Self contained signal cmd build (#82)

* Moved Signal CMD to Signal directory

* Removed config dir and fixed a parameter typo

* removed attempt to create ssl directory

* Update Signal build configuration

* move Signal documentation to its directory

* removed unused variables

* test build management and signal

* User run as subcommand to execute the signal daemon

signal/cmd/run.go

@@ -0,0 +1,84 @@
+package cmd
+
+import (
+	"flag"
+	"fmt"
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+	"github.com/wiretrustee/wiretrustee/encryption"
+	"github.com/wiretrustee/wiretrustee/signal/proto"
+	"github.com/wiretrustee/wiretrustee/signal/server"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/keepalive"
+	"net"
+	"os"
+	"time"
+)
+
+var (
+	signalPort              int
+	signalLetsencryptDomain string
+	signalSSLDir            string
+
+	signalKaep = grpc.KeepaliveEnforcementPolicy(keepalive.EnforcementPolicy{
+		MinTime:             5 * time.Second,
+		PermitWithoutStream: true,
+	})
+
+	signalKasp = grpc.KeepaliveParams(keepalive.ServerParameters{
+		MaxConnectionIdle:     15 * time.Second,
+		MaxConnectionAgeGrace: 5 * time.Second,
+		Time:                  5 * time.Second,
+		Timeout:               2 * time.Second,
+	})
+
+	runCmd = &cobra.Command{
+		Use:   "run",
+		Short: "start Wiretrustee Signal Server daemon",
+		Run: func(cmd *cobra.Command, args []string) {
+			flag.Parse()
+
+			var opts []grpc.ServerOption
+			if signalLetsencryptDomain != "" {
+				if _, err := os.Stat(signalSSLDir); os.IsNotExist(err) {
+					err = os.MkdirAll(signalSSLDir, os.ModeDir)
+					if err != nil {
+						log.Fatalf("failed creating datadir: %s: %v", signalSSLDir, err)
+					}
+				}
+				certManager := encryption.CreateCertManager(signalSSLDir, signalLetsencryptDomain)
+				transportCredentials := credentials.NewTLS(certManager.TLSConfig())
+				opts = append(opts, grpc.Creds(transportCredentials))
+			}
+
+			opts = append(opts, signalKaep, signalKasp)
+			grpcServer := grpc.NewServer(opts...)
+
+			lis, err := net.Listen("tcp", fmt.Sprintf(":%d", signalPort))
+			if err != nil {
+				log.Fatalf("failed to listen: %v", err)
+			}
+
+			if err != nil {
+				log.Fatalf("failed to listen: %v", err)
+			}
+
+			proto.RegisterSignalExchangeServer(grpcServer, server.NewServer())
+			log.Printf("started server: localhost:%v", signalPort)
+			if err := grpcServer.Serve(lis); err != nil {
+				log.Fatalf("failed to serve: %v", err)
+			}
+
+			SetupCloseHandler()
+			<-stopCh
+			log.Println("Receive signal to stop running the Signal server")
+		},
+	}
+)
+
+func init() {
+	runCmd.PersistentFlags().IntVar(&signalPort, "port", 10000, "Server port to listen on (e.g. 10000)")
+	runCmd.Flags().StringVar(&signalSSLDir, "ssl-dir", "/var/lib/wiretrustee/", "server ssl directory location. *Required only for Let's Encrypt certificates.")
+	runCmd.Flags().StringVar(&signalLetsencryptDomain, "letsencrypt-domain", "", "a domain to issue Let's Encrypt certificate for. Enables TLS using Let's Encrypt. Will fetch and renew certificate, and run the server with TLS")
+}