Keep event history in circular buffer

Storing event history in a circular buffer avoids memory allocation after the storage limit is reached.

- Minor fixes to storage history logic
- Order message type switch to check for most common messages first
- Minor code improvements

go.mod

@@ -1,8 +1,9 @@
 module github.com/gammazero/nexus/v3
 
-go 1.20
+go 1.21
 
 require (
+	github.com/gammazero/deque v0.2.1
 	github.com/gorilla/websocket v1.5.0
 	github.com/stretchr/testify v1.8.4
 	github.com/ugorji/go/codec v1.2.11

go.sum

@@ -1,9 +1,12 @@
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/gammazero/deque v0.2.1 h1:qSdsbG6pgp6nL7A0+K/B7s12mcCY/5l5SIUpMOl+dC0=
+github.com/gammazero/deque v0.2.1/go.mod h1:LFroj8x4cMYCukHJDbxFCkT+r9AndaJnFMuZDV34tuU=
 github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
 github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
+github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -18,5 +21,6 @@ golang.org/x/crypto v0.17.0 h1:r8bRNjWL3GshPW3gkd+RpvzWrZAwPS49OmTGZ/uhM4k=
 golang.org/x/crypto v0.17.0/go.mod h1:gCAAfMLgwOJRpTjQ2zCCt2OcSfYMTeZVSRtQlPC7Nq4=
 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=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

router/broker.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/gammazero/deque"
 	"github.com/gammazero/nexus/v3/stdlog"
 	"github.com/gammazero/nexus/v3/wamp"
 )
@@ -52,10 +53,13 @@ type historyEntry struct {
 }
 
 type historyStore struct {
-	entries        []historyEntry
-	matchPolicy    string
-	limit          int
-	isLimitReached bool
+	entries     deque.Deque[historyEntry]
+	matchPolicy string
+	limit       int
+}
+
+func (h *historyStore) atLimit() bool {
+	return h.entries.Len() >= h.limit
 }
 
 type broker struct {
@@ -149,10 +153,8 @@ func (b *broker) PreInitEventHistoryTopics(evntCfgs []*TopicEventHistoryConfig)
 		sub, _ := b.syncInitSubscription(topicCfg.Topic, topicCfg.MatchPolicy, nil)
 
 		b.eventHistoryStore[sub] = &historyStore{
-			entries:        []historyEntry{},
-			matchPolicy:    topicCfg.MatchPolicy,
-			limit:          topicCfg.Limit,
-			isLimitReached: false,
+			matchPolicy: topicCfg.MatchPolicy,
+			limit:       topicCfg.Limit,
 		}
 
 	}
@@ -383,12 +385,8 @@ func newSubscription(id wamp.ID, subscriber *wamp.Session, topic wamp.URI, match
 }
 
 func (b *broker) syncSaveEvent(eventStore *historyStore, pub *wamp.Publish, event *wamp.Event) {
-
-	if eventStore.isLimitReached {
-		eventStore.entries = eventStore.entries[1:]
-	} else if len(eventStore.entries) >= eventStore.limit {
-		eventStore.isLimitReached = true
-		eventStore.entries = eventStore.entries[1:]
+	if eventStore.atLimit() {
+		eventStore.entries.PopFront()
 	}
 
 	item := historyEntry{
@@ -403,7 +401,7 @@ func (b *broker) syncSaveEvent(eventStore *historyStore, pub *wamp.Publish, even
 		},
 	}
 
-	eventStore.entries = append(eventStore.entries, item)
+	eventStore.entries.PushBack(item)
 }
 
 func (b *broker) syncInitSubscription(topic wamp.URI, match string, subscriber *wamp.Session) (sub *subscription, existingSub bool) {
@@ -1138,7 +1136,7 @@ func (b *broker) subEventHistory(msg *wamp.Invocation) wamp.Message {
 
 	fromPubOp, ok := msg.ArgumentsKw["from_publication"]
 	if ok {
-		fromPub = fromPubOp.(wamp.ID)
+		fromPub, ok = fromPubOp.(wamp.ID)
 		if !ok || fromPub < 1 {
 			return &wamp.Error{
 				Type:    msg.MessageType(),
@@ -1152,7 +1150,7 @@ func (b *broker) subEventHistory(msg *wamp.Invocation) wamp.Message {
 
