Add a prometheus registry to the Server struct

This way the Server can be shut down leaving no state behind. We need this in
tests, when Servers are created and shut down repeatedly.

api/metricshttp/metricshttp.go

@@ -3,11 +3,12 @@ package metricshttp
 import (
 	"net/http"
 
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
-func NewMetricsHttp() *http.ServeMux {
+func NewMetricsHTTP(r *prometheus.Registry) *http.ServeMux {
 	mux := http.NewServeMux()
-	mux.Handle("/metrics", promhttp.Handler())
+	mux.Handle("/metrics", promhttp.HandlerFor(r, promhttp.HandlerOpts{}))
 	return mux
 }

server/server.go

@@ -44,23 +44,25 @@ import (
 	"github.com/bbva/qed/sign"
 	"github.com/bbva/qed/storage/badger"
 	"github.com/bbva/qed/util"
+	"github.com/prometheus/client_golang/prometheus"
 )
 
 // Server encapsulates the data and login to start/stop a QED server
 type Server struct {
 	conf      *Config
 	bootstrap bool // Set bootstrap to true when bringing up the first node as a master
 
-	httpServer      *http.Server
-	mgmtServer      *http.Server
-	raftBalloon     *raftwal.RaftBalloon
-	tamperingServer *http.Server
-	profilingServer *http.Server
-	metricsServer   *http.Server
-	signer          sign.Signer
-	sender          *sender.Sender
-	agent           *gossip.Agent
-	agentsQueue     chan *protocol.Snapshot
+	httpServer         *http.Server
+	mgmtServer         *http.Server
+	raftBalloon        *raftwal.RaftBalloon
+	tamperingServer    *http.Server
+	profilingServer    *http.Server
+	metricsServer      *http.Server
+	prometheusRegistry *prometheus.Registry
+	signer             sign.Signer
+	sender             *sender.Sender
+	agent              *gossip.Agent
+	agentsQueue        chan *protocol.Snapshot
 }
 
 func serverInfo(conf *Config) http.HandlerFunc {
@@ -167,7 +169,8 @@ func NewServer(conf *Config) (*Server, error) {
 		server.profilingServer = newHTTPServer("localhost:6060", nil)
 	}
 	if conf.EnableMetrics {
-		metricsMux := metricshttp.NewMetricsHttp()
+		server.prometheusRegistry = prometheus.NewRegistry()
+		metricsMux := metricshttp.NewMetricsHTTP(server.prometheusRegistry)
 		server.metricsServer = newHTTPServer("localhost:9990", metricsMux)
 	}