Run gPRC health server if grpc-port flag is set

Makefile

@@ -10,7 +10,7 @@ GIT_COMMIT:=$(shell git describe --dirty --always)
 VERSION:=$(shell grep 'VERSION' pkg/version/version.go | awk '{ print $$4 }' | tr -d '"')
 
 run:
-	GO111MODULE=on go run -ldflags "-s -w -X github.com/stefanprodan/podinfo/pkg/version.REVISION=$(GIT_COMMIT)" cmd/podinfo/* --level=debug
+	GO111MODULE=on go run -ldflags "-s -w -X github.com/stefanprodan/podinfo/pkg/version.REVISION=$(GIT_COMMIT)" cmd/podinfo/* --level=debug --grpc-port=9999
 
 test:
 	GO111MODULE=on go test -v -race ./...

cmd/podinfo/main.go

@@ -2,26 +2,31 @@ package main
 
 import (
 	"fmt"
-	"github.com/spf13/pflag"
-	"github.com/spf13/viper"
-	"github.com/stefanprodan/podinfo/pkg/api"
-	"github.com/stefanprodan/podinfo/pkg/signals"
-	"github.com/stefanprodan/podinfo/pkg/version"
-	"go.uber.org/zap"
-	"go.uber.org/zap/zapcore"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
+
+	"github.com/spf13/pflag"
+	"github.com/spf13/viper"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+
+	"github.com/stefanprodan/podinfo/pkg/api"
+	"github.com/stefanprodan/podinfo/pkg/grpc"
+	"github.com/stefanprodan/podinfo/pkg/signals"
+	"github.com/stefanprodan/podinfo/pkg/version"
 )
 
 func main() {
 	// flags definition
 	fs := pflag.NewFlagSet("default", pflag.ContinueOnError)
-	fs.Int("port", 9898, "port")
+	fs.Int("port", 9898, "HTTP port")
 	fs.Int("port-metrics", 0, "metrics port")
+	fs.Int("grpc-port", 0, "gRPC port")
+	fs.String("grpc-service-name", "podinfo", "gPRC service name")
 	fs.String("level", "info", "log level debug, info, warn, error, flat or panic")
 	fs.String("backend-url", "", "backend service URL")
 	fs.Duration("http-client-timeout", 2*time.Minute, "client timeout duration")
@@ -90,6 +95,18 @@ func main() {
 		viper.Set("port", strconv.Itoa(port))
 	}
 
+	// load gRPC server config
+	var grpcCfg grpc.Config
+	if err := viper.Unmarshal(&grpcCfg); err != nil {
+		logger.Panic("config unmarshal failed", zap.Error(err))
+	}
+
+	// start gRPC server
+	if grpcCfg.Port > 0 {
+		grpcSrv, _ := grpc.NewServer(&grpcCfg, logger)
+		go grpcSrv.ListenAndServe()
+	}
+
 	// load HTTP server config
 	var srvCfg api.Config
 	if err := viper.Unmarshal(&srvCfg); err != nil {

pkg/grpc/server.go

@@ -16,7 +16,7 @@ type Server struct {
 }
 
 type Config struct {
-	Port        string `mapstructure:"grpc-port"`
+	Port        int    `mapstructure:"grpc-port"`
 	ServiceName string `mapstructure:"grpc-service-name"`
 }
 
@@ -30,9 +30,9 @@ func NewServer(config *Config, logger *zap.Logger) (*Server, error) {
 }
 
 func (s *Server) ListenAndServe() {
-	listener, err := net.Listen("tcp", fmt.Sprintf(":%s", s.config.Port))
+	listener, err := net.Listen("tcp", fmt.Sprintf(":%v", s.config.Port))
 	if err != nil {
-		s.logger.Fatal("failed to listen", zap.String("port", s.config.Port))
+		s.logger.Fatal("failed to listen", zap.Int("port", s.config.Port))
 	}
 
 	srv := grpc.NewServer()