Fixing Duplicate Metrics Registration when Unsetting preInit

internal/apiserver/server.go

@@ -44,8 +44,6 @@ import (
 	"github.com/hyperledger/firefly/internal/orchestrator"
 	"github.com/hyperledger/firefly/pkg/database"
 	"github.com/hyperledger/firefly/pkg/fftypes"
-	"github.com/prometheus/client_golang/prometheus"
-	muxprom "gitlab.com/hfuss/mux-prometheus/pkg/middleware"
 )
 
 var ffcodeExtractor = regexp.MustCompile(`^(FF\d+):`)
@@ -436,23 +434,12 @@ func (as *apiServer) swaggerHandler(routes []*oapispec.Route, url string) func(r
 	}
 }
 
-func (as *apiServer) configurePrometheusInstrumentation(namespace, subsystem string, r *mux.Router) {
-	if as.metricsEnabled {
-		instrumentation := muxprom.NewCustomInstrumentation(
-			true,
-			namespace,
-			subsystem,
-			prometheus.DefBuckets,
-			map[string]string{},
-			metrics.Registry(),
-		)
-		r.Use(instrumentation.Middleware)
-	}
-}
-
 func (as *apiServer) createMuxRouter(ctx context.Context, o orchestrator.Orchestrator) *mux.Router {
 	r := mux.NewRouter()
-	as.configurePrometheusInstrumentation("ff_apiserver", "rest", r)
+
+	if as.metricsEnabled {
+		r.Use(metrics.GetRestServerInstrumentation().Middleware)
+	}
 
 	for _, route := range routes {
 		if route.JSONHandler != nil {
@@ -479,7 +466,9 @@ func (as *apiServer) createMuxRouter(ctx context.Context, o orchestrator.Orchest
 
 func (as *apiServer) createAdminMuxRouter(o orchestrator.Orchestrator) *mux.Router {
 	r := mux.NewRouter()
-	as.configurePrometheusInstrumentation("ff_apiserver", "admin", r)
+	if as.metricsEnabled {
+		r.Use(metrics.GetAdminServerInstrumentation().Middleware)
+	}
 
 	for _, route := range adminRoutes {
 		if route.JSONHandler != nil {

internal/metrics/metrics.go

@@ -1,4 +1,4 @@
-// Copyright © 2021 Kaleido, Inc.
+// Copyright © 2022 Kaleido, Inc.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -19,9 +19,12 @@ package metrics
 import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/collectors"
+	muxprom "gitlab.com/hfuss/mux-prometheus/pkg/middleware"
 )
 
 var registry *prometheus.Registry
+var adminInstrumentation *muxprom.Instrumentation
+var restInstrumentation *muxprom.Instrumentation
 var BatchPinCounter prometheus.Counter
 
 // MetricsBatchPin is the prometheus metric for total number of batch pins submitted
@@ -38,6 +41,35 @@ func Registry() *prometheus.Registry {
 	return registry
 }
 
+// GetAdminServerInstrumentation returns the admin server's Prometheus middleware, ensuring its metrics are never
+// registered twice
+func GetAdminServerInstrumentation() *muxprom.Instrumentation {
+	if adminInstrumentation == nil {
+		adminInstrumentation = newInstrumentation("admin")
+	}
+	return adminInstrumentation
+}
+
+// GetRestServerInstrumentation returns the REST server's Prometheus middleware, ensuring its metrics are never
+// registered twice
+func GetRestServerInstrumentation() *muxprom.Instrumentation {
+	if restInstrumentation == nil {
+		restInstrumentation = newInstrumentation("rest")
+	}
+	return restInstrumentation
+}
+
+func newInstrumentation(subsystem string) *muxprom.Instrumentation {
+	return muxprom.NewCustomInstrumentation(
+		true,
+		"ff_apiserver",
+		subsystem,
+		prometheus.DefBuckets,
+		map[string]string{},
+		Registry(),
+	)
+}
+
 func initMetricsCollectors() {
 	BatchPinCounter = prometheus.NewCounter(prometheus.CounterOpts{
 		Name: MetricsBatchPin,
@@ -51,7 +83,9 @@ func registerMetricsCollectors() {
 	registry.MustRegister(BatchPinCounter)
 }
 
-// Clear will reset the Prometheus metrics registry, useful for testing
+// Clear will reset the Prometheus metrics registry and instrumentations, useful for testing
 func Clear() {
 	registry = nil
+	adminInstrumentation = nil
+	restInstrumentation = nil
 }

test/e2e/run.sh

@@ -67,7 +67,7 @@ if [ "$BUILD_FIREFLY" == "true" ]; then
 fi
 
 if [ "$DOWNLOAD_CLI" == "true" ]; then
-  go install github.com/hyperledger/firefly-cli/ff@v0.0.40
+  go install github.com/hyperledger/firefly-cli/ff@v0.0.41
   checkOk $?
 fi