Separate server metrics from default definitions

metrics/definitions.go

@@ -21,12 +21,6 @@ import (
 )
 
 var (
-	QedInstancesCount = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Name: "qed_instances_count",
-			Help: "Number of QED servers currently running",
-		},
-	)
 
 	// API
 
@@ -127,7 +121,6 @@ var (
 	// PROMETHEUS
 
 	DefaultMetrics = []prometheus.Collector{
-		QedInstancesCount,
 		QedAPIHealthcheckRequestsTotal,
 
 		QedBalloonAddDurationSeconds,
@@ -141,4 +134,3 @@ var (
 		QedBalloonIncrementalTotal,
 	}
 )
-

metrics/metrics.go

@@ -48,6 +48,10 @@ type Registry interface {
 	MustRegister(...prometheus.Collector)
 }
 
+type Registerer interface {
+	RegisterMetrics(Registry)
+}
+
 // A metrics server holds the http API and the prometheus registry
 // which provides access to the registered metrics.
 type Server struct {

server/metrics.go

@@ -0,0 +1,47 @@
+/*
+   Copyright 2018-2019 Banco Bilbao Vizcaya Argentaria, S.A.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package server
+
+import "github.com/prometheus/client_golang/prometheus"
+
+// namespace is the leading part of all published metrics.
+const namespace = "qed"
+
+// subsystem associated with metrics for server
+const subsystem = "server"
+
+type serverMetrics struct {
+	Instances prometheus.Gauge
+}
+
+func newServerMetrics() *serverMetrics {
+	return &serverMetrics{
+		Instances: prometheus.NewGauge(
+			prometheus.GaugeOpts{
+				Name: "instances",
+				Help: "Number of QED servers currently running",
+			},
+		),
+	}
+}
+
+// collectors satisfies the prom.PrometheusCollector interface.
+func (m *serverMetrics) collectors() []prometheus.Collector {
+	return []prometheus.Collector{
+		m.Instances,
+	}
+}

server/server.go

@@ -53,6 +53,7 @@ type Server struct {
 	httpServer         *http.Server
 	mgmtServer         *http.Server
 	raftBalloon        *raftwal.RaftBalloon
+	metrics            *serverMetrics
 	metricsServer      *metrics.Server
 	prometheusRegistry *prometheus.Registry
 	signer             sign.Signer
@@ -119,8 +120,9 @@ func NewServer(conf *Config) (*Server, error) {
 	}
 
 	// create metrics server and register default qed metrics
+	server.metrics = newServerMetrics()
 	server.metricsServer = metrics.NewServer(conf.MetricsAddr)
-	server.metricsServer.MustRegister(metrics.DefaultMetrics...)
+	server.RegisterMetrics(server.metricsServer)
 	store.RegisterMetrics(server.metricsServer)
 	// server.metricsServer.Register(raft.PrometheusCollectors())
 	// server.metricsServer.Register(balloon.PrometheusCollectors())
@@ -195,7 +197,7 @@ func join(joinAddr, raftAddr, nodeID string, metadata map[string]string) error {
 
 // Start will start the server in a non-blockable fashion.
 func (s *Server) Start() error {
-	metrics.QedInstancesCount.Inc()
+	s.metrics.Instances.Inc()
 	log.Infof("Starting QED server %s\n", s.conf.NodeID)
 
 	metadata := map[string]string{}
@@ -264,7 +266,7 @@ func (s *Server) Start() error {
 
 // Stop will close all the channels from the mux servers.
 func (s *Server) Stop() error {
-	metrics.QedInstancesCount.Dec()
+	s.metrics.Instances.Dec()
 	log.Infof("\nShutting down QED server %s", s.conf.NodeID)
 
 	log.Debugf("Metrics enabled: stopping server...")
@@ -303,6 +305,13 @@ func (s *Server) Stop() error {
 	return nil
 }
 
+func (s *Server) RegisterMetrics(registry metrics.Registry) {
+	if registry != nil {
+		registry.MustRegister(s.metrics.collectors()...)
+		registry.MustRegister(metrics.DefaultMetrics...) // TODO: remove this!!!
+	}
+}
+
 func newTLSServer(addr string, mux *http.ServeMux) *http.Server {
 
 	cfg := &tls.Config{

storage/store.go

@@ -102,7 +102,7 @@ type ManagedStore interface {
 	Backup(w io.Writer, until uint64) error
 	Snapshot() (uint64, error)
 	Load(r io.Reader) error
-	RegisterMetrics(metrics.Registry)
+	metrics.Registerer
 }
 
 type Mutation struct {