WIP: Clsuter support (cross node delivery, leader election)

metrics/metrics.go

@@ -75,6 +75,33 @@ var (
 	HTTPRequests = prometheus.NewCounterVec(prometheus.CounterOpts{
 		Name: "ntfy_http_requests_total",
 	}, []string{"http_code", "ntfy_code", "http_method"})
+	ClusterPeers = prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "ntfy_cluster_peers",
+	})
+	ClusterMessagesRelayed = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "ntfy_cluster_messages_relayed_total",
+	})
+	ClusterSendErrors = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "ntfy_cluster_send_errors_total",
+	})
+	ClusterQueueDropped = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "ntfy_cluster_queue_dropped_total",
+	})
+	ClusterBatchesSent = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "ntfy_cluster_batches_sent_total",
+	})
+	ClusterMessagesWasted = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "ntfy_cluster_messages_wasted_total",
+	})
+	ClusterRouteSkipped = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "ntfy_cluster_route_skipped_total",
+	})
+	ClusterStatePushes = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "ntfy_cluster_state_pushes_total",
+	})
+	ClusterLeader = prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "ntfy_cluster_leader",
+	})
 )
 
 // init registers all collectors with the default Prometheus registry. Registration is
@@ -103,5 +130,14 @@ func init() {
 		Subscribers,
 		Topics,
 		HTTPRequests,
+		ClusterPeers,
+		ClusterMessagesRelayed,
+		ClusterSendErrors,
+		ClusterQueueDropped,
+		ClusterBatchesSent,
+		ClusterMessagesWasted,
+		ClusterRouteSkipped,
+		ClusterStatePushes,
+		ClusterLeader,
 	)
 }

metrics/metrics_test.go

@@ -15,6 +15,15 @@ var expectedMetricNames = []string{
 	"ntfy_attachments_total_size",
 	"ntfy_calls_made_failure",
 	"ntfy_calls_made_success",
+	"ntfy_cluster_batches_sent_total",
+	"ntfy_cluster_leader",
+	"ntfy_cluster_messages_relayed_total",
+	"ntfy_cluster_messages_wasted_total",
+	"ntfy_cluster_peers",
+	"ntfy_cluster_queue_dropped_total",
+	"ntfy_cluster_route_skipped_total",
+	"ntfy_cluster_send_errors_total",
+	"ntfy_cluster_state_pushes_total",
 	"ntfy_emails_received_failure",
 	"ntfy_emails_received_success",
 	"ntfy_emails_sent_failure",