feat: Add Create RPC to dhclientd (#10)

Author: pojntfx

cmd/constants.go

@@ -1,7 +1,8 @@
 package cmd
 
 const (
-	DHCPDDHostPortDefault = "localhost:1240" // DHCPDDHostPortDefault is the default Host:port that of `dhcpdd`.
+	DHCPDDHostPortDefault    = "localhost:1240" // DHCPDDHostPortDefault is the default Host:port of `dhcpdd`.
+	DHClientDHostPortDefault = "localhost:1241" // DHClientDHostPortDefault is the default Host:port of `dhclient`.
 )
 
 const (

cmd/dhclientd/main.go

@@ -0,0 +1,134 @@
+package main
+
+import (
+	constants "github.com/pojntfx/godhcpd/cmd"
+	godhcpd "github.com/pojntfx/godhcpd/pkg/proto/generated"
+	"github.com/pojntfx/godhcpd/pkg/svc"
+	"github.com/pojntfx/godhcpd/pkg/workers"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"gitlab.com/bloom42/libs/rz-go"
+	"gitlab.com/bloom42/libs/rz-go/log"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/reflection"
+	"net"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"strings"
+	"syscall"
+)
+
+const (
+	keyPrefix         = "dhclientd."
+	configFileDefault = ""
+	configFileKey     = keyPrefix + "configFile"
+	listenHostPortKey = keyPrefix + "listenHostPort"
+)
+
+var rootCmd = &cobra.Command{
+	Use:   "dhclientd",
+	Short: "dhclientd is the ISC DHCP client management daemon",
+	Long: `dhclientd is the ISC DHCP client management daemon.
+
+Find more information at:
+https://pojntfx.github.io/godhcpd/`,
+	PersistentPreRun: func(cmd *cobra.Command, args []string) {
+		viper.SetEnvPrefix("dhclientd")
+		viper.SetEnvKeyReplacer(strings.NewReplacer("-", "_", ".", "_"))
+	},
+	RunE: func(cmd *cobra.Command, args []string) error {
+		if !(viper.GetString(configFileKey) == configFileDefault) {
+			viper.SetConfigFile(viper.GetString(configFileKey))
+
+			if err := viper.ReadInConfig(); err != nil {
+				return err
+			}
+		}
+		binaryDir := filepath.Join(os.TempDir(), "dhclient")
+
+		listener, err := net.Listen("tcp", viper.GetString(listenHostPortKey))
+		if err != nil {
+			return err
+		}
+
+		server := grpc.NewServer()
+		reflection.Register(server)
+
+		DHClientService := svc.DHClientManager{
+			BinaryDir:        binaryDir,
+			DHClientsManaged: make(map[string]*workers.DHClient),
+		}
+
+		godhcpd.RegisterDHClientManagerServer(server, &DHClientService)
+
+		interrupt := make(chan os.Signal, 2)
+		signal.Notify(interrupt, os.Interrupt, syscall.SIGTERM)
+		go func() {
+			<-interrupt
+
+			// Allow manually killing the process
+			go func() {
+				<-interrupt
+
+				os.Exit(1)
+			}()
+
+			log.Info("Gracefully stopping server (this might take a few seconds)")
+
+			msg := "Could not stop dhcp server"
+
+			for _, DHClient := range DHClientService.DHClientsManaged {
+				if err := DHClient.DisableAutoRestart(); err != nil { // Manually disable auto restart; disables crash recovery even if process is not running
+					log.Fatal(msg, rz.Err(err))
+				}
+
+				if DHClient.IsRunning() {
+					if err := DHClient.Stop(); err != nil { // Stop is sync, so no need to `.Wait()`
+						log.Fatal(msg, rz.Err(err))
+					}
+				}
+			}
+
+			if err := DHClientService.Cleanup(); err != nil {
+				log.Fatal(msg, rz.Err(err))
+			}
+
+			server.GracefulStop()
+		}()
+
+		if err := DHClientService.Extract(); err != nil {
+			return err
+		}
+
+		log.Info("Starting server")
+
+		if err := server.Serve(listener); err != nil {
+			return err
+		}
+
+		return nil
+	},
+}
+
+func init() {
+	var (
+		configFileFlag string
+		hostPortFlag   string
+	)
+
+	rootCmd.PersistentFlags().StringVarP(&configFileFlag, configFileKey, "f", configFileDefault, "Configuration file to use.")
+	rootCmd.PersistentFlags().StringVarP(&hostPortFlag, listenHostPortKey, "l", constants.DHClientDHostPortDefault, "TCP listen host:port.")
+
+	if err := viper.BindPFlags(rootCmd.PersistentFlags()); err != nil {
+		log.Fatal(constants.CouldNotBindFlagsErrorMessage, rz.Err(err))
+	}
+
+	viper.AutomaticEnv()
+}
+
+func main() {
+	if err := rootCmd.Execute(); err != nil {
+		log.Fatal(constants.CouldNotStartRootCommandErrorMessage, rz.Err(err))
+	}
+}

go.sum

@@ -24,6 +24,7 @@ github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfb
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.2 h1:6nsPYzhq5kReh6QImI3k5qWzO4PEbvbIW2cwSfR/6xs=
 github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/google/go-cmp v0.2.0 h1:+dTQ8DZQJz0Mb/HjFlkptS1FeQ4cWSnN941F8aEG4SQ=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
 github.com/gosuri/uitable v0.0.4 h1:IG2xLKRvErL3uhY6e1BylFzG+aJiwQviDDTfOKeKTpY=

pkg/proto/dhclient.proto

@@ -0,0 +1,26 @@
+syntax = "proto3";
+
+package godhcpd;
+
+// DHClientManager manages DHCP clients.
+service DHClientManager {
+  rpc Create(DHClient) returns (DHClientManagedId) {};
+  rpc List(DHClientManagerListArgs) returns (DHClientManagerListReply) {};
+  rpc Get(DHClientManagedId) returns (DHClientManaged) {};
+  rpc Delete(DHClientManagedId) returns (DHClientManagedId) {};
+}
+
+message DHClient { string Device = 1; }
+
+message DHClientManaged {
+  string Id = 1;
+  string Device = 2;
+}
+
+message DHClientManagerListArgs {}
+
+message DHClientManagedId { string Id = 1; }
+
+message DHClientManagerListReply {
+  repeated DHClientManaged DHClientsManaged = 1;
+}