USR1 on circologd pause/resume

cmd/circologd/main.go

@@ -31,7 +31,7 @@ func main() {
 	flag.Parse()
 
 	interrupt := make(chan os.Signal, 1)
-	signal.Notify(interrupt, syscall.SIGINT, syscall.SIGHUP, syscall.SIGTERM)
+	signal.Notify(interrupt, syscall.SIGINT, syscall.SIGHUP, syscall.SIGUSR1, syscall.SIGTERM)
 
 	hub := circolog.NewHub(*bufsize)
 	handler := syslog.NewChannelHandler(hub.LogMessages)
@@ -90,7 +90,11 @@ func main() {
 		case sig := <-interrupt:
 			if sig == syscall.SIGHUP {
 				log.Println("Clearing queue")
-				hub.Clear()
+				hub.Commands <- circolog.HubFullCommand{Command: circolog.CommandClear}
+			}
+			if sig == syscall.SIGUSR1 {
+				log.Println("Pause/resume")
+				hub.Commands <- circolog.HubFullCommand{Command: circolog.CommandPauseToggle}
 			}
 			if sig == syscall.SIGTERM || sig == syscall.SIGINT {
 				log.Println("Quitting because of signal", sig)

hub.go

@@ -24,10 +24,25 @@ type ClientOptions struct {
 // The channel "register" and "unregister" can be seen as "command"
 // keep in mind that "registering" is what you do also to get messages in a one-time fashion. In fact, Client
 // has "options", such as Nofollow, to explain the Hub what should be given
+
+// An HubCommand is an "enum" of different commands
+type HubCommand int
+
+const (
+	CommandClear       = iota
+	CommandPauseToggle = iota
+)
+
+// An HubFullCommand is a Command, complete with arguments
+type HubFullCommand struct {
+	Command HubCommand
+}
+
 type Hub struct {
 	Register    chan Client
 	Unregister  chan Client
 	LogMessages chan format.LogParts
+	Commands    chan HubFullCommand
 
 	clients map[Client]bool
 	circbuf *ring.Ring
@@ -39,6 +54,7 @@ func NewHub(ringBufSize int) Hub {
 		Register:    make(chan Client),
 		Unregister:  make(chan Client),
 		LogMessages: make(chan format.LogParts),
+		Commands:    make(chan HubFullCommand),
 		circbuf:     ring.New(ringBufSize),
 	}
 }
@@ -77,6 +93,7 @@ func (h *Hub) register(cl Client) {
 
 // Run is hub main loop; keeps everything going
 func (h *Hub) Run() {
+	active := true
 	for {
 		select {
 		case cl := <-h.Register:
@@ -88,22 +105,31 @@ func (h *Hub) Run() {
 				delete(h.clients, cl)
 			}
 		case msg := <-h.LogMessages:
-			h.circbuf.Value = msg
-			h.circbuf = h.circbuf.Next()
-			for client := range h.clients {
-				select { // send without blocking
-				case client.Messages <- msg:
-					break
-				default:
-					break
+			if active == true {
+				h.circbuf.Value = msg
+				h.circbuf = h.circbuf.Next()
+				for client := range h.clients {
+					select { // send without blocking
+					case client.Messages <- msg:
+						break
+					default:
+						break
+					}
 				}
 			}
+		case cmd := <-h.Commands:
+			if cmd.Command == CommandClear {
+				h.clear()
+			}
+			if cmd.Command == CommandPauseToggle {
+				active = !active
+			}
 		}
 	}
 }
 
 // Clear removes every all elements from the buffer
-func (h *Hub) Clear() {
+func (h *Hub) clear() {
 	buf := h.circbuf
 	for i := 0; i < buf.Len(); i++ {
 		buf.Value = nil