feat: initial implement of the gRPC middleware - logrus, prometheus

.gitignore

@@ -1,2 +1,3 @@
 .idea
 .DS_Store
+.vscode

server/cmd/server/main.go

@@ -3,31 +3,92 @@ package main
 import (
 	"fmt"
 	"net"
+	"net/http"
 
 	"github.com/codingpot/pr12er/server/pkg/env"
 	"github.com/codingpot/pr12er/server/pkg/pr12er"
 	"github.com/codingpot/pr12er/server/pkg/serv"
+	grpc_logrus "github.com/grpc-ecosystem/go-grpc-middleware/logging/logrus"
+	grpc_ctxtags "github.com/grpc-ecosystem/go-grpc-middleware/tags"
+	grpc_prometheus "github.com/grpc-ecosystem/go-grpc-prometheus"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	log "github.com/sirupsen/logrus"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/health"
 	"google.golang.org/grpc/health/grpc_health_v1"
 	"google.golang.org/grpc/reflection"
 )
 
+var (
+	logrusLogger *log.Logger
+	customFunc   grpc_logrus.CodeToLevel
+	logrusOpts   []grpc_logrus.Option
+	logrusEntry  *log.Entry
+)
+
+var (
+	reg         = prometheus.NewRegistry()
+	grpcMetrics = grpc_prometheus.NewServerMetrics()
+	promServer  *http.Server
+)
+
+func initPrometheus() {
+	reg.MustRegister(grpcMetrics)
+	promServer = &http.Server{
+		Handler: promhttp.HandlerFor(reg, promhttp.HandlerOpts{}),
+		Addr:    fmt.Sprintf("0.0.0.0:%s", env.PrometheusPort),
+	}
+}
+
+func initGrpcLogrus() {
+	logrusLogger = log.New()
+	customFunc = func(code codes.Code) log.Level {
+		if code == codes.OK {
+			return log.InfoLevel
+		}
+		return log.ErrorLevel
+	}
+
+	// Logrus entry is used, allowing pre-definition of certain fields by the user.
+	logrusEntry = log.NewEntry(logrusLogger)
+	// Shared options for the logger, with a custom gRPC code to log level function.
+	logrusOpts = []grpc_logrus.Option{
+		grpc_logrus.WithLevels(customFunc),
+	}
+	// Make sure that log statements internal to gRPC library are logged using the logrus Logger as well.
+	grpc_logrus.ReplaceGrpcLogger(logrusEntry)
+}
+
 func main() {
 	log.WithFields(log.Fields{
 		"Nversion":    env.Nversion,
 		"ServicePort": env.ServicePort,
 	}).Printf("gRPC server is listening at 0.0.0.0:%s", env.ServicePort)
 
+	initGrpcLogrus()
+	initPrometheus()
+
 	lis, err := net.Listen("tcp", fmt.Sprintf(":%s", env.ServicePort))
 	if err != nil {
 		log.WithError(err).Fatalf("failed to listen")
 	}
 
 	s := serv.Server{}
 
-	grpcServer := grpc.NewServer()
+	grpcServer := grpc.NewServer(
+		grpc.ChainUnaryInterceptor(
+			grpc_ctxtags.UnaryServerInterceptor(grpc_ctxtags.WithFieldExtractor(grpc_ctxtags.CodeGenRequestFieldExtractor)),
+			grpc_logrus.UnaryServerInterceptor(logrusEntry, logrusOpts...),
+			grpc_prometheus.UnaryServerInterceptor,
+		),
+		grpc.ChainStreamInterceptor(
+			grpc_ctxtags.StreamServerInterceptor(grpc_ctxtags.WithFieldExtractor(grpc_ctxtags.CodeGenRequestFieldExtractor)),
+			grpc_logrus.StreamServerInterceptor(logrusEntry, logrusOpts...),
+			grpc_prometheus.StreamServerInterceptor,
+		),
+	)
 
 	pr12er.RegisterPr12ErServiceServer(grpcServer, &s)
 
@@ -37,6 +98,20 @@ func main() {
 
 	reflection.Register(grpcServer)
 
+	// prometheus
+	grpc_prometheus.Register(grpcServer)
+	grpc_prometheus.EnableHandlingTimeHistogram()
+	grpcMetrics.InitializeMetrics(grpcServer)
+	// Register Prometheus metrics handler.
+	http.Handle("/metrics", promhttp.Handler())
+
+	// Start your http server for prometheus.
+	go func() {
+		if err := promServer.ListenAndServe(); err != nil {
+			log.Fatal("Unable to start a prometheus server.")
+		}
+	}()
+
 	if err := grpcServer.Serve(lis); err != nil {
 		log.WithError(err).Fatalf("failed to serve")
 	}

server/go.mod

@@ -3,13 +3,17 @@ module github.com/codingpot/pr12er/server
 go 1.16
 
 require (
-	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/grpc-ecosystem/go-grpc-middleware v1.3.0
+	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
+	github.com/prometheus/client_golang v1.10.0
+	github.com/prometheus/common v0.25.0 // indirect
 	github.com/sirupsen/logrus v1.8.1
 	github.com/stretchr/testify v1.5.1
-	golang.org/x/net v0.0.0-20210521195947-fe42d452be8f
-	golang.org/x/sys v0.0.0-20210510120138-977fb7262007 // indirect
-	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
+	golang.org/x/net v0.0.0-20210525063256-abc453219eb5
+	golang.org/x/sys v0.0.0-20210601080250-7ecdf8ef093b // indirect
+	google.golang.org/genproto v0.0.0-20210601170153-0befbe3492e2 // indirect
 	google.golang.org/grpc v1.38.0
 	google.golang.org/grpc/cmd/protoc-gen-go-grpc v1.1.0
 	google.golang.org/protobuf v1.26.0
+	gopkg.in/yaml.v2 v2.4.0 // indirect
 )