expose grpc metrics in prometheus

Author: matthieugouel

README.md

@@ -34,6 +34,8 @@ The Octopus exposes a number of metrics via an HTTP endpoint ready to be scraped
  * `octopus_connector_load_time` - Time it took to fetch data (milliseconds) (broken out by label `connector`)
  * `octopus_connector_update_error_count` - The number of time the refresh of connector data has failed (broken out by label `connector`)
 
+ Other than those, Octopus is exposing gRPC-related metrics that comes from [go-grpc-middleware](https://github.com/grpc-ecosystem/go-grpc-middleware/tree/main/providers/prometheus).
+
 # Querying data
 
 The Octopus exposes a gRPC API to query the enriched topology data.

go.mod

@@ -5,10 +5,11 @@ go 1.19
 require (
 	github.com/bio-routing/bio-rd v0.1.9
 	github.com/go-pg/pg v8.0.7+incompatible
-	github.com/prometheus/client_golang v1.11.1
+	github.com/grpc-ecosystem/go-grpc-middleware/providers/prometheus v1.0.1
+	github.com/prometheus/client_golang v1.14.0
 	github.com/sirupsen/logrus v1.9.0
-	github.com/stretchr/testify v1.8.2
-	google.golang.org/grpc v1.56.3
+	github.com/stretchr/testify v1.8.4
+	google.golang.org/grpc v1.63.2
 	google.golang.org/protobuf v1.33.0
 )
 
@@ -17,20 +18,21 @@ require (
 	github.com/bio-routing/tflow2 v0.0.0-20181230153523-2e308a4a3c3a // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/golang/protobuf v1.5.3 // indirect
+	github.com/golang/protobuf v1.5.4 // indirect
+	github.com/grpc-ecosystem/go-grpc-middleware/v2 v2.1.0 // indirect
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
 	github.com/onsi/ginkgo v1.16.5 // indirect
 	github.com/onsi/gomega v1.27.6 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_model v0.3.0 // indirect
-	github.com/prometheus/common v0.26.0 // indirect
+	github.com/prometheus/common v0.37.0 // indirect
 	github.com/prometheus/procfs v0.9.0 // indirect
-	golang.org/x/crypto v0.21.0 // indirect
-	golang.org/x/net v0.23.0 // indirect
-	golang.org/x/sys v0.18.0 // indirect
+	golang.org/x/crypto v0.22.0 // indirect
+	golang.org/x/net v0.24.0 // indirect
+	golang.org/x/sys v0.19.0 // indirect
 	golang.org/x/text v0.14.0 // indirect
-	google.golang.org/genproto v0.0.0-20230410155749-daa745c078e1 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240415180920-8c6c420018be // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	mellium.im/sasl v0.3.1 // indirect
 )

go.sum

@@ -17,6 +17,8 @@ import (
 	"github.com/cloudflare/octopus/pkg/connector"
 	"github.com/cloudflare/octopus/pkg/model"
 	octopuspb "github.com/cloudflare/octopus/proto/octopus"
+	grpcprom "github.com/grpc-ecosystem/go-grpc-middleware/providers/prometheus"
+	"github.com/prometheus/client_golang/prometheus"
 
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/reflection"
@@ -131,9 +133,18 @@ func (o *Octopus) serveGrpc() {
 	log.Infof("Starting gRPC API server at %s", portStr)
 
 	os := newOctopusServer(o)
-	s := grpc.NewServer()
+
+	srvMetrics := grpcprom.NewServerMetrics()
+	s := grpc.NewServer(
+		grpc.UnaryInterceptor(srvMetrics.UnaryServerInterceptor()),
+		grpc.StreamInterceptor(srvMetrics.StreamServerInterceptor()),
+	)
 	s.RegisterService(&octopuspb.OctopusService_ServiceDesc, os)
 
+	// Register Prometheus metrics
+	srvMetrics.InitializeMetrics(s)
+	prometheus.MustRegister(srvMetrics)
+
 	// Allow client to retrieve proto definition
 	reflection.Register(s)