod h1:DeV7GvQtIw4h2u73RKBkkFdvVAz0D9fzeJrgPW6gy/s=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
@@ -110,8 +110,8 @@ google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQ
 google.golang.org/protobuf v1.20.1-0.20200309200217-e05f789c0967/go.mod h1:A+miEFZTKqfCUM6K7xSMQL9OKL/b6hQv+e19PK+JZNE=
 google.golang.org/protobuf v1.21.0/go.mod h1:47Nbq4nVaFHyn7ilMalzfO3qCViNmqZ2kzikPIcrTAo=
 google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
-google.golang.org/protobuf v1.34.1 h1:9ddQBjfCyZPOHPUiPxpYESBLc+T8P3E+Vo4IbKZgFWg=
-google.golang.org/protobuf v1.34.1/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
+google.golang.org/protobuf v1.34.2 h1:6xV6lTsCfpGD21XK49h7MhtcApnLqkfYgPcdHftf6hg=
+google.golang.org/protobuf v1.34.2/go.mod h1:qYOHts0dSfpeUzUFpOMr/WGzszTmLH+DiWniOlNbLDw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

handler.go

@@ -6,6 +6,9 @@ type Handler interface {
 
 	// HandlerType returns the type of handler.
 	HandlerType() HandlerType
+
+	// IsDisabled returns true if the handler is disabled.
+	IsDisabled() bool
 }
 
 // RichHandler is a specialization of the Handler interface that exposes
@@ -15,6 +18,9 @@ type RichHandler interface {
 
 	// HandlerType returns the type of handler.
 	HandlerType() HandlerType
+
+	// IsDisabled returns true if the handler is disabled.
+	IsDisabled() bool
 }
 
 // IsHandlerEqual compares two handlers for equality.
@@ -36,5 +42,15 @@ func IsHandlerEqual(a, b Handler) bool {
 	return a.Identity() == b.Identity() &&
 		a.TypeName() == b.TypeName() &&
 		a.HandlerType() == b.HandlerType() &&
+		a.IsDisabled() == b.IsDisabled() &&
 		a.MessageNames().IsEqual(b.MessageNames())
 }
+
+type handler struct {
+	entity
+	isDisabled bool
+}
+
+func (h *handler) IsDisabled() bool {
+	return h.isDisabled
+}

handler_test.go

@@ -85,6 +85,20 @@ var _ = Describe("func IsHandlerEqual()", func() {
 				},
 			}),
 		),
+		Entry(
+			"disabled state differs",
+			FromAggregate(&fixtures.AggregateMessageHandler{
+				ConfigureFunc: func(c dogma.AggregateConfigurer) {
+					c.Identity("<name>", aggregateKey)
+					c.Routes(
+						dogma.HandlesCommand[fixtures.MessageA](),
+						dogma.HandlesCommand[fixtures.MessageB](),
+						dogma.RecordsEvent[fixtures.MessageE](),
+					)
+					c.Disable()
+				},
+			}),
+		),
 		Entry(
 			"messages differ",
 			FromAggregate(&fixtures.AggregateMessageHandler{

handlerconfigurer.go

@@ -19,9 +19,16 @@ import (
 //   - [dogma.ProjectionConfigurer]
 type handlerConfigurer struct {
 	entityConfigurer
+	handler *handler
+}
+
+func (c *handlerConfigurer) Disable(...dogma.DisableOption) {
+	c.handler.isDisabled = true
 }
 
 func (c *handlerConfigurer) route(r dogma.Route) {
+	c.configured = true
+
 	switch r := r.(type) {
 	case dogma.HandlesCommandRoute:
 		c.consumes(r.Type, message.CommandRole, "HandlesCommand")