 	afterPubOp, ok := msg.ArgumentsKw["after_publication"]
 	if ok {
-		afterPub = afterPubOp.(wamp.ID)
+		afterPub, ok = afterPubOp.(wamp.ID)
 		if !ok || afterPub < 1 {
 			return &wamp.Error{
 				Type:    msg.MessageType(),
@@ -1165,7 +1163,7 @@ func (b *broker) subEventHistory(msg *wamp.Invocation) wamp.Message {
 
 	beforePubOp, ok := msg.ArgumentsKw["before_publication"]
 	if ok {
-		beforePub = beforePubOp.(wamp.ID)
+		beforePub, ok = beforePubOp.(wamp.ID)
 		if !ok || beforePub < 1 {
 			return &wamp.Error{
 				Type:    msg.MessageType(),
@@ -1178,7 +1176,7 @@ func (b *broker) subEventHistory(msg *wamp.Invocation) wamp.Message {
 
 	untilPubOp, ok := msg.ArgumentsKw["until_publication"]
 	if ok {
-		untilPub = untilPubOp.(wamp.ID)
+		untilPub, ok = untilPubOp.(wamp.ID)
 		if !ok || untilPub < 1 {
 			return &wamp.Error{
 				Type:    msg.MessageType(),
@@ -1189,19 +1187,20 @@ func (b *broker) subEventHistory(msg *wamp.Invocation) wamp.Message {
 		}
 	}
 
-	ch := make(chan struct{})
+	done := make(chan struct{})
 	b.actionChan <- func() {
+		defer close(done)
+
 		var filteredEvents []storedEvent
 
 		if subscription, ok := b.subscriptions[subId]; ok {
 			if storeItem, ok := b.eventHistoryStore[subscription]; ok {
-				isLimitReached = storeItem.isLimitReached
+				isLimitReached = storeItem.atLimit()
 
-				fromPubReached := false
-				afterPubReached := false
-				untilPubReached := false
+				var untilPubReached bool
 
-				for _, entry := range storeItem.entries {
+				for i := 0; i < storeItem.entries.Len(); i++ {
+					entry := storeItem.entries.At(i)
 					if !fromDate.IsZero() && entry.event.timestamp.Before(fromDate) {
 						continue
 					}
@@ -1214,20 +1213,17 @@ func (b *broker) subEventHistory(msg *wamp.Invocation) wamp.Message {
 					if !untilDate.IsZero() && entry.event.timestamp.After(untilDate) {
 						continue
 					}
-					if fromPub > 0 && !fromPubReached {
+					if fromPub != 0 {
 						if entry.event.Publication != fromPub {
 							continue
-						} else {
-							fromPubReached = true
 						}
+						fromPub = 0
 					}
-					if afterPub > 0 && !afterPubReached {
-						if entry.event.Publication != afterPub {
-							continue
-						} else {
-							afterPubReached = true
-							continue
+					if afterPub != 0 {
+						if entry.event.Publication == afterPub {
+							afterPub = 0
 						}
+						continue
 					}
 					if beforePub > 0 && entry.event.Publication == beforePub {
 						break
@@ -1270,9 +1266,8 @@ func (b *broker) subEventHistory(msg *wamp.Invocation) wamp.Message {
 		}
 
