Add tests for noop event stream

events/event_stream.go

@@ -2,6 +2,7 @@ package events
 
 import (
 	"context"
+	"math/rand"
 	"runtime"
 
 	"github.com/9seconds/mtg/v2/mtglib"
@@ -15,12 +16,20 @@ type eventStream struct {
 }
 
 func (e eventStream) Send(ctx context.Context, evt mtglib.Event) {
-	chanNo := int(xxhash.ChecksumString32(evt.ConnectionID())) % len(e.chans)
+	var chanNo uint32
+
+	streamID := evt.StreamID()
+
+	if streamID == "" {
+		chanNo = rand.Uint32()
+	} else {
+		chanNo = xxhash.ChecksumString32(streamID)
+	}
 
 	select {
 	case <-ctx.Done():
 	case <-e.ctx.Done():
-	case e.chans[chanNo] <- evt:
+	case e.chans[int(chanNo)%len(e.chans)] <- evt:
 	}
 }
 
@@ -29,6 +38,10 @@ func (e eventStream) Shutdown() {
 }
 
 func NewEventStream(observerFactories []ObserverFactory) mtglib.EventStream {
+	if len(observerFactories) == 0 {
+		observerFactories = append(observerFactories, NewNoopObserver)
+	}
+
 	ctx, cancel := context.WithCancel(context.Background())
 	rv := eventStream{
 		ctx:       ctx,
@@ -39,7 +52,11 @@ func NewEventStream(observerFactories []ObserverFactory) mtglib.EventStream {
 	for i := 0; i < runtime.NumCPU(); i++ {
 		rv.chans[i] = make(chan mtglib.Event, 1)
 
-		go eventStreamProcessor(ctx, rv.chans[i], newMultiObserver(observerFactories))
+		if len(observerFactories) == 1 {
+			go eventStreamProcessor(ctx, rv.chans[i], observerFactories[0]())
+		} else {
+			go eventStreamProcessor(ctx, rv.chans[i], newMultiObserver(observerFactories))
+		}
 	}
 
 	return rv
@@ -58,6 +75,8 @@ func eventStreamProcessor(ctx context.Context, eventChan <-chan mtglib.Event, ob
 				observer.EventStart(typedEvt)
 			case mtglib.EventFinish:
 				observer.EventFinish(typedEvt)
+			case mtglib.EventConcurrencyLimited:
+				observer.EventConcurrencyLimited(typedEvt)
 			}
 		}
 	}

events/init.go

@@ -5,6 +5,7 @@ import "github.com/9seconds/mtg/v2/mtglib"
 type Observer interface {
 	EventStart(mtglib.EventStart)
 	EventFinish(mtglib.EventFinish)
+    EventConcurrencyLimited(mtglib.EventConcurrencyLimited)
 
 	Shutdown()
 }

events/init_test.go

@@ -17,6 +17,10 @@ func (o *ObserverMock) EventFinish(evt mtglib.EventStart) {
 	o.Called(evt)
 }
 
+func (o *ObserverMock) EventConcurrencyLimited(evt mtglib.EventConcurrencyLimited) {
+	o.Called(evt)
+}
+
 func (o *ObserverMock) Shutdown() {
 	o.Called()
 }

events/multi_observer.go

@@ -40,6 +40,21 @@ func (m multiObserver) EventFinish(evt mtglib.EventFinish) {
 	wg.Wait()
 }
 
