update: optimize broadcaster by lazily computing cert entry bytes

internal/broadcast/dispatcher.go

@@ -123,26 +123,21 @@ func (bm *Dispatcher) broadcaster() {
 
 		// Take entry out of broadcast channel and generate JSON representations for the entry.
 		entry := <-bm.MessageQueue
-		dataLite := entry.JSONLite()
-		dataFull := entry.JSON()
-		dataDomain := entry.JSONDomains()
 
 		bm.clientLock.RLock()
 
 		for _, c := range bm.clients {
 			switch c.SubType() {
 			case SubTypeLite:
-				data = dataLite
+				data = entry.JSONLite()
 			case SubTypeFull:
-				data = dataFull
+				data = entry.JSON()
 			case SubTypeDomain:
-				data = dataDomain
+				data = entry.JSONDomains()
 			default:
-				// This should never happen, but if it does, we log it and skip the client.
-				log.Printf("Unknown subscription type '%d' for client '%s'. Skipping this client!\n", c.SubType(), c.Name())
+				log.Printf("Unknown subscription type '%d' on client '%s'. Skipping this client!\n", c.SubType(), c.Name())
 				continue
 			}
-
 			c.Write(data)
 		}
 

internal/models/certstream.go

@@ -7,19 +7,21 @@ import (
 )
 
 type Entry struct {
-	Data           Data   `json:"data"`
-	MessageType    string `json:"message_type"`
-	cachedJSON     []byte
-	cachedJSONLite []byte
+	Data              Data   `json:"data"`
+	MessageType       string `json:"message_type"`
+	cachedJSON        []byte
+	cachedJSONLite    []byte
+	cachedJSONDomains []byte
 }
 
 // Clone returns a new copy of the Entry.
 func (e *Entry) Clone() Entry {
 	return Entry{
-		Data:           e.Data,
-		MessageType:    e.MessageType,
-		cachedJSON:     e.cachedJSON,
-		cachedJSONLite: e.cachedJSONLite,
+		Data:              e.Data,
+		MessageType:       e.MessageType,
+		cachedJSON:        e.cachedJSON,
+		cachedJSONLite:    e.cachedJSONLite,
+		cachedJSONDomains: e.cachedJSONDomains,
 	}
 }
 
@@ -61,6 +63,10 @@ func (e *Entry) JSONLiteNoCache() []byte {
 
 // JSONDomains returns the JSON encoded domains (DomainsEntry) as byte slice.
 func (e *Entry) JSONDomains() []byte {
+	if len(e.cachedJSONDomains) > 0 {
+		return e.cachedJSONDomains
+	}
+
 	domainsEntry := DomainsEntry{
 		Data:        e.Data.LeafCert.AllDomains,
 		MessageType: "dns_entries",
@@ -71,6 +77,8 @@ func (e *Entry) JSONDomains() []byte {
 		log.Println(err)
 	}
 
+	e.cachedJSONDomains = domainsEntryBytes
+
 	return domainsEntryBytes
 }