improved some of the tasks to use fewer goroutines

email/message.go

@@ -131,22 +131,28 @@ func AmNewEmailMessage(sender int32, ip string) Message {
 	return rc
 }
 
-// recycleMessage cleans out a message and puts it back on the free list.
-func recycleMessage(m *amMessage) {
-	m.from = ""
-	m.fromAddr = ""
-	m.to = make([]string, 0)
-	m.toAddrs = make([]string, 0)
-	m.cc = make([]string, 0)
-	m.bcc = make([]string, 0)
-	m.subject = ""
-	m.text = ""
-	for k := range m.headers {
-		delete(m.headers, k)
+// The "recycle bin" for messages.
+var messageRecycleBin chan *amMessage
+
+// recycleMessages is a goroutine that recycles the messages on its queue.
+func recycleMessages(messages chan *amMessage, done chan bool) {
+	for m := range messages {
+		m.from = ""
+		m.fromAddr = ""
+		m.to = make([]string, 0)
+		m.toAddrs = make([]string, 0)
+		m.cc = make([]string, 0)
+		m.bcc = make([]string, 0)
+		m.subject = ""
+		m.text = ""
+		for k := range m.headers {
+			delete(m.headers, k)
+		}
+		m.template = ""
+		for k := range m.vars {
+			delete(m.vars, k)
+		}
+		freeMessages.Put(m)
 	}
-	m.template = ""
-	for k := range m.vars {
-		delete(m.vars, k)
-	}
-	freeMessages.Put(m)
+	done <- true
 }

email/sender.go

@@ -174,7 +174,7 @@ func senderLoop(sent chan *amMessage, done chan bool) {
 		} else {
 			log.Errorf("unable to format message: %v", err)
 		}
-		go recycleMessage(m)
+		messageRecycleBin <- m
 	}
 	done <- true // signal done for synchronization
 }
@@ -182,9 +182,6 @@ func senderLoop(sent chan *amMessage, done chan bool) {
 // sendChan is the channel we put E-mail messages on to be sent.
 var sendChan chan *amMessage
 
-// doneChan is the channel that gets signaled when the senderLoop breaks.
-var doneChan chan bool
-
 // SetupMailSender starts the mail-sending goroutine.
 func SetupMailSender() func() {
 	// Initialize mail host and authentication.
@@ -207,12 +204,20 @@ func SetupMailSender() func() {
 		jet.DevelopmentMode(true),
 	)
 
+	// Start the recycler.
+	messageRecycleBin = make(chan *amMessage, 16)
+	doneChan1 := make(chan bool)
+	go recycleMessages(messageRecycleBin, doneChan1)
+
 	// Start the sender loop.
 	sendChan = make(chan *amMessage, 16)
-	doneChan = make(chan bool)
-	go senderLoop(sendChan, doneChan)
+	doneChan2 := make(chan bool)
+	go senderLoop(sendChan, doneChan2)
+
 	return func() {
-		close(sendChan) // will break the loop in senderLoop
-		<-doneChan      // wait for routine to complete
+		close(sendChan)
+		<-doneChan2
+		close(messageRecycleBin)
+		<-doneChan1
 	}
 }