feat: add tls

cmd/server/main.go

@@ -2,16 +2,41 @@
 package main
 
 import (
+	"crypto/tls"
+	"crypto/x509"
+	"io/ioutil"
 	"net"
 
+	log "github.com/sirupsen/logrus"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
 
 	pb "github.com/esinio/geco/gen/proto/echo/v1"
 	srv "github.com/esinio/geco/service/echo/v1"
 )
 
 func main() {
-	s := grpc.NewServer()
+	cert, err := tls.LoadX509KeyPair("./cert/server.pem", "./cert/server.key")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	certPool := x509.NewCertPool()
+	ca, err := ioutil.ReadFile("./cert/ca.pem")
+	if err != nil {
+		log.Fatal(err)
+	}
+	if ok := certPool.AppendCertsFromPEM(ca); !ok {
+		log.Fatal("failed to append certs")
+	}
+
+	creds := credentials.NewTLS(&tls.Config{
+		Certificates: []tls.Certificate{cert},
+		ClientAuth:   tls.RequireAndVerifyClientCert, // NOTE: this is optional!
+		ClientCAs:    certPool,
+	})
+
+	s := grpc.NewServer(grpc.Creds(creds))
 	pb.RegisterEchoServiceServer(s, srv.NewService())
 	lis, err := net.Listen("tcp", ":9090")
 	if err != nil {