 		events, _ = wamp.AsList(filteredEvents)
-		close(ch)
 	}
-	<-ch
+	<-done
 
 	return &wamp.Yield{
 		Request:     msg.Request,

router/broker_test.go

@@ -699,48 +699,48 @@ func TestEventHistory(t *testing.T) {
 	topic := wamp.URI("nexus.test.exact.topic")
 	subscription := broker.topicSubscription[topic]
 	subEvents := broker.eventHistoryStore[subscription].entries
-	require.Equalf(t, 3, len(subEvents), "Store for topic %s should hold 3 records", topic)
-	require.Truef(t, broker.eventHistoryStore[subscription].isLimitReached, "Limit for the store for topic %s should be reached", topic)
-	require.Equalf(t, "nexus.test.exact.topic", subEvents[0].event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, 25509, subEvents[0].event.Arguments[0], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, "nexus.test.exact.topic", subEvents[1].event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, 25513, subEvents[1].event.Arguments[0], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, "nexus.test.exact.topic", subEvents[2].event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, 25517, subEvents[2].event.Arguments[0], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 3, subEvents.Len(), "Store for topic %s should hold 3 records", topic)
+	require.Truef(t, broker.eventHistoryStore[subscription].atLimit(), "Limit for the store for topic %s should be reached", topic)
+	require.Equalf(t, "nexus.test.exact.topic", subEvents.At(0).event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 25509, subEvents.At(0).event.Arguments[0], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, "nexus.test.exact.topic", subEvents.At(1).event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 25513, subEvents.At(1).event.Arguments[0], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, "nexus.test.exact.topic", subEvents.At(2).event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 25517, subEvents.At(2).event.Arguments[0], "Event store for topic %s holds invalid event", topic)
 
 	topic = wamp.URI("nexus.test")
 	subscription = broker.pfxTopicSubscription[topic]
 	subEvents = broker.eventHistoryStore[subscription].entries
-	require.Equalf(t, 4, len(subEvents), "Store for topic %s should hold 3 records", topic)
-	require.Truef(t, broker.eventHistoryStore[subscription].isLimitReached, "Limit for the store for topic %s should be reached", topic)
-	require.Equalf(t, "nexus.test.exact.topic", subEvents[0].event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, 25517, subEvents[0].event.Arguments[0], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, "nexus.test.prefix.catch", subEvents[1].event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, 25518, subEvents[1].event.Arguments[0], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, "nexus.test.wildcard.topic", subEvents[2].event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, 25519, subEvents[2].event.Arguments[0], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, "nexus.test.wildcard.miss", subEvents[3].event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, 25520, subEvents[3].event.Arguments[0], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 4, subEvents.Len(), "Store for topic %s should hold 3 records", topic)
+	require.Truef(t, broker.eventHistoryStore[subscription].atLimit(), "Limit for the store for topic %s should be reached", topic)
+	require.Equalf(t, "nexus.test.exact.topic", subEvents.At(0).event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 25517, subEvents.At(0).event.Arguments[0], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, "nexus.test.prefix.catch", subEvents.At(1).event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 25518, subEvents.At(1).event.Arguments[0], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, "nexus.test.wildcard.topic", subEvents.At(2).event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 25519, subEvents.At(2).event.Arguments[0], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, "nexus.test.wildcard.miss", subEvents.At(3).event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 25520, subEvents.At(3).event.Arguments[0], "Event store for topic %s holds invalid event", topic)
 
 	topic = wamp.URI("nexus.test..topic")
 	subscription = broker.wcTopicSubscription[topic]
 	subEvents = broker.eventHistoryStore[subscription].entries
-	require.Equalf(t, 4, len(subEvents), "Store for topic %s should hold 3 records", topic)
-	require.Truef(t, broker.eventHistoryStore[subscription].isLimitReached, "Limit for the store for topic %s should be reached", topic)
-	require.Equalf(t, "nexus.test.exact.topic", subEvents[0].event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, 25513, subEvents[0].event.Arguments[0], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, "nexus.test.wildcard.topic", subEvents[1].event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, 25515, subEvents[1].event.Arguments[0], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, "nexus.test.exact.topic", subEvents[2].event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, 25517, subEvents[2].event.Arguments[0], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, "nexus.test.wildcard.topic", subEvents[3].event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
-	require.Equalf(t, 25519, subEvents[3].event.Arguments[0], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 4, subEvents.Len(), "Store for topic %s should hold 3 records", topic)
+	require.Truef(t, broker.eventHistoryStore[subscription].atLimit(), "Limit for the store for topic %s should be reached", topic)
+	require.Equalf(t, "nexus.test.exact.topic", subEvents.At(0).event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 25513, subEvents.At(0).event.Arguments[0], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, "nexus.test.wildcard.topic", subEvents.At(1).event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 25515, subEvents.At(1).event.Arguments[0], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, "nexus.test.exact.topic", subEvents.At(2).event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 25517, subEvents.At(2).event.Arguments[0], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, "nexus.test.wildcard.topic", subEvents.At(3).event.ArgumentsKw["topic"], "Event store for topic %s holds invalid event", topic)
+	require.Equalf(t, 25519, subEvents.At(3).event.Arguments[0], "Event store for topic %s holds invalid event", topic)
 
