simpler amqp sink approach (#351)

controller/metrics/amqpSink.go

@@ -35,34 +35,35 @@ type amqpSink struct {
 	conn      *amqp.Connection
 	ch        *amqp.Channel
 	queue     amqp.Queue
-	join  chan struct{}
+	connected bool
 }
 
 func newAmqpSink(cfg *AmqpSinkConfig) (*amqpSink, error) {
-	return &amqpSink{
+	as := &amqpSink{
 		cfg: cfg,
-		join: make(chan struct{}),
-	}, nil
-}
-
-func (s *amqpSink) Start() (join chan struct{}, err error) {
-	logrus.Info("started")
-	return s.join, nil
+	}
+	return as, nil
 }
 
 func (s *amqpSink) Handle(event ZitiEventJson) error {
+	if !s.connected {
+		if err := s.connect(); err != nil {
+			return err
+		}
+		logrus.Infof("connected to '%v'", s.cfg.Url)
+		s.connected = true
+	}
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 	logrus.Infof("pushing '%v'", event)
-	return s.ch.PublishWithContext(ctx, "", s.queue.Name, false, false, amqp.Publishing{
+	err := s.ch.PublishWithContext(ctx, "", s.queue.Name, false, false, amqp.Publishing{
 		ContentType: "application/json",
 		Body:        []byte(event),
 	})
-}
-
-func (s *amqpSink) Stop() {
-	close(s.join)
-	logrus.Info("stopped")
+	if err != nil {
+		s.connected = false
+	}
+	return err
 }
 
 func (s *amqpSink) connect() (err error) {
@@ -70,18 +71,13 @@ func (s *amqpSink) connect() (err error) {
 	if err != nil {
 		return errors.Wrap(err, "error dialing amqp broker")
 	}
-
 	s.ch, err = s.conn.Channel()
 	if err != nil {
 		return errors.Wrap(err, "error getting amqp channel")
 	}
-
 	s.queue, err = s.ch.QueueDeclare(s.cfg.QueueName, true, false, false, false, nil)
 	if err != nil {
 		return errors.Wrap(err, "error declaring queue")
 	}
-
-	logrus.Infof("connected to amqp broker at '%v'", s.cfg.Url)
-
 	return nil
 }

controller/metrics/bridge.go

@@ -14,7 +14,6 @@ type Bridge struct {
 	src     ZitiEventJsonSource
 	srcJoin chan struct{}
 	snk     ZitiEventJsonSink
-	snkJoin chan struct{}
 	events  chan ZitiEventMsg
 	close   chan struct{}
 	join    chan struct{}
@@ -40,9 +39,6 @@ func NewBridge(cfg *BridgeConfig) (*Bridge, error) {
 }
 
 func (b *Bridge) Start() (join chan struct{}, err error) {
-	if b.snkJoin, err = b.snk.Start(); err != nil {
-		return nil, err
-	}
 	if b.srcJoin, err = b.src.Start(b.events); err != nil {
 		return nil, err
 	}
@@ -76,9 +72,7 @@ func (b *Bridge) Start() (join chan struct{}, err error) {
 
 func (b *Bridge) Stop() {
 	b.src.Stop()
-	b.snk.Stop()
 	close(b.close)
 	<-b.srcJoin
-	<-b.snkJoin
 	<-b.join
 }

controller/metrics/model.go

@@ -79,7 +79,5 @@ type ZitiEventJsonSource interface {
 }
 
 type ZitiEventJsonSink interface {
-	Start() (join chan struct{}, err error)
 	Handle(event ZitiEventJson) error
-	Stop()
 }