+func (m multiObserver) EventConcurrencyLimited(evt mtglib.EventConcurrencyLimited) {
+	wg := &sync.WaitGroup{}
+	wg.Add(len(m.observers))
+
+	for _, v := range m.observers {
+		go func(obs Observer) {
+			defer wg.Done()
+
+			obs.EventConcurrencyLimited(evt)
+		}(v)
+	}
+
+	wg.Wait()
+}
+
 func (m multiObserver) Shutdown() {
 	for _, v := range m.observers {
 		v.Shutdown()

events/noop.go

@@ -0,0 +1,27 @@
+package events
+
+import (
+	"context"
+
+	"github.com/9seconds/mtg/v2/mtglib"
+)
+
+type noop struct{}
+
+func (n noop) Send(ctx context.Context, evt mtglib.Event) {}
+func (n noop) Shutdown()                                  {}
+
+func NewNoopStream() mtglib.EventStream {
+	return noop{}
+}
+
+type noopObserver struct{}
+
+func (n noopObserver) EventStart(_ mtglib.EventStart)                           {}
+func (n noopObserver) EventFinish(_ mtglib.EventFinish)                         {}
+func (n noopObserver) EventConcurrencyLimited(_ mtglib.EventConcurrencyLimited) {}
+func (n noopObserver) Shutdown()                                                {}
+
+func NewNoopObserver() Observer {
+	return noopObserver{}
+}

events/noop_test.go

@@ -0,0 +1,75 @@
+package events_test
+
+import (
+	"context"
+	"net"
+	"testing"
+	"time"
+
+	"github.com/9seconds/mtg/v2/events"
+	"github.com/9seconds/mtg/v2/mtglib"
+	"github.com/stretchr/testify/suite"
+)
+
+type NoopTestSuite struct {
+	suite.Suite
+
+	testData map[string]mtglib.Event
+	ctx      context.Context
+}
+
+func (suite *NoopTestSuite) SetupSuite() {
+	suite.testData = map[string]mtglib.Event{
+		"start": mtglib.EventStart{
+			CreatedAt: time.Now(),
+			ConnID:    "connID",
+			RemoteIP:  net.ParseIP("127.0.0.1"),
+		},
+		"finish": mtglib.EventFinish{
+			CreatedAt: time.Now(),
+			ConnID:    "connID",
+		},
+		"concurrency-limited": mtglib.EventConcurrencyLimited{},
+	}
+	suite.ctx = context.Background()
+}
+
+func (suite *NoopTestSuite) TestStream() {
+	stream := events.NewNoopStream()
+
+	for name, v := range suite.testData {
+		value := v
+
+		suite.T().Run(name, func(t *testing.T) {
+			stream.Send(suite.ctx, value)
+		})
+	}
+
+	stream.Shutdown()
+}
+
+func (suite *NoopTestSuite) TestObserver() {
+	observer := events.NewNoopObserver()
+
+	for name, v := range suite.testData {
+		value := v
+
+		suite.T().Run(name, func(t *testing.T) {
+			switch typedEvt := value.(type) {
+			case mtglib.EventStart:
+				observer.EventStart(typedEvt)
+			case mtglib.EventFinish:
+				observer.EventFinish(typedEvt)
+			case mtglib.EventConcurrencyLimited:
+				observer.EventConcurrencyLimited(typedEvt)
+			}
+		})
+	}
+
+	observer.Shutdown()
+}
+
+func TestNoop(t *testing.T) {
+	t.Parallel()
+	suite.Run(t, &NoopTestSuite{})
+}

mtglib/events.go

@@ -5,21 +5,27 @@ import (
 	"time"
 )
 
-type eventBase struct {
+type EventStart struct {
+	CreatedAt time.Time
+	ConnID    string
+	RemoteIP  net.IP
+}
+
+func (e EventStart) StreamID() string {
+	return e.ConnID
+}
+
+type EventFinish struct {
 	CreatedAt time.Time
 	ConnID    string
 }
 
-func (e eventBase) ConnectionID() string {
+func (e EventFinish) StreamID() string {
 	return e.ConnID
 }
 
-type EventStart struct {
+type EventConcurrencyLimited struct{}
-	eventBase
 
-	RemoteIP net.IP
+func (e EventConcurrencyLimited) StreamID() string {
-}
+	return ""
-
-type EventFinish struct {
-	eventBase
 }

mtglib/init.go

@@ -28,7 +28,7 @@ type IPBlocklist interface {
 }
 
 type Event interface {
-	ConnectionID() string
+	StreamID() string
 }
 
 type EventStream interface {