 	topic = wamp.URI("nexus")
 	subscription = broker.pfxTopicSubscription[topic]
 	subEvents = broker.eventHistoryStore[subscription].entries
-	require.Equalf(t, 20, len(subEvents), "Store for topic %s should hold 20 records", topic)
-	require.Falsef(t, broker.eventHistoryStore[subscription].isLimitReached, "Limit for the store for topic %s should not be reached", topic)
+	require.Equalf(t, 20, subEvents.Len(), "Store for topic %s should hold 20 records", topic)
+	require.Falsef(t, broker.eventHistoryStore[subscription].atLimit(), "Limit for the store for topic %s should not be reached", topic)
 
 	//Now let's test Event History MetaRPCs
 	topic = wamp.URI("nexus.test.exact.topic")
@@ -885,7 +885,7 @@ func TestEventHistory(t *testing.T) {
 	// Let's test filtering based on publication ID
 	topic = wamp.URI("nexus")
 	subscription = broker.pfxTopicSubscription[topic]
-	pubId := broker.eventHistoryStore[subscription].entries[4].event.Publication
+	pubId := broker.eventHistoryStore[subscription].entries.At(4).event.Publication
 	inv = wamp.Invocation{
 		Request:      wamp.ID(reqId),
 		Registration: 0,

router/realm.go

@@ -472,21 +472,20 @@ func (r *realm) handleInboundMessages(sess *wamp.Session) (bool, bool, error) {
 		switch msg := msg.(type) {
 		case *wamp.Publish:
 			r.broker.publish(sess, msg)
+		case *wamp.Yield:
+			r.dealer.yield(sess, msg)
+		case *wamp.Call:
+			r.dealer.call(sess, msg)
+		case *wamp.Cancel:
+			r.dealer.cancel(sess, msg)
 		case *wamp.Subscribe:
 			r.broker.subscribe(sess, msg)
-		case *wamp.Unsubscribe:
-			r.broker.unsubscribe(sess, msg)
-
 		case *wamp.Register:
 			r.dealer.register(sess, msg)
+		case *wamp.Unsubscribe:
+			r.broker.unsubscribe(sess, msg)
 		case *wamp.Unregister:
 			r.dealer.unregister(sess, msg)
-		case *wamp.Call:
-			r.dealer.call(sess, msg)
-		case *wamp.Yield:
-			r.dealer.yield(sess, msg)
-		case *wamp.Cancel:
-			r.dealer.cancel(sess, msg)
 
 		case *wamp.Error:
 			// An INVOCATION error is the only type of ERROR message the

wamp/session.go

@@ -71,22 +71,21 @@ func (s *Session) HasFeature(role, feature string) bool {
 // by calling EndRecv.
 func (s *Session) RecvDone() <-chan struct{} {
 	s.mu.Lock()
+	defer s.mu.Unlock()
+
 	if s.done == nil {
 		s.done = make(chan struct{})
 	}
-	d := s.done
-	s.mu.Unlock()
-	return d
+	return s.done
 }
 
 // If RecvDone is not yet closed, Goodbye returns nil.
 // If RecvDone is closed, Goodbye returns the GOODBYE message that was supplied
 // when RecvEnd was called.
 func (s *Session) Goodbye() *Goodbye {
 	s.mu.Lock()
-	g := s.goodbye
-	s.mu.Unlock()
-	return g
+	defer s.mu.Unlock()
+	return s.goodbye
 }
 
 // EndRecv tells the session to signal messages handlers to stop receiving
@@ -96,8 +95,9 @@ func (s *Session) Goodbye() *Goodbye {
 // with exiting the message handler for other reasons.
 func (s *Session) EndRecv(goodbye *Goodbye) bool {
 	s.mu.Lock()
+	defer s.mu.Unlock()
+
 	if s.goodbye != nil {
-		s.mu.Unlock()
 		return false // already ended
 	}
 
@@ -112,7 +112,6 @@ func (s *Session) EndRecv(goodbye *Goodbye) bool {
 	}
 	close(s.done)
 
-	s.mu.Unlock()
 	return